Network

This project achieved the objective of consolidating the available research on the impacts of lower speed limits on network operations. It extended this knowledge to bridge an identified knowledge gap regarding urban arterial roads by modelling the impacts of a substantial speed limit reduction on various network performance indicators, including traffic flow indicators, air pollutant emissions, fuel use and casualty crashes during peak traffic periods. Total social cost impacts of speed limit changes were also estimated. The impacts of lower speed limits on traffic flow, safety and emissions increase with the increased proportion of free-flow traffic conditions.