Highways England introduced mandatory variable speed limits on the M25 in 1995 between J10 and J11 to improve traffic flow.  Since then the technology has been refined and variable speed settings are now widely used across the motorway network to improve safety and increase traffic flow (manage congestion).  The underpinning theory started to emerge in the 1950’s with a paper to the Royal Society by Lighthill and Whitham ‘on Kinematic waves II’ in 1955. In this brief talk the interaction of speed and flow will be explored and how this influences the speed set on the gantry.

ABOUT THE PRESENTER

Garry Packer is a control and instrumentation engineer, who started his career nearly 40 years ago on nuclear submarines, After 12 years in the Navy he moved to Strachan & Henshaw where he was involved in commissioning, test and development mostly for the Navy, BNFL and South West Water.  In 2000 he joined the Highways Agency (now Highways England) to run the test facility approving and testing traffic signal optics.  Since then he has worked across a number of operational technology departments at Highways England and currently head the team that reviews the performance and calibration of SMART motorways.