Evaluating the combined effect of ramp metering and variable speed limits on the French A25 motorway

Despite the large body of literature on active traffic management (ATM) and post hoc evaluation, few are the studies assessing the impact of a combination of ATM strategies implemented in the field. In this paper, we present and evaluate the innovative implementation of a speed regulation scheme combined with local ramp metering. The evaluation is based on field data and the assessment criteria include travel time, travel time variability, capacity and level of service (LOS) under three regimes: (i) no control, (ii) ramp metering, and (iii) ramp metering combined with variable speed limits. Our findings confirm that ramp metering is beneficial to users and suggest that the combination of ATM measures further extends these benefits. However, travel time savings, travel time reliability improvement, and LOS gains are limited to the regulated section and do not affect downstream sections.