AQMx Sectoral Guidance: Vehicle Inspection and Maintenance Programmes

In-use vehicles are a major source of greenhouse gases, short-lived climate pollutants, and criteria air pollutants (UNEP/CCAC, 2025). While vehicle emission standards address new vehicles, Inspection and Maintenance (I/M) programs are the primary tool for controlling emissions from the existing fleet. This role is critical because modern emission-control technologies are highly sensitive to poor maintenance, fuel quality, and tampering, which can erase the benefits of stringent standards (Giechaskiel, 2022). Without robust I/M, malfunctioning or disabled systems remain undetected, allowing high-emitting vehicles to lock in real-world emissions far above regulatory standards (Yuhan at all, 2022).

This challenge is especially acute in low- and middle-income countries, where fleets are often older and dominated by imported used vehicles (World Bank, 2022; European Automobile Manufacturers’ Association, 2023). These vehicles may already have degraded or missing emission-control systems upon arrival (UNEP, 2020). Weak enforcement and a lack of trained technicians can further encourage tampering. A relatively small share of these poorly maintained vehicles, or “super-emitters,” can account for a disproportionate fraction of on-road pollution (Smit, 2025). In this context, I/M is not merely an administrative check; it is a cornerstone of effective air-quality management. By identifying both high-emitting vehicles and critical mechanical defects, I/M programs also provide a significant co-benefit by improving road safety. 

The transport sector is a major contributor to global climate and air pollution. According to the Intergovernmental Panel on Climate Change (IPCC, 2022), transport accounts for roughly 15% of total greenhouse gas (GHG) emissions and about 23% of global energy-related CO₂ emissions. Road transport is the dominant source, producing about 77% of transport-related CO₂ emissions—representing around 11–18% of total global CO₂ emissions (IPCC, 2022; REN21, 2023; WRI, 2024).

Road transport is also a major emitter of short-lived climate pollutants (SLCPs), particularly black carbon, which contributes about 8% of global black-carbon emissions (CEDS). In addition, road vehicles emit nitrogen oxides (NOₓ), volatile organic compounds (VOCs), carbon monoxide (CO), and fine particulate matter (PM2.5), which are key drivers of urban air pollution and health impacts (EDGAR, 2025). A significant share of these impacts is driven by poorly maintained and high-emitting vehicles. Inspection and Maintenance programs therefore play a critical supporting role in translating vehicle standards and cleaner fuels into real-world emission reductions.

AQMx Guidance on Fuel Quality

AQMx Guidance on Vehicle Emission Standards

Health impacts

Transport emissions—particularly from road vehicles—are among the leading environmental risks to human health. Exposure to fine particulate matter (PM2.5), nitrogen oxides (NOₓ), ozone, volatile organic compounds (VOCs), and black carbon is linked to ischemic heart disease, stroke, chronic obstructive pulmonary disease (COPD), asthma, lung cancer, and respiratory infections. The World Health Organization (WHO, 2024) identifies ambient air pollution as a top global health threat, responsible for millions of premature deaths annually. On-road vehicle emissions accounted for approximately 385,000 premature deaths in 2015 in one global estimate (ICCT, 2019), and broader analysis indicates motorized road transport contributes around 1.5 million deaths yearly worldwide—including about 184,000 specifically from vehicle-emission-related air pollution, mainly due to cardiovascular and respiratory diseases linked to PM2.5 (World Bank, 2014). The sector accounts for the loss of more than 80 million healthy years of life (DALYs) annually. Modeling by Silva et al. (2016) suggests transport contributes 11–16% of global ambient-air-pollution mortality. Long-term exposure is associated with increased hospital admissions, impaired lung function in children, adverse birth outcomes, and emerging evidence links chronic exposure to diabetes, hypertension, and cognitive decline.

Agriculture and ecosystems impacts

Environmental consequences are equally severe. Ozone and particulate pollution reduce crop yields and impair vegetation growth, eroding food security and ecosystem services (Mills et al., 2018). Black carbon and other short-lived climate pollutants accelerate glacier melting and regional warming, amplifying climate impacts beyond CO₂. In cities, transport-related pollution contributes to visibility loss, urban heat islands, and environmental degradation, disproportionately affecting vulnerable populations living near major roads or freight corridors.

Economic impacts

The economic and social burden is immense. Welfare losses from ambient air pollution are estimated at trillions of U.S. dollars annually—valued at several percentage points of global GDP (World Bank, 2016). In developing economies, the cost of inaction manifests in reduced worker productivity, increased public-health expenditure, and disproportionate burdens on low-income and marginalized communities facing higher exposure with fewer mitigation options.

The cumulative health, environmental, social, and economic impacts make transport emissions one of the most consequential cross-sectoral challenges for sustainable development—and underscore the urgency of coordinated policy action worldwide. 

Inspection and Maintenance (I&M) programs are proven tools for reducing harmful vehicle emissions. International evidence confirms that I&M programs typically reduce exhaust pollution by around 10% or more, while also identifying a small share of poorly maintained vehicles that account for a disproportionate share of emissions (Smit et al., 2025; Ventura et al., 2020). Evidence from California shows that systematic inspections and repairs cut major pollutants such as carbon monoxide and hydrocarbons by around 25–35%, with measurable reductions in nitrogen oxides as well (Singer & Wenzel, 2003). These emission reductions generate substantial public-health benefits, including reduced incidence of respiratory and cardiovascular disease. Many I&M programs also contribute directly to road safety by identifying critical mechanical defects (WHO, 2021).

Beyond these direct gains, I&M systems strengthen transport regulation and governance. They reinforce anti-tampering policies, improve fuel efficiency, and enhance monitoring, reporting, and verification (MRV) systems by generating high-quality data. This data can be used to track emissions reductions, support nationally determined contribution reporting, and prioritize enforcement, supporting a more equitable transition toward cleaner and safer mobility. 

This scenario applies to countries with established vehicle registration systems, inspection records, or enforcement databases. The focus is on using official national data to calibrate policy, strengthen enforcement, and measure real-world impacts.

1. Inspection and Maintenance System Assessment

The objective is to assess the coverage, effectiveness, and integrity of existing I/M systems using verifiable local data. This includes pass/fail rates, test frequency, vehicle categories covered, test methods used, and penalties for non-compliance.

2. Vehicle Fleet Profile and Fuel Quality Assessment

The objective is to determine the age, technology level, fuel quality, and emissions-control characteristics of the in-use fleet using centralized vehicle registration databases and inspection results.

3. Air Pollution Levels and Health Impact Assessment

The objective is to link in-use vehicle conditions to observed air-quality and health outcomes using local evidence from national air-quality monitoring networks and health statistics, consistent with World Health Organization Air Quality Guidelines (WHO, 2021).

4. Road Transport Contribution Assessment

The objective is to attribute air pollution and exposure to the road transport sector using national or local emissions inventories, supplemented with source-apportionment studies or roadside measurement campaigns. In addition to traditional roadside checks, remote emissions sensing can provide a high-volume, low-disruption way to identify high emitters and to estimate real-world emission factors for the in-use fleet (ICCT, 2018). 

Where formal inspection records or fleet databases are limited, governments can rely on credible proxy indicators to design initial I/M policies and build systems incrementally.

1. Inspection and Enforcement Framework Assessment

The objective is to assess the likely effectiveness of existing I/M systems using indirect evidence, such as legal frameworks, institutional arrangements, and regional harmonization mechanisms.

As with fuel quality, harmonized regional approaches are particularly important in preventing regulatory leakage, cross-border evasion, and the circulation of unsafe or high-emitting vehicles across jurisdictions. Countries without strong I/M systems are often exposed to inflows of deteriorated or tampered vehicles from neighboring markets, undermining national air-quality and road-safety objectives.

What to evaluate:

• Existence of a legal requirement for periodic vehicle inspection
• Vehicle categories covered (light-duty, heavy-duty, motorcycles, commercial fleets)
• Inspection frequency by vehicle type and age
• Scope of inspection (roadworthiness only vs. roadworthiness plus emissions)
• Inclusion of anti-tampering checks
• Linkage between inspection results and vehicle registration, licensing, or insurance
• Penalties for non-compliance or failed inspections
• Presence of roadside inspections or enforcement checks
• Institutional responsibilities (transport authority, police, environment agency)
• Alignment with international or regional vehicle standards

Key regulatory references, frameworks and platforms:

• European Union Roadworthiness Package (Directive 2014/45/EU and Directive 2014/47/EU): Establishes binding minimum requirements for periodic technical inspection and roadside inspections, including emissions-related checks, inspector competence, and quality assurance. Widely used as a global benchmark for integrated safety-and-emissions Inspection and Maintenance systems.
• UNECE World Forum for Harmonization of Vehicle Regulations (WP.29): Provides the international framework for vehicle emission standards, durability requirements, and anti-tampering principles that underpin effective in-use compliance systems.
• United States Clean Air Act – Vehicle Inspection and Maintenance Programs: Requires emissions inspection programs in designated air-quality nonattainment areas and provides detailed guidance on program design, performance evaluation, and enforcement credibility.
• WHO Global Plan for the Decade of Action for Road Safety (2021–2030): Recognizes periodic vehicle inspection as a core road-safety intervention, providing a public-health rationale for I/M systems even where emissions data is limited. Recognizes periodic vehicle inspection as a core road-safety intervention, providing a public-health rationale for I/M systems even where emissions data is limited.
• CITA – International Motor Vehicle Inspection Committee: Global network of inspection authorities and operators providing guidance, technical papers, and benchmarking on vehicle inspection systems, inspector training, and quality assurance.

Regional approaches to inspection and maintenance (I/M) systems

• ECOWAS – Periodic Vehicle Inspection Harmonization (West Africa): The Economic Community of West African States (ECOWAS) does not yet have a fully binding regional inspection and maintenance regulation, but it has established regional principles for vehicle roadworthiness and technical inspection through its transport harmonization instruments. ECOWAS supplementary acts and road-transport regulations promote mandatory periodic technical inspection, particularly for commercial and cross-border vehicles, as a means to improve road safety and control unsafe, high-emitting vehicles. While implementation remains at the national level, regional coordination helps reduce cross-border circulation of poorly maintained vehicles and supports consistency with ECOWAS fuel-quality harmonization efforts.  
• East African Community (EAC) – Coordinated Vehicle Inspection Frameworks (East Africa): The East African Community has promoted convergence in vehicle inspection and roadworthiness practices through regional cooperation on road safety and environmental protection, consistent with African Union and UNECA road safety frameworks that emphasize harmonization and mandatory vehicle inspection, while leaving implementation to national authorities. EAC partner states broadly require periodic technical inspection for commercial vehicles and public transport fleets, and regional dialogue has emphasized harmonizing inspection scope, enforcement practices, and cross-border recognition of inspection certificates. This coordination supports enforcement consistency along major transport corridors and complements regional fuel-quality standards, helping ensure that vehicles operating across borders meet minimum safety and emissions-related performance expectations. As with emission standards, legal adoption and operational design are carried out by individual member states.
• ASEAN – National Inspection and Maintenance Systems with Regional Policy Coordination (Southeast Asia): The Association of Southeast Asian Nations has no binding regional inspection and maintenance regulation, but regional cooperation encourages gradual convergence in vehicle safety and environmental management practices. All ASEAN member states operate national vehicle inspection systems, with significant variation in inspection frequency, scope, and enforcement rigor. More advanced economies—such as Singapore and Thailand—operate digitally integrated inspection systems closely linked to vehicle registration and road-tax compliance, while other member states are strengthening inspection capacity and coverage. ASEAN policy coordination focuses on knowledge sharing, institutional strengthening, and alignment with Euro-based vehicle standards, recognizing that effective inspection and maintenance systems are essential to sustain emissions and safety benefits across increasingly integrated vehicle markets.

For a vehicle-producing or vehicle-assembling country

When comprehensive data is unavailable, the primary concern is the credibility and enforcement capacity of the national Inspection and Maintenance (I/M) system. The strongest proxy is an institutional readiness profile assessing whether a functioning framework exists for periodic inspection and in-use compliance.

Key indicators include:

Legal mandates for periodic inspection across all vehicle types.

• Inclusion of both roadworthiness and emissions checks, beyond administrative compliance.
• Enforced anti-tampering provisions.
• Linkage of inspection outcomes to registration and licensing.
• Operational capacity to sanction non-compliance.

Absent specific records, I/M maturity can be approximated by reviewing the legal basis for inspections, center accreditation, inspector certification, and the institutional separation between inspection, enforcement, and commercial interests. These proxies indicate the capacity to preserve vehicle performance throughout its operational life.

For a vehicle-importing country

The core challenge is regulatory control after market entry, as fleet performance depends on maintenance over time. Assessment should focus on the I/M system's ability to detect deterioration and tampering, differentiated by import patterns.

• Port-Based Imports: The primary proxy is the post-registration inspection regime. Regulators must assess if mandatory inspections occur shortly after registration and regularly thereafter, with sufficient scope to identify disabled emission systems. This serves as the main safeguard against mis-declared conditions and undocumented modifications in used vehicles.
• Regional Hub Imports: The key proxy is cross-border enforcement and corridor-level inspection. Regulators should evaluate roadside inspections, cross-border certificate recognition, and sanctioning effectiveness. This is critical for landlocked countries, where fragmented I/M systems can encourage regulatory evasion and allow high-emitting vehicles to persist.

2. Vehicle Fleet Profile and Fuel Quality Assessment

The objective is to estimate fleet age, usage patterns, and technology characteristics that determine the relevance and potential impact of I/M systems. Where registries or inspection data are unavailable, proxy indicators can be used. Customs and trade data on used-vehicle imports provide strong signals on average fleet age and likely emission standards. Countries importing large volumes of second-hand vehicles often operate older fleets with higher deterioration risk. Visual roadside surveys in urban areas can estimate the prevalence of smoky or poorly maintained vehicles. These observations can be combined with international survival models to approximate fleet turnover and identify priority segments for inspection. UNECE WP.29 standards offer a global benchmark for classifying fleet technologies.

3. Air pollution levels and health impacts

The objective is to quantify co-benefits by estimating current air quality and associated health burdens, focusing on NOₓ, SO₂, PM, and black carbon. Where monitoring networks are absent, global data can be leveraged—including UNEP/IQAir platform, satellite data from NASA Earth Data, MODIS and TROPOMI, and WHO Air pollution data portal. The State of Global Air report provides country-level exposure and mortality estimates. World Bank and OECD health impact valuation models can assign economic value to the health burden, strengthening policy justification (World Bank, 2016; OECD, 2016).

4. Road transport’s contribution

Road transport’s contribution to urban pollution can be estimated using global inventories like CEDS and EDGAR, which provide sector-specific emission estimates where local data are limited. Modeling frameworks such as COPERT and MOVES offer validated methodologies for estimating emissions by vehicle type and fuel. The AERMOD dispersion model can simulate pollutant concentrations from transport emissions, supporting exposure assessments. Evidence from CCAC (2018) and World Bank (2011) source apportionment studies suggest road transport typically contributes 20–40% of urban PM2.5, with higher shares where older diesel fleets and low fuel standards prevail. 

AQMx Guidance on Air Quality Monitoring

AQMx Guidance on Source Attribution

AQMx Guidance on Emissions Inventory

AQMx Guidance on Health Impact Assessment

Core institutional actions (universal)

These actions establish the legal and institutional foundation for effective I/M systems, regardless of country context.

Map mandates and legal instruments:

Conduct a comprehensive review of existing legislation to identify overlaps, gaps, or conflicts in authority related to I/M. Where mandates are fragmented, formalize roles through Memoranda of Understanding (MoUs) or inter-ministerial agreements to ensure a coherent framework.

Institutionalize coordination:

Embed the central coordination mechanism (for example, a National Clean Transport Task Force) within an existing high-level inter-ministerial platform—such as a National Road Safety Council, Clean Air Committee, Transport Policy Council, or Climate Coordination Body. Anchoring Inspection and Maintenance governance at a senior level ensures political visibility, alignment with national air-quality, road-safety, and climate strategies, and sustained engagement across sectors. Institutional anchoring also facilitates coordination with development banks, donors, and technical partners supporting system upgrades, digitalization, or capacity building.

Convene broad stakeholders:

Beyond core government agencies, systematically engage non-governmental stakeholders that are critical to the credibility, effectiveness, and durability of Inspection and Maintenance reform. This includes academic institutions and technical experts to support system design and evaluation; civil-society organizations and consumer groups to strengthen transparency, accountability, and public acceptance; vehicle operators and fleet owners to provide operational insight; private inspection-center operators and equipment suppliers; and development partners to align technical assistance, financing, and implementation timelines.

For a vehicle-producing or vehicle-assembling country

In producing or assembling countries, the central challenge is ensuring that vehicles placed on the market remain compliant throughout their operational life, and that inspection systems are aligned with increasingly sophisticated vehicle technologies.

Include essential institutions

• Vehicle registration and licensing authorities: Gatekeepers linking inspection compliance to registration, licensing, and operating permits.
• Public or private inspection-center operators: Responsible for conducting inspections and implementing test protocols.
• Enforcement agencies (traffic police, transport inspectors): Essential for roadside checks, sanctioning non-compliance, and addressing tampering.
• Standards bodies and technical institutions: Support inspection protocols, equipment specifications, and inspector certification.
• Development banks and financing institutions: Often required to support investments in inspection infrastructure, digital systems, and workforce training.

Key coordination focus

The task force’s primary role is to align inspection scope, enforcement mechanisms, data systems, and technological readiness, ensuring that Inspection and Maintenance systems remain effective as vehicle technologies evolve and that compliance is maintained without creating bottlenecks, perverse incentives, or regulatory capture.

For a vehicle-importing country

In vehicle-importing countries, the dominant challenge lies in controlling in-use performance, particularly in contexts with high shares of used-vehicle imports and limited oversight at the point of entry.

Include essential institutions

• Vehicle registration and licensing authorities: Responsible for enforcing inspection compliance as a condition for vehicle operation.
• Inspection and maintenance system operators: Central to detecting deterioration, tampering, and safety defects.
• Traffic police and roadside enforcement agencies: Key for identifying non-compliant vehicles in daily operation.
• Vehicle importers, dealers, and traders: Important for aligning post-import inspection requirements and consumer information.
• Regional economic communities and harmonization bodies: Engagement with regional frameworks (for example, ECOWAS, EAC, ASEAN) supports cross-border enforcement consistency and reduces regulatory arbitrage.

The task force’s primary role is to ensure that inspection systems, enforcement practices, and penalties are strong enough to control in-use emissions and safety risks, particularly for older and imported vehicles, and that Inspection and Maintenance systems complement fuel-quality improvements and vehicle standards after market entry. 

Set a clear national objective

Based on the outcomes of the baseline assessment in Step 1, establish a nationwide, periodic I/M system covering all high-impact vehicle categories. The objective should be articulated in terms of coverage, inspection frequency, test scope, and enforcement linkage. To manage implementation, particularly where a majority of the fleet may initially fail, a phased approach is recommended. This can include transitional arrangements such as soft-launch periods with warnings instead of penalties, or repair-and-retest grace periods to allow vehicle owners time to comply without being forced off the road.

Define inspection frequency and phasing strategy

Inspection frequency should be risk-based, reflecting vehicle age, mileage, and technology. International practice supports annual inspections for high-mileage commercial fleets and biennial inspections for newer private vehicles. A graduated implementation timeline is often most effective, initially focusing on high-risk vehicle categories (e.g., commercial and public transport) before progressively including private vehicles. To address the reviewer's concern on phasing, the strategy should prioritize vehicle types known to be high-emitters (like older diesel trucks or two-stroke motorcycles) rather than just vehicle age, though older vehicles within any category naturally warrant more frequent inspection.  

For a vehicle-importing country, I/M systems can be strengthened immediately and deliver rapid benefits. Planning should focus on establishing mandatory periodic inspection soon after vehicle registration and at regular intervals thereafter, particularly for imported used vehicles and commercial fleets.

Define technical scope and inspection content

The national I/M regulation or implementing guidelines should clearly specify mandatory inspection components. This includes emissions-related checks (OBD scans, opacity/idle tests), visual inspections for tampering, verification of emission-control systems, and integrated road-safety checks (brakes, steering, tires).

Assign responsibilities and financing

The planning phase should clearly designate the lead authority for system regulation, the bodies responsible for licensing and auditing inspection centers, and the agencies responsible for enforcement. Financing mechanisms, including inspection fees and earmarked funds, should be identified early.

Synchronize timelines

The expansion of I/M systems should be synchronized with increasing vehicle technology complexity, tightening emission standards, and the availability of compliant fuels. Planning documents should explicitly reference companion fuel quality and emission standards to ensure technical compatibility.  

Institutionalize inter-ministerial coordination

Establish a permanent coordination mechanism, such as a National Vehicle Inspection and Maintenance Task Force or inter-ministerial committee, as described in Step 2: Institutional arrangements.  

Integrate Inspection and Maintenance systems into national strategies

Inspection and maintenance (I/M) systems should be explicitly recognized as core policy instruments within national climate, air-quality, transport, and health strategies. I/M requirements and compliance targets should be reflected in Air Quality Management Plans, Nationally Determined Contributions (NDCs), and Long-Term Low-Emission Development Strategies, particularly where black carbon and other short-lived climate pollutants from road transport are priorities. Embedding I/M in these frameworks strengthens political ownership, enables access to climate and development finance, and ensures real-world vehicle performance is accounted for alongside technology and fuel standards. Health-sector policies should also reflect I/M's role in reducing exposure to traffic-related pollutants, reinforcing the public-health rationale for sustained enforcement. Aligning I/M systems with trade and transport policy not only strengthens national consistency but also supports regional harmonization under frameworks such as ECOWAS, EAC, and ASEAN.

Ensure alignment with energy and fuel quality policies

Effective Inspection and Maintenance (I/M) systems must align with fuel quality policies to ensure inspection outcomes reflect genuine vehicle condition rather than fuel-related constraints. Test thresholds and compliance criteria should be compatible with national fuel sulfur levels. This avoids vehicles failing due to fuel-induced deterioration or passing despite damage from high-sulfur or adulterated fuel.

Coordinate Inspection and Maintenance with complementary transport and regulatory policies

Inspection and Maintenance (I/M) systems must be part of a coherent vehicle life-cycle policy package. Vehicle registration should require valid I/M certification. Roadworthiness and emissions checks should be harmonized. Urban transport policies—such as BRT systems and fleet modernization—should incorporate I/M compliance pathways for legacy fleets. Freight strategies should integrate heavy-duty vehicle inspections, including corridor-specific enforcement. Used-vehicle import policies should coordinate with I/M, creating a unified cycle from entry to lifetime operation; vehicles failing post-import inspection should be prevented from registration.

Integrate Inspection and Maintenance into climate measurement, reporting, and verification and data systems

Inspection and maintenance (I/M) systems generate high-value operational data that can strengthen national measurement, reporting, and verification (MRV) frameworks. Inspection results should feed into emissions inventories, support reporting on PM and black carbon reductions, and enable tracking of compliance trends—improving transparency, supporting NDC reporting, and prioritizing enforcement against high emitters.  

Align Inspection and Maintenance with fiscal and industrial policy instruments

Fiscal and economic policy tools can reinforce I/M objectives: differentiated fees based on inspection performance, scrappage incentives for non-repairable high emitters, reduced fees for public transport, and support for repair and diagnostics industries. Training and certification programs for mechanics strengthen domestic capacity and improve repair effectiveness. 

Define the core technical scope of inspections

National regulations should explicitly define the mandatory scope of inspection, differentiating by vehicle category and fuel type, and specifying which pollutants, components, and indicators must be evaluated during each inspection cycle.

Regulations should require:

• For gasoline/petrol vehicles:
  • idle or two-speed idle tests for carbon monoxide and hydrocarbons, where technically feasible;
  • on-board diagnostics checks for emissions-related fault codes and readiness status;
  • visual inspection for exhaust-system tampering, missing components, or leaks;
  • evaporative-system checks where infrastructure allows.
• For diesel vehicles:
  • standardized opacity testing under free-acceleration or snap-acceleration procedures;
  • verification of the presence and condition of diesel particulate filters, diesel oxidation catalysts, exhaust gas recirculation systems, and selective catalytic reduction systems;
  • on-board diagnostics checks where compatible;
  • visual inspection for excessive smoke, leaks, or exhaust bypassing.
• For heavy-duty vehicles:
  • opacity testing and visual anti-tampering checks as a minimum;
  • optional load-based or engine-based testing where infrastructure exists;
  • electronic control or diagnostics checks where compatible with vehicle technology.
• For motorcycles and three-wheelers:
  • idle testing for carbon monoxide and hydrocarbons where feasible;
  • visual inspection for exhaust tampering, which is common in many markets;
  • basic emissions screening appropriate to local fleet characteristics.

Establish clear and legally binding pass/fail criteria

Inspection regulations must define uniform pass/fail thresholds applicable across all inspection centers. These thresholds should include:

• legally defined limits for opacity, carbon monoxide, hydrocarbons, and on-board diagnostics readiness;
• categorization of failures by severity (for example, immediate failure, repair-required-within-defined-period, advisory);
• provisions allowing thresholds and procedures to reflect local fuel quality and realistic operating conditions.

Uniform criteria are essential to ensure legal defensibility, consistency, and public trust in the system.

Adopt enforceable anti-tampering provisions

Regulations must include explicit and enforceable anti-tampering requirements to protect the integrity of emission-control systems throughout vehicle operation. These provisions should include:

• clear prohibitions on the removal, disabling, or bypassing of diesel particulate filters, catalysts, exhaust gas recirculation systems, and selective catalytic reduction systems;
• procedures for identifying physical tampering, such as missing components, welded bypass pipes, disconnected sensors, or altered exhaust routing;
• mechanisms for detecting electronic or software tampering through on-board diagnostics checks;
• mandatory immediate failure for tampered vehicles and reporting obligations to enforcement authorities.

Without strong anti-tampering rules, the emissions and health benefits of inspection systems erode rapidly in real-world use.

Clarify retesting, appeals, and dispute-resolution procedures

Regulations should clearly define:

• the time allowed for repair following inspection failure;
• conditions and procedures for retesting;
• appeals mechanisms for vehicle owners;
• oversight responsibilities to prevent abuse or corruption.

Transparent procedures strengthen legal certainty and public confidence.

Set binding standards for inspection equipment and calibration

Inspection regulations should specify minimum technical standards for all testing equipment, including:

• accuracy and reproducibility requirements for gas analyzers, opacity meters, and diagnostics tools;
• mandatory calibration intervals and documentation, overseen or audited by the national metrology authority;
• safeguards against manipulation, such as locked firmware or protected settings;
• requirements that only certified suppliers and qualified technicians install or maintain equipment.

These provisions are essential to ensure comparability of results and system integrity.

Define inspection-center operational requirements

Regulations should establish minimum operational standards for inspection facilities, including:

• bay size and layout appropriate to vehicle classes;
• ventilation and exhaust evacuation systems to protect workers and ensure accurate measurements;
• occupational health and safety procedures;
• requirements for reliable electricity supply or backup systems;
• secure information-technology infrastructure for real-time data transmission.

Clear operational requirements reduce safety risks and improve inspection consistency nationwide.

Ensure alignment with fuel quality conditions

Inspection standards and thresholds must be technically compatible with national fuel quality, particularly sulfur content and adulteration risks. Regulations should ensure that testing procedures do not penalize vehicles for fuel-related limitations beyond operator control, while still identifying genuine deterioration or tampering. Alignment with fuel-quality policy avoids false failures and reinforces system credibility.

Regulatory design focus

Inspection and Maintenance regulations should explicitly reflect the technologies present in domestically produced, assembled vehicles, even imported including on-board diagnostics, aftertreatment systems, and electronic controls. As vehicle standards tighten, inspection regulations should be periodically updated to maintain technical relevance. Regulations should clearly state that inspection compliance is a condition for legal operation, closing loopholes that allow high-emitting or unsafe vehicles to remain in circulation.  

Oversight and enforcement  

Authorities must have the legal power to license and audit inspection centers, conduct unannounced inspections, suspend operations in cases of non-compliance, and impose penalties for fraud or systemic failures. Regulations should assign clear responsibility to vehicle owners and operators for compliance. Enforcement authorities must be empowered to deny registration renewal, impose penalties, or remove vehicles from service in cases of repeated or severe non-compliance. 

Design a national communications campaign

Develop a clear, relatable message—such as “Well-Maintained Vehicles, Cleaner Air” or “Vehicle Inspection Saves Lives and Cuts Pollution”—to make I/M visible and relevant. The campaign should explicitly link I/M to improved air quality, road safety, fuel savings, and climate benefits, emphasizing that the system protects the public interest while helping vehicle owners avoid costly breakdowns.

Tailor messages to target audiences

• Policy-makers and legislators: Emphasize that I/M systems are cost-effective, enforceable tools delivering immediate benefits without large capital investments—reducing healthcare costs, preventing injuries, and supporting climate commitments.
• Vehicle owners and households: Focus on practical and visible benefits, such as cleaner neighborhoods, fewer smoky vehicles, safer braking, and lower fuel costs. Explain inspection schedules and compliance steps simply, reassuring owners that inspections identify fixable problems.
• Commercial operators (buses, taxis, freight fleets): Provide detailed guidance on requirements, timelines, and cost implications, emphasizing reduced downtime and accident risk. For mechanics, communicate technical requirements and position I/M reform as an opportunity to professionalize the sector.
• Mechanics and repair shops: Communicate technical requirements and position I/M reform as an opportunity to professionalize the sector.
• Inspection-center staff and enforcement agencies: Clearly communicate expectations on integrity, procedures, and customer service.

Engage trusted messengers

Partner with medical associations, universities, consumer organizations, transport unions, and civil society to communicate evidence-based messages. Independent, locally trusted voices help translate inspection requirements into public-interest outcomes.  

Communicate transparency and progress

Regularly publish data on inspection coverage, compliance rates, common failures, and enforcement actions, protecting individual privacy. Transparency builds trust, deters fraud, and demonstrates consistent application.

Ensure accessibility and inclusiveness

Use non-technical language, visual formats, and local languages. Where literacy or digital access is limited, leverage radio, community networks, and local governments.

Provide clear guidance and customer support

Develop step-by-step guidance on booking, documents, procedures, retesting, and repairs. Establish hotlines, FAQs, and complaint channels, including mechanisms to report fraud or misconduct

Develop integrated communication strategies

Embed Inspection and Maintenance (I/M) systems in national clean-air and road-safety narratives, explaining links between maintenance, fuel quality, emissions control, and public health, particularly in high-exposure urban areas.

Targeted Messaging Focus

Communications should reinforce the role of I/M systems in preserving vehicle performance, safety, and compliance over time, particularly as technologies advance. Messaging must be tailored to key stakeholders:

• Manufacturers, Assemblers, and Suppliers: Emphasize that robust I/M systems protect the reputation and durability of domestically produced vehicles, supporting alignment with international markets by ensuring long-term compliance.
• Policy-Makers and Financiers: Frame I/M as a complementary investment that safeguards the effectiveness of emission standards and maximizes the return on industrial and regulatory investments.
• Public and General Stakeholders: Highlight transparency by regularly reporting aggregated inspection outcomes, including failure rates and common defects for imported vehicles. This reassures the public that I/M systems are effectively preventing unsafe and high-emitting vehicles from circulating, while supporting regional harmonization efforts.

Communication of Milestones

Visible progress reinforces credibility and signals system maturity. Communication strategies should publicize key implementation milestones to demonstrate momentum and enforcement capability:

• System Upgrades: Announce the launch of upgraded inspection procedures, the certification of inspectors, and the integration of on-board diagnostics into inspections.
• Enforcement Campaigns: Launch targeted campaigns explaining new inspection requirements linked to registration and renewal, particularly for imported and used vehicles.
• Compliance & Deterrence: Clearly explain penalties for non-compliance and showcase visible enforcement actions. This helps deter evasion, reinforces system legitimacy, and ensures that the public understands the consequences of failing to meet standards. 

Officially Publish and Operationalize Inspection and Maintenance Regulations 

Implementation begins with formal publication through government gazette or ministerial decrees, giving legal force to inspection requirements, test procedures, pass/fail thresholds, and enforcement powers. Operationalization must clearly define inspection frequency, vehicle categories covered, enforcement start dates, transitional arrangements for legacy fleets, and the respective roles of transport authorities, environmental agencies, inspection operators, and enforcement bodies.

Launch Digital Compliance Registries and Online Reporting Systems 

Digital systems ensure integrity, traceability, and scalability. A centralized compliance registry should record inspection results, failure reasons, retesting outcomes, repair verification, and enforcement actions, linked to vehicle registration databases. Interoperability with registration, licensing, and enforcement systems ensures non-compliant vehicles cannot circulate legally. Public dashboards can summarize aggregated compliance trends.

Create an Open Inspection and Maintenance Transparency Portal 

To build trust and deter fraud, governments can establish an open-access platform publishing aggregated indicators: inspection coverage, failure rates by category, common causes of failure, and enforcement actions. While protecting personal data, regular public reporting enables civil society, researchers, and media to track system performance and reinforce confidence.

Maintain a Technical Helpdesk and Issue Regular Guidance Notes 

A dedicated helpdesk supports inspection operators, enforcement agencies, repair workshops, and vehicle owners by providing authoritative clarification on testing protocols, documentation, and compliance procedures. Regular guidance notes ensure consistent interpretation, reduce unintentional non-compliance, and adapt procedures as vehicle technologies evolve.

Document Lessons Learned and Update Operational Procedures 

I/M implementation is iterative. Authorities should systematically document operational challenges—equipment failures, fraud risks, retesting bottlenecks, enforcement gaps—and use this evidence to update inspection manuals, training curricula, and standard operating procedures. Institutionalizing learning strengthens system resilience and performance.

Coordinate Enforcement Activities across Ministries and Subnational Authorities 

Effective I/M requires coordination across transport authorities (inspection oversight and registration), environmental agencies (pollution control), police (roadside enforcement), and local governments. An inter-agency coordination platform enables shared data access, joint enforcement campaigns, consistent sanctions, and rapid response to emerging risks such as widespread tampering or fraudulent certification.

Establish Transparent Public Reporting Mechanisms 

Regular publication of inspection coverage, compliance rates, high-emitter identification, and enforcement outcomes reinforces accountability and voluntary compliance. Transparent reporting also supports regional coordination by allowing comparison of I/M performance across cities or neighboring countries.

Conduct Systematic In-Use Surveillance

Authorities must prioritize systematic inspection of high-mileage and high-risk vehicle categories, such as buses, freight trucks, and commercial fleets. Inspection frequency and enforcement intensity should be risk-based, informed by mileage, vehicle age, and historical failure patterns.

• Mandatory Periodic Inspection: This is the primary tool for managing in-use emissions, particularly in import-dependent fleets.
• Targeted Campaigns: Routine inspections should be complemented by roadside checks and targeted campaigns focusing on visibly smoking vehicles and known high-emitter categories.
• System Integrity: Randomized oversight of inspection centers is essential to protect system integrity. Accredited inspection results must feed directly into the national compliance registry, with retained records to support audits or appeals.

Monitor Fleet Performance and Repair Effectiveness

Beyond pass/fail outcomes, regulators should analyze inspection data to track recurring failures, ineffective repairs, and signs of widespread tampering. This information supports targeted enforcement, refinement of inspection procedures, and engagement with repair sectors to improve repair quality and availability.

• Data-Driven Adjustments: Authorities should track inspection coverage, failure rates, repair outcomes, and enforcement actions to identify systemic weaknesses and emerging risks.
• Continuous Improvement: Monitoring supports evidence-based adjustments to inspection frequency, test scope, and enforcement priorities, ensuring that the I&M system delivers sustained real-world emission reductions. 

Enforce Compliance through Clear Penalties and Corrective Measures

Enforcement must be credible and consistent. Vehicles failing inspection should be subject to mandatory repair and retesting within defined timelines.

• Escalating Penalties: Sanctions should include escalating penalties—such as registration suspension or immobilization—for repeated non-compliance or confirmed tampering.
• Broad Application: Sanctions must apply equally to vehicle owners, operators, and, where relevant, inspection centers or repair shops involved in fraudulent practices. This ensures accountability across the entire compliance chain.

Link Inspection and Maintenance compliance to vehicle registration and administrative procedures

Inspection and maintenance compliance should be a mandatory condition for vehicle registration, renewal, transfer, and operation. Enforcement systems should ensure that:

• vehicles cannot be registered, renewed, sold, or transferred without a valid Inspection and Maintenance certificate;
• digital or physical proof of compliance is automatically verified during administrative transactions;
• non-compliant vehicles are flagged in registration systems and prevented from lawful operation.

This linkage is the most effective and administratively efficient enforcement mechanism.

Conduct coordinated roadside enforcement campaigns

Roadside inspections are essential to detect expired certificates, tampering, and high-emitting vehicles that evade periodic inspection. Enforcement campaigns should prioritize:

• diesel trucks and buses on major freight corridors;
• public transport fleets operating in dense urban areas;
• high-mileage vehicles such as taxis, motorcycles, and ride-hailing fleets;
• vehicles with visible smoke, excessive noise, or known tampering patterns.

Remote emissions sensing can strengthen roadside enforcement by enabling rapid screening of large identification of likely high emitters for follow-up action. Where legally enabled, authorities can use remote-sensing results to issue repair notices, require confirmatory testing at accredited centers, or prioritize roadside pull-overs for vehicles that repeatedly exceed defined thresholds. This approach is particularly useful where enforcement resources are limited and where a small share of vehicles contributes a disproportionate share of emissions.

Police and transport inspectors should be empowered to verify I&M certificates, issue penalties, and refer vehicles for follow-up inspection or repair.

Apply penalties consistently and transparently

Regulations should define a graduated and enforceable penalty framework, which may include:

• fines for expired or missing inspection certificates;
• repair notices with mandatory deadlines;
• immediate failure or immobilization for severely tampered or grossly polluting vehicles;
• suspension of registration or operating licenses for repeated non-compliance;
• penalties for fraudulent certificates, collusion, or attempts to bypass inspections.

Consistency and transparency in penalties are critical to deterrence and public trust.

Target high-emitter and super-emitter vehicles

Enforcement strategies should explicitly recognize that a small fraction of vehicles often contributes a disproportionate share of emissions. Targeted enforcement—using inspection data, roadside observations, or environmental hotspot analysis—can deliver rapid air-quality gains by identifying and repairing or removing super-emitters from service.

Remote sensing is a technology that is well-suited to super-emitter strategies because it can empirically quantify how emissions are distributed across the fleet and can repeatedly observe high emitters across time and locations. Campaigns like the TRUE Initiative have been designed explicitly to identify categories of high emitters and to support practical program improvements; for example, the São Paulo campaign was launched to provide the environmental authority with a current snapshot of real-world emissions and to help strengthen the city’s vehicle emission control program. In Africa, TRUE has published results from Kampala and launched additional roadside sensing work in illustrating how the same approach can be applied in cities with different I/M maturity levels.

Establish anti-fraud and integrity controls (see Step 5. Standards and Regulations)

Enforcement must extend to inspection centers themselves. Integrity safeguards should include:

• secure access controls for inspectors and inspection software;
• random supervisory audits and undercover checks;
• monitoring of abnormal pass/fail patterns or unusually high throughput;
• clear investigation procedures and sanctions for corruption or collusion.

Without strong integrity controls, enforcement credibility quickly erodes.

Ensure legal defensibility and due process

Enforcement actions must be legally robust. Regulations and procedures should ensure:

• clear documentation of violations and inspection outcomes;
• tamper-proof capture of evidence (such as timestamped photos, inspector identification, and digital logs);
• transparent procedures for appeals and review;
• proportionality and consistency in sanctions.

Legal defensibility protects enforcement agencies and strengthens compliance.

Coordinate enforcement across institutions (see Step 2. Institutional Arrangements)

Effective enforcement requires active coordination across multiple authorities:

• police verify certificates during roadside checks;
• transport authorities manage registration and administrative sanctions;
• environmental agencies identify pollution hotspots and high-emitter patterns;
• customs authorities ensure compliance for imported used vehicles;
• local governments manage urban enforcement zones and public-transport oversight.

An inter-agency coordination platform enables joint operations, shared data, and consistent interpretation of rules.

Communicate enforcement outcomes publicly (see Step 6. Communications and Awareness-Raising)

Public communication reinforces deterrence and trust. Authorities should regularly publish aggregated enforcement statistics, including:

• number of inspections conducted;
• failure and non-compliance rates;
• common causes of failure or tampering;
• penalties applied and corrective actions taken.

Transparency demonstrates that enforcement is fair, consistent, and focused on public benefit. 

Strengthen public-sector capability and institutional leadership 

Ensure that key institutions—particularly Transport, Environment, Police, and Finance—have clear legal mandates, qualified technical staff, and effective decision-making authority. Establish defined career pathways and professional development programs for civil servants working in vehicle inspection, emissions compliance, and regulatory supervision. Retaining institutional knowledge is essential for maintaining inspection integrity and consistent enforcement.

Institutionalize monitoring and data management 

Public agencies must be capable of compiling, interpreting, and acting on I&M compliance data. Develop and maintain interoperable digital platforms that link inspection results, vehicle registration status, and enforcement actions. Capacity-building efforts should include training in data analytics, risk-based targeting of high emitters, and detection of abnormal pass/fail patterns. Strengthening data literacy across institutions improves transparency and supports enforcement credibility.

Institutionalize technical training and accreditation of inspection systems 

Inspection and Maintenance systems depend on a technically competent operational backbone. Establish continuous training programs for inspectors, supervisors, and enforcement officers covering emissions-testing procedures, on-board diagnostics, tampering detection, and fraud prevention. Where inspection centers are licensed or accredited, maintain accreditation under recognized quality-management systems to ensure inspection results are reliable and consistent. Regular refresher training is critical as testing technologies evolve.

Promote regional cooperation and public–public partnerships 

Strengthen regional cooperation through shared training programs, exchange of inspection protocols, and peer-learning initiatives under regional frameworks such as ECOWAS, ASEAN, or MERCOSUR. Regional networks can help pool scarce technical expertise and harmonize inspection practices.

Sustainable financing focus 

Prioritize securing stable, long-term funding for the entire I/M ecosystem, covering governance, center supervision, equipment calibration, data systems, and roadside enforcement. Financing mechanisms should combine national budget allocations with dedicated revenue streams, such as inspection fees, registration-linked charges, and penalties for repeated non-compliance. Where appropriate, establishing a legislatively mandated I/M compliance fund ensures predictable resources for training, audits, digital infrastructure, and public reporting. Crucially, budgetary support must extend to transport authorities, police, and local governments to maintain a robust enforcement presence beyond the inspection centers themselves.

Technical capacity focus 

Capacity building must prioritize advanced training for a broad range of stakeholders, including regulatory staff, inspectors, police officers, and registration authorities. Training programs should cover emissions deterioration, tampering trends, the correlation between vehicle design and in-use performance, and evidence handling for enforcement actions. Close coordination between inspection authorities, environmental agencies, and manufacturers is essential to identify systemic compliance issues early. Strengthening technical capacity at the in-use stage protects the regime's credibility and ensures vehicles remain compliant throughout their operational life, delivering real-world emissions and safety benefits. 

Integrating quality assurance and quality control into monitoring and evaluation

Quality assurance and quality control (QA/QC) are central to credible monitoring, ensuring that inspection results and enforcement actions are technically sound, legally defensible, and comparable over time. A robust QA/QC framework transforms inspection data from an administrative requirement into a continuous performance-monitoring tool.

• Accredited inspection bodies and oversight: Inspections should be carried out by licensed or accredited centers operating under recognized quality-management systems. Regulatory authorities must maintain active oversight through audits and periodic re-licensing.
• Standardized inspection and verification procedures: Adopt nationally standardized inspection protocols covering test methods, pass/fail criteria, and documentation. Standardization ensures that outcomes are consistent and can be aggregated for monitoring.
• Metrology, calibration, and equipment control: Apply legal metrology and calibration requirements to all testing equipment. Regular calibration and maintenance logs are essential to ensure measurement reliability and prevent manipulation.
• Institutional data systems and traceability: Integrate inspection results, re-test outcomes, and enforcement actions into centralized digital databases shared among relevant agencies. This enables traceability and detection of abnormal patterns.
• Competence and continuous capacity building: Sustain QA/QC through continuous training and refresher courses for inspectors, auditors, and regulators to keep pace with evolving vehicle technologies and fraud risks.
• Independent oversight and verification: Establish mechanisms for independent audits or third-party reviews of inspection centers and supervisory authorities. This strengthens public trust and reinforces the credibility of reported data.
• Mandate standardized documentation and data transmission: Inspection systems should be supported by mandatory documentation and reporting requirements, including unique test identifiers linked to vehicle identification numbers and license plates; proof of test integrity (timestamps, inspector ID, center ID); standardized certificates with QR codes or electronic verification; and compulsory transmission of results to a central authority. Centralized data is essential for enforcement, monitoring, and policy evaluation.

Tracking progress through indicators

A clear, well-structured indicator framework is essential to track progress and guide enforcement. Indicators translate complex I/M objectives into actionable evidence for decision-makers. Key principles include ensuring indicators are specific, measurable, achievable, relevant, and time-bound (SMART); embedding data collection in routine government systems; drawing on existing data sources; and ensuring public dissemination.

Key principles: 

• Indicators should be specific, measurable, achievable, relevant, and time-bound.
• Data collection should be embedded in routine government systems, not temporary projects.
• Indicators should draw on existing systems, such as vehicle registration databases, inspection records, roadside enforcement data, and air-quality monitoring networks.
• Public dissemination through dashboards or regular reports supports transparency and trust.

Performance indicators

Example indicators:

• Percentage of fleet with valid I/M certificate.
• Inspection failure rates by vehicle type, age, fuel.  
• Share of failed vehicles successfully repaired and re-certified.  
• Frequency of detected tampering.

Responsible institutions: Ministry of Transport; Vehicle Registration Authorities; I&M Supervisory Bodies.

Implementation notes: Analyze data to identify trends and high-risk vehicle categories. Publish aggregated results in anonymized form.

Enforcement and integrity indicators

Example indicators:

• Number of roadside inspections and certificate checks.
• Number of vehicles penalized or immobilized for non-compliance.  
• Number of audits of inspection centers triggered by integrity concerns

Responsible institutions: Transport Authorities; Police; Environmental Agencies; I&M Supervisory Units.

Implementation notes: Link enforcement data with inspection results to support risk-based targeting of high emitters and strengthen deterrence. Where available, remote-sensing datasets can be integrated with registration and enforcement records to track high-emitter prevalence, deterioration patterns, and the effectiveness of targeted repair and enforcement actions over time.

Air quality and health indicators

Example indicators:

• Trends in roadside or urban concentrations of particulate matter, nitrogen dioxide, and black carbon in high-traffic areas.
• Changes in visible smoke prevalence or roadside opacity measurements along major corridors.

Responsible institutions: Environmental Authorities; Air-Quality Monitoring Agencies.

Implementation notes: Interpret air-quality data alongside inspection and fleet data to assess plausible links between compliance and pollution trends.

Economic and system-sustainability indicators

Example indicators:

• Operating costs of the I/M system relative to coverage.
• Revenues generated from fees and penalties.  
• Cost per high-emitter identified or corrected.

Responsible institutions: Ministries of Finance, Transport, and Planning.

Implementation notes: Track financial performance to assess cost-effectiveness, long-term sustainability, and adequacy of funding mechanisms.

When interpreting results, findings must be situated within broader policy context, as changes may reflect multiple interacting factors. Monitoring and evaluation should support adaptive management, ensuring I/M systems remain effective, credible, and aligned with national air-quality, climate, and public-health objectives. 

Low-cost / institutional measures

Many critical steps toward effective Inspection and Maintenance systems do not require significant financial resources but instead depend on political commitment, legal clarity, and institutional coordination. Governments can establish or strengthen Inspection and Maintenance systems by adopting clear legal mandates that define inspection scope, frequency, pass/fail criteria, enforcement authority, and penalties for non-compliance. Embedding Inspection and Maintenance objectives and milestones within National Air Quality Management Plans (AQMPs), Nationally Determined Contributions (NDCs), and Long-Term Low-Emission Development Strategies (LT-LEDS) ensures policy coherence and sustained political commitment without requiring new spending.

Additional no-cost measures include establishing inter-ministerial coordination mechanisms, typically involving transport, environment, police, registration, customs, and finance authorities, to align inspection requirements, registration rules, enforcement powers, and data sharing. Public disclosure of inspection outcomes, failure rates, and enforcement actions strengthens transparency and deterrence. Communication and awareness-raising activities can often be delivered through existing government channels, such as official websites, public briefings, and social media, without dedicated funding. 

Middle-cost / operational measures

Operational measures generally involve modest but essential investments in human capacity, administrative systems, and oversight tools. Key examples include training inspectors and enforcement officers, strengthening supervisory and audit functions, developing standardized inspection procedures, and introducing basic digital registries linking inspection results with vehicle registration and enforcement actions.

At this level, financing can often be mobilized through routine national budget allocations, cost-recovery mechanisms such as inspection fees, or modest registration surcharges linked to compliance. International organizations and development partners—such as the United Nations Environment Programme, the Climate and Clean Air Coalition, and multilateral development banks—frequently provide targeted technical assistance, training, and limited grant funding to support operational improvements in I&M systems, particularly in low- and middle-income countries. 

High-cost / capital investments

The most financially demanding interventions relate to long-term Inspection and Maintenance infrastructure and system modernization. These may include establishing or expanding nationwide inspection-center networks, investing in emissions-testing equipment (opacity meters, on-board diagnostics tools, digital verification systems), developing secure national databases, and implementing integrated digital platforms linking inspection centers, registration authorities, and enforcement agencies.

In countries with large or dispersed vehicle fleets, additional costs may arise from ensuring geographic coverage, upgrading power and connectivity at inspection sites, and implementing mobile or roadside testing units. In urban areas with dense traffic, investments may also be required for high-capacity inspection lanes or dedicated facilities for public transport and freight fleets.

Financing for these capital-intensive investments typically draws on a mix of public–private partnerships, multilateral development bank loans, blended finance instruments, and climate-finance facilities, particularly where Inspection and Maintenance systems deliver clear climate and air-quality co-benefits through reductions in black carbon, fine particulate matter, and nitrogen oxides. Some countries have established dedicated vehicle inspection or emissions-compliance funds—financed through inspection fees, registration charges, or penalties—to ensure sustained funding for equipment, digital systems, training, and oversight.

This tiered financing framework allows countries to align ambition with affordability, ensuring that the establishment or strengthening of Inspection and Maintenance systems is not delayed by financing constraints, while creating clear entry points for domestic resources and international support. 

Vehicle registration and inspection fees

Modest fees linked to vehicle registration, renewal, or periodic inspection can generate predictable domestic revenue streams to finance:

• inspection-center operations and supervision,
• training and certification of inspectors,
• digital inspection and compliance systems, and
• public-information and awareness campaigns related to Inspection and Maintenance requirements.

Implementation considerations: Inspection-related fees must be designed with attention to social equity and political acceptability, particularly in low- and middle-income countries where vehicle ownership and income levels vary widely. Transparent earmarking of revenues for inspection quality, enforcement, or public transport improvements strengthens public trust and reduces resistance.

Penalties and non-compliance charges

Fines and penalties for expired inspection certificates, repeated failures, tampering, or fraudulent documentation can support:

• enforcement operations and roadside inspection campaigns,
• investigations and audits of inspection centers, and
• targeted interventions for high-emitting or unsafe vehicles.

Implementation considerations: Penalties must be proportionate, legally grounded, and consistently applied. Revenues should be transparently allocated to compliance and oversight functions to avoid perceptions of arbitrary enforcement.

Public–private partnerships (PPPs)

Public–private partnership models can support the financing and operation of:

• inspection and maintenance centers,
• specialized emissions-testing equipment,
• digital booking, reporting, and verification systems, and
• mobile or corridor-based inspection facilities.

Implementation note: Public–private partnerships require robust legal frameworks, clear performance indicators, transparent procurement, and strong public supervision. Contracts must clearly define service standards, data ownership, integrity safeguards, and continuity of service to protect regulatory objectives.

Development partner support

Development institutions often play a critical role in early phases of Inspection and Maintenance systems development, particularly for:

• baseline assessments of fleet condition and compliance,
• design and rollout of inspection systems,
• training of inspectors, supervisors, and enforcement officers, and
• initial enforcement campaigns targeting high emitters.

The United Nations Environment Programme, the Climate and Clean Air Coalition, the World Bank, regional development banks, and bilateral agencies have supported numerous countries in establishing or strengthening Inspection and Maintenance systems as part of air-quality and short-lived climate pollutant mitigation strategies.

Blended finance for inspection infrastructure

Establishing nationwide or high-integrity Inspection and Maintenance systems may require significant upfront investment. Blended finance—using concessional public capital to de-risk private investment—can accelerate deployment of inspection infrastructure and digital systems.

Outcome: Blended finance structures reduce risk for private operators, accelerate system rollout, and demonstrate scalable models for sustainable Inspection and Maintenance implementation.

Results-based climate finance

Results-based finance mechanisms can link payments to verified reductions in black carbon and fine particulate matter achieved through effective Inspection and Maintenance systems, particularly those targeting high-mileage diesel buses and trucks.

Work under the Climate and Clean Air Coalition highlights in-use vehicle emissions control as a priority area for results-based approaches, while emerging analyses from air-quality funding initiatives point to growing interest in linking inspection outcomes with climate-finance mechanisms.

Institutionalising the financing framework

To ensure transparency, continuity, and accountability, financing instruments supporting Inspection and Maintenance systems should be:

• embedded in national law (for example, transport, tax, or environmental legislation),
• governed through multi-stakeholder oversight mechanisms,
• subject to regular public audits and performance reviews, and
• aligned with national transport, air-quality, and climate strategies, including Nationally Determined Contributions and Long-Term Low-Emission Development Strategies.

Evidence from international experience consistently shows that durable inspection and maintenance systems depend on predictable and diversified funding, statutory earmarking, inter-agency coordination, and transparent governance—ensuring that Inspection and Maintenance remains an effective tool for protecting air quality, public health, and road safety over the long term. 

Unequal exposure to transport-related pollution

Women’s exposure patterns to in-use vehicle emissions often differ from men’s due to social roles, employment structures, and mobility behavior, creating gender-differentiated pollution burdens that Inspection and Maintenance policy should explicitly address. Because Inspection and Maintenance systems s directly target high-emitting, poorly maintained, or tampered vehicles, they are a critical tool for reducing exposure where women are most affected.

• Street-level and informal work: Women working as street vendors, market sellers, waste pickers, cleaners, and informal service providers spend long hours near congested roads, bus terminals, and freight corridors where emissions from poorly maintained vehicles—particularly older diesel buses and trucks—are highest. In many low- and middle-income cities, women constitute a majority of informal roadside workers and are therefore disproportionately exposed to emissions from super-emitting vehicles that remain in operation due to weak inspection regimes. Effective Inspection and Maintenance systems that identify and repair or remove these vehicles deliver direct occupational health benefits for women working in these environments.
• Commuting and caregiving responsibilities: Women are more likely to rely on public transport, paratransit, and informal shared vehicles and to engage in trip-chaining that increases time spent waiting at roadside stops or riding older vehicles. Poorly maintained buses, minibuses, and shared taxis often have high in-cabin concentrations of particulate matter and nitrogen dioxide. Strengthened Inspection and Maintenance systems, especially those targeting public and high-mileage fleets, reduce cumulative exposure during daily travel and waiting time.
• Reproductive and child-health vulnerability: Exposure to traffic-related pollutants from poorly maintained vehicles, including black carbon and fine particulate matter, is associated with adverse reproductive and child-health outcomes. Reducing emissions from high-emitting in-use vehicles through effective inspection, repair, and anti-tampering enforcement is therefore particularly important in environments frequented by women of reproductive age and young children, such as markets, schools, health facilities, and residential areas near transport corridors.

Targeted actions for gender-transformative inclusion

Policy and governance

• Inclusive governance: Mandate gender balance in Inspection and Maintenance related governance structures, including national inspection oversight bodies, technical committees, and stakeholder consultations. Representation should include leadership roles and ensure that system design reflects women’s mobility patterns, exposure risks, and access to repair and compliance services.
• Gender-responsive data systems: Require regulators and program operators to collect sex-disaggregated data on participation in inspector training, employment within inspection centers, repair-sector certification, and exposure-reduction outcomes. Gender-differentiated data support evaluation of whether Inspection and Maintenance systems are delivering equitable health and employment benefits.
• Develop a policy narrative: Frame Inspection and Maintenance systems as protecting families, workers, and children by removing the dirtiest and most dangerous vehicles from the road. Emphasizing links between vehicle maintenance, cleaner air, and safer streets strengthens public legitimacy and supports compliance.

Exposure reduction and safety

• Prioritize mitigation in high-exposure zones: Use inspection and enforcement data to prioritize high-exposure areas where women and children are over-represented, such as public transport hubs, markets, schools, and dense residential neighborhoods. Targeted roadside inspections and fleet-focused Inspection and Maintenance interventions in these zones maximize equity and health gains.
• Link Inspection and Maintenance to safer public transport: Align Inspection and Maintenance enforcement with public transport policies that improve fleet conditions and safety. Well-maintained vehicles reduce not only emissions but also risks related to brake failure, fires, and breakdowns, which disproportionately affect women who rely on public and informal transport systems.

Economic and employment inclusion

• Employment inclusion: Actively recruit and train women for roles within I&M systems, including inspection-center staff, supervisors, auditors, data analysts, and certified mechanics. Professionalization of the inspection and repair sector creates formal employment opportunities and helps break gender segregation in technical occupations.
• Affordability and fairness: Design compliance pathways that do not disproportionately burden women-led transport micro-enterprises or informal operators. Measures such as phased compliance, repair vouchers, or access to microcredit for vehicle repairs can prevent I&M reforms from reinforcing existing economic inequalities. 

Disproportionate exposure to transport-related air pollution

• Urban and peri-urban residents in high-traffic zones: Low-income neighborhoods are frequently located near highways, bus depots, and freight corridors where poorly maintained vehicles concentrate emissions. Effective I&M systems that identify super-emitters can deliver rapid air-quality improvements in these communities, even before full fleet renewal occurs.
• Informal-sector and roadside workers: Street vendors, waste pickers, delivery workers, and informal transport operators spend prolonged periods at curbside, where exhaust concentrations are highest. Removing or repairing a small fraction of high-emitting vehicles through targeted I&M enforcement can significantly reduce occupational exposure for these groups.
• Users and operators of aging vehicles: Passengers and drivers of older minibuses, shared taxis, and motorcycles are often exposed to high in-cabin pollution levels due to poor vehicle condition. I&M systems that enforce minimum maintenance and emissions requirements protect both users and operators, who are often low-income and lack access to cleaner vehicles.
• Rural and indigenous communities along transport corridors: Communities located near highways, mining routes, or long-haul freight corridors face chronic exposure to emissions from poorly maintained heavy-duty vehicles. Inspection and Maintenance enforcement along corridors and depots can reduce these impacts, particularly where access to healthcare and regulatory protection is limited.

Key approaches for equitable design of Inspection and Maintenance systems

• Spatial prioritization: Use inspection data, roadside monitoring, and spatial analysis to identify high-emission hotspots and prioritize enforcement where vulnerable populations are most exposed.
• Financial inclusion for compliance: Provide targeted financial mechanisms, such as repair subsidies, scrappage support, or concessional loans, for small operators and informal vehicle owners to meet inspection requirements, preventing exclusion or loss of livelihood.
• Mitigate transition costs: Integrate social-impact assessments into Inspection and Maintenance reforms to understand who bears compliance costs and design mitigation measures, including grace periods, phased enforcement, or targeted assistance.
• Green job pathways: Ensure that training and certification programs linked to Inspection and Maintenance systems reach informal mechanics and transport workers, creating pathways into safer, cleaner, and more stable employment rather than displacement.
• Community consultation and accountability: Engage community leaders, transport associations, and informal worker organizations in the design and rollout of I&M systems to ensure local relevance, trust, and accountability.
• Social-inclusion indicators: Embed equity indicators into monitoring frameworks, such as reductions in emissions in low-income areas, participation of marginalized groups in inspection and repair employment, and access to affordable compliance pathways.

Integrating gender and socio-economic equity into inspection and maintenance systems ensures that in-use vehicle controls reduce inequalities rather than reinforce them—delivering cleaner air, safer mobility, and shared benefits across society while strengthening the legitimacy and durability of Inspection and Maintenance reform.