Traffic Management

This report documents research to determine if the size of electronic regulatory speed signs (ERSS), such as variable speed limit signs, could be reduced without adversely impacting efficiency of driving or safety.

A review of current practice found that the sizes of electronic regulatory speed signs (ERSS) used in Australia are largely similar to those described in Australian Standard AS 1742.4, although some minor differences were identified in a few areas, such as tunnels and managed motorways. Brightness requirements and the minimum number of red annuli from jurisdictions largely follow AS 5156. However, the number of red annuli and the required number of flashing annuli during speed limit changes still vary amongst jurisdictions.

Review of overseas literature and practice concluded that the sizes required for ERSSs are generally equivalent or larger than that of standard static speed signs. Many road agencies tend to recommend larger sign sizes and letter heights for ERSS than for standard static speed signs (e.g. the UK Department for Transport, the US Department of Transportation, NZTA and RMS).

The NS1929 team successfully achieved consensus on the harmonisation of ERSS specifications regarding sign size, sign brightness and sign annulus flashing requirements, with a number of recommendations provided to be considered by Austroads and relevant Australian Standard Committees.