Ramp metering and dynamic speed limits shown to reduce congestion and shorten average travel times by about 2.5 minutes on a 7.8 km stretch of the A25 motorway in France.

Researchers conducted am evaluation of two European Active Traffic Management (ATM) strategies.

September 4-6, 2017
Englos; Nord; France

Summary Information

Researchers conducted am evaluation of two Active Traffic Management (ATM) strategies that were implemented during morning peak hours, on working days, on a section of the A25 motorway. The first strategy consists in ramp metering only and the second associates RM and variable speed limits. The evaluation was based on data collected before and after the implementation of the two strategies.

Three Databases were used to assess the effectiveness of each ATM scheme:

Travel time data. Travel time were collected on working days of the following months:
  • May, June, October, and November 2015–no control. In total, 40 days.
  • February and March 2016 –Ramp metering only. In total, 11 days.
  • March and April 20th, 2016 –Ramp metering and dynamic speed limits. In total, 31 days.
Traffic data. Conventional traffic data coming from inductive loops (flow, occupancy, speed)

Contextual Data. Contextual data offer additional insight to statistical analysis. Researchers crossed traffic data to weather data and other reports coming from the motorway operator (incidents, accidents, planned work, etc.)


Average travel time was reduced with each implementation of ATM measures. The travel time differences of 95 seconds (when passing from No Control to Ramp Metering) and 56 s (when passing from Ramp Metering to Ramp Metering + Dynamic Speed Limits) are statistically significant at the 95 confidence level. Researchers thus conclude that the combination of the two ATM measures reduces travel time on the 7.8 m control route by about 2.5 minutes.

Distribution of level of service (LOS) during morning peaks showed a reduction in congestion:
  • From 7-8am, congestion duration is reduced 28 percent to 18 percent
  • From 8-9am, congestion duration is reduced 52 percent to 30 percent
  • From 9-10am, congestion duration is reduced 16 percent to 8 percent
  • From 10-11am, congestion duration is reduced 4 percent to 0 percent.

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

Author: Cohen, Simon et al.

Published By: 20th EURO Working Group on Transportation Meeting

Source Date: September 4-6, 2017



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Benefit ID: 2018-01304