Active ramp metering on critical freeway segments can reduce travel time variability 24 to 37 percent.
Experience with ramp metering in Paris, France.
Made Public Date
02/23/2015

533

Paris
France
Identifier
2015-00979
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Isolated versus coordinated ramp metering: Field evaluation results of travel time reliability and traffic impact

Summary Information

This paper evaluated the performance of active ramp metering strategies used on a 20 kilometer (km) section of the A6W motorway in Paris, France. A comparative assessment was conducted to assess the impacts of isolated (local) versus coordinated ramp meter strategies. The ALINEA ramp meter strategy was used to maintain traffic density within set parameters at specific locations on the motorway, versus the CORDIN strategy which was used to improve overall traffic conditions by adjusting ramp meter timing further upstream to address downstream congestion.

METHODOLOGY

The study area included five on-ramps equipped with signal lights and loop measurement station. Traffic sensors installed at 500 meter increments on the motorway were used to monitor traffic flow, occupancy rate, and traffic speeds during peak periods before and after each strategy was implemented. Data collected from September 2005 through January 2007 were screened to isolate comparable data which included 10, 9, and 11, days for ALINEA, CORDIN, and No Control strategies, respectively. Daily averages were determined from the real data collected from motorway sensors, and a floating car algorithm that was used to calculate motorway travel times and estimate impacts on travel time reliability.

FINDINGS

Both strategies improved peak period travel times and travel time reliability on the motorway. Although CORDIN performed better than ALINEA with respect to the total time spent on the motorway, impacts on travel time reliability were similar.

  • Compared to the No Control case, variability in travel times decreased 24 to 37 percent depending on the measure used.
  • Overall, active ramp metering on the A6A motorway reduced average travel times by three minutes and reduced buffer times required for on-time arrival by 11 to 12 minutes.

Results in the following table were excerpted from the source report.

 

 

 

No Control

ALINEA

CORDIN

ALINEA (%)

CORDIN (%)

Total Time Spent (vehicle*hr)

1399

1263

1231

- 9.8

- 12

Total Travel Distance (vehicle*km)

6266

6141

6260

- 2

0.0

Mean Speed (km/h)

51.7

53.9

57.3

4.3

10.9

 

 

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