Control strategy options for VMS-QUO VADIS

The primary objective of QUO VADIS is to establish how variable message signs (VMS) are best managed to give high quality information and guidance to drivers and to improve the capacity of a road network. The author describes how the four alternative approaches being investigated within QUO VADIS are: a plan selection approach (developed by OFTPA) based on a pre-established library of plans identified by rule of thumb; a plan selection approach (developed by TRL) that utilises the MCONTRAM network traffic model to develop a library of plans; a feedback approach (developed by Technical University of Munich and INRETS) derived from automatic control theory and leading to traffic responsive control based on current traffic measurements; and an expert system approach OPERA (developed by the French Companies ISIS and STERIA) combining real-time forecasting and pre-established expert rules.