FREEWAY RAMP METERING'S EFFECT ON ACCIDENTS: RECENT ARIZONA EXPERIENCE

An evaluation was conducted that compared accident frequency before and after the installation of ramp metering at nine locations on the Superstition Freeway in Tempe and Mesa, Arizona. Three years of "before" accident data and 3 years of "after" accident data were used. The evaluation considered both changes in number of accidents on the freeway mainline as well as changes in numbers of accidents on the entrance ramps. Ramp metering at the nine locations is in operation only during selected hours of the day. Therefore, it was possible to compare before and after changes in accident frequency for two conditions: periods of the day when ramp metering is in operation and periods of the day when ramp metering is not in operation. On the freeway mainline, accidents during the periods when ramp metering is in operation declined 16%. In contrast, accidents on the mainline during those times of day when ramp metering is not in operation increased 39%. An increase in accidents was observed on entrance ramps. When accidents on both the mainline and the entrance ramps are combined, accidents during periods of ramp metering increased 17%, while accidents during periods when ramp metering was not in operation increased 45%.

• Supplemental Notes:
  • Conference proceedings available only on CD-ROM.
• Corporate Authors:

  Institute of Transportation Engineers (ITE)

  Washington, DC  United States 
• Authors:
  • Upchurch, J
  • Cleavenger, D K
• Conference:
  • Transportation Frontiers for the Next Millennium: 69th Annual Meeting of the Institute of Transportation Engineers
  • Location: Las Vegas, Nevada
  • Date: 1999-8-1 to 1999-8-4
• Publication Date: 1999

Language

• English

Media Info

• Pagination: 10p

Subject/Index Terms

• TRT Terms: Before and after studies; Crash rates; Freeways; On ramps; Ramp metering; Traffic crashes
• Geographic Terms: Mesa (Arizona); Tempe (Arizona)
• Subject Areas: Highways; Operations and Traffic Management; Safety and Human Factors; I73: Traffic Control; I81: Accident Statistics;

Filing Info

• Accession Number: 00770283
• Record Type: Publication
• Report/Paper Numbers: Publication No. CD-006
• Files: TRIS
• Created Date: Oct 22 1999 12:00AM