EVALUATION OF MINOR FREEWAY MODIFICATIONS

This study examines three types of relatively minor freeway improvements (ramp additions, ramp relocations and grade-separated ramps) to determine the magnitude of road user benefits accrued. Total benefits were broken down into primary and secondary benefits. Primary benefits are those that accrue to the original target group of vehicles. Secondary benefits are those incidental to the improved conditions (e.g., improved intersection operation when ramp vehicles are eliminated). Delay and travel time data were collected at the site of the ramp additions. Volumes at the new ramp were higher than expected, indicating a latent demand. Annual primary benefits of $162,000 accrued to the users of the new ramps. Secondary benefits in improved upstream intersection operations yielded $7,000 annually. No significant change in accidents resulted. An exit ramp was relocated to eliminate queues onto the main lanes. Main lane conditions improved to produce $10,750 in primary benefits. Because the relocation allowed better lane distribution at the downstream intersection, secondary benefits of $34,500 accrued. Accidents were reduced, but not significantly. A grade-separated ramp was constructed to provide new access between arterials that are too closely spaced for at-grade entrance and exit ramps. An annual savings of $143,000 accrued to the users of the new ramp. Because this study was based on historical data, no analysis of secondary benefits was possible. The improvement reduced the accident rate, but not significantly. (FHWA)

  • Corporate Authors:

    Texas Transportation Institute

    Texas A&M University System, 1600 E Lamar Boulevard
    Arlington, TX  United States  76011

    University of Kentucky, Lexington

    School of Engineering
    Lexington, KY  United States  40506

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Authors:
    • Nordstrom, J A
    • Stockton, W R
  • Publication Date: 1983-8

Media Info

  • Pagination: 70 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00388822
  • Record Type: Publication
  • Report/Paper Numbers: FHWA-TX-83-19+210-11Intrm Rpt.
  • Contract Numbers: Res Study2-18-77-210
  • Files: TRIS, ATRI, USDOT
  • Created Date: Sep 28 1984 12:00AM