Publications: Compliance and Enforcement


Effectively enforced vehicle CO2 performance standards are at the core of any effort to realize lower-carbon transport. EU member states should implement supporting policy measures such as emissions-based vehicle taxes, mandates for electric vehicles, and emissions-based road pricing.


Collects and analyzes real-world emissions data from multiple sources in China. The data include emissions of NOx, CO, and total hydrocarbons. from 55 LDVs and 67 HDVs tested using PEMS. The vehicle sample covers a wide range of emissions standards, from China 0 to China 5/V, and vehicle types. 


A comprehensive overview of vehicle remote sensing, an emissions measurement technique which has been used for more than 25 years to evaluate emissions from passing motor vehicles in real-world driving. Reviews technical details of the vehicle remote sensing test method, describes the multiple types of emissions analyses that can be conducted with remote sensing data, and explores areas where remote sensing can supplement emission test methods currently used in the European Union light-duty vehicle regulatory program.


The modifications required by US regulators to VW diesel engines designed to cheat emissions tests are more stringent and more effective than in Europe.


Survey-based summary of regulatory agencies' programs to monitor and enforce compliance with vehicle emission and fuel consumption standards.


Legal brief summarizing public access to vehicle emissions data in the EU and US.


Compares official laboratory-test and on-road nitrogen oxide (NOx) emissions for 541 Euro 5 and Euro 6 diesel passenger cars, representing 145 of the most popular European models.


Evaluates the European Commission’s version of the proposed EU new motor vehicle type-approval framework, where it relates to market surveillance activities, and proposes specific ways in which it could be strengthened.


Examines the potential impact of the EU’s real-driving emissions regulation and ICCT’s proposed modifications on real-world emission factors of new diesel cars and projected passenger car fleet NOX emissions in the EU through 2030.


Identifies key differences in the regulations governing certification of NOx emissions from diesel cars (Euro 6) and trucks (Euro VI) that help explain differences in their real-world emissions performance. Ultimately, an examination of the HDV regulation reveals insights that could be used to improve the LDV regulation.


Reviews provisions of the U.S. and EU regulations that define and prohibit defeat devices, as well as automakers' public statements in the aftermath of VW's admission that it used such defeat devices, as context for evaluating reform proposals.


Analyzes results of emissions tests on 32 Euro 6 diesel passenger cars from 10 different manufacturers. Results show some automakers meeting diesel NOx emissions standards under more realistic driving conditions, while others lag badly.


HDVs conforming to Euro IV and V standards frequently show poor real-world NOx emissions performance. Evidence indicates that new certification protocols in Euro VI resolve this problem, and Euro VI-compliant HDV NOx emissions meet expectations.