Measuring the effectiveness of ramp metering strategies on I-12.

Details

• Creators:
  Ishak, Sherif ; Codjoe, Julius ; Osman, Osama A. ; Russell, Marlene ; Rodriguez, Jose
• Corporate Creators:
  Louisiana State University. Department of Civil and Environmental Engineering
• Corporate Contributors:
  United States. Federal Highway Administration
• Subject/TRT Terms:
  • Ramp metering
  • Interstate highways
  • Highway traffic control
  • Traffic data
  • Speed data
  • Traffic congestion
  • Travel time
  • Level of service
• Publication/ Report Number:
  FHWA/LA.08/507
• Resource Type:
  Tech Report
• Geographical Coverage:
  Louisiana
• Corporate Publisher:
  Louisiana. Dept. of Transportation and Development
• Abstract:
  Ramp metering is one of the successful traffic control strategies in the area of active traffic and demand management. This study evaluates the ; effectiveness of a fixed time ramp metering control on the day to day operation of traffic over two segments of I-12, seven miles apart, in Baton ; Rouge, LA. Traffic data were collected and analyzed using MIST (Management Information System for Transportation) detectors at one segment, ; and DCMS (Data Collection and Management Service) detectors at the other segment. The assessments undertaken include a comparative speed ; analysis, travel time savings analysis, level of service analysis, and speed contours analysis of the conditions before and after deployment of the ; ramp metering. For the MIST segment, the statistical analysis showed that for the eastbound PM peak period, 47% of the time there were significant ; speed increases of 7 mph, but 12% of the time there were significant speed decreases of 17 mph. For the westbound AM peak period, significant ; speed increase of 5 mph were observed 43% of the time while significant speed decrease of 7 mph were observed 29% of the time. The speed ; contours analysis supported these findings with more areas of congestion observed in the westbound AM peak period than was observed in the ; eastbound PM peak period. The travel time analysis showed mixed results of reduced and increased travel times depending on which weekday was ; being analyzed. The level of service results suggests an overall deterioration of traffic conditions for both peak periods. For the DCMS segment, ; however, there was an average decrease in speed from 61.91 to 58.37 mph for the eastbound PM and 53.78 to 49.06 mph for the westbound AM ; peak periods. The speed contours showed increased areas of congestion for both peak time periods, and analysis of travel time savings showed ; overall increases in travel times for both peak periods. The level of service results supported the findings, showing worsened LOS distributions for ; both peak periods. It should be noted, however, that the analysis for the DCMS segment did not account for the effect of the on-going construction ; work between O’Neal Lane interchange and Walker/La. 447 interchange, which started as early as 2009. It is possible that the presence of the ; construction zone may have impacted the traffic conditions and obscured the benefits of ramp meters. This is because the construction work ; schedule overlapped with the analysis time period. For both segments, it was not possible to isolate the effect of incidents on traffic conditions when ; measuring the performance of ramp meters since incident logs were not available at the time the analysis was done. While the fixed time operation ; of the ramp metering system on I-12 was effective to some extent on one of the western segment of I-12, the study recommended further ; investigation to determine if other ramp metering strategies would be more effective. This includes both local and coordinated demand responsive ; ramp metering systems. Furthermore, due to the confounding effect of the work zone in the eastern segment of I-12 and the current fixed time ramp ; metering system, the study recommended further comparative analysis by turning the ramp meters on and off for a few days to determine the effect ; on traffic conditions. This practice was followed in other studies such as the one in Minnesota.
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• Format:
  PDF
• Funding:
  LTRC Project Number: 11-2SS;State Project Number: 30000177
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/26694/dot_26694_DS1.pdf
• File Type:
  [PDF - 3.51 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:0d412f02422f5e20fe17f5d8bac9eced85e8b3f43b9071be45d4a3db2df6c10cd5861070564685eb47c4f323eb375e4ad49bb576b7230484e85ff93fae70dcfc