The European Commission has proposed new emissions standards for two and three-wheeled powered vehicles and quadricycles, collectively termed L-category vehicles, as part of a broader regulation that would also cover safety and market surveillance.
From an air-quality perspective the primary objective is to keep constant or reduce the share of total road-transport emissions from L-category vehicl

This white paper summarizes the differences between size-based and mass-based efficiency standards, discusses their relative advantages and disadvantages, and provides guidance on the development of future standards. Specifically, the paper argues that size-indexed standards are more effective in promoting efficient technologies, and more neutral with respect to technology.

This report summarizes several actual and potential congestion-charging programs aimed in reducing motor-vehicle traffic.

This report focuses on heavy-duty natural gas engine technologies that can achieve Euro III, IV, V and VI emission compliance levels. It is based on a comprehensive review of technical literature regarding emission performance &  technologies was performed for compressed natural gas engines of model year 2000 and newer.

This report by ICCT reviews current trends in motorcycle emissions and fuel efficiency technology. Summarizes policy approaches to improve motorcycle emission and energy performance, and discusses what is required to implement these policies.