A system has been devised whereby drivers are given warning if they are following the car ahead of them too closely. The Following Too Closely (FTC) Monitor System as it is called, was designed as a result of research studies that show that following too closely is a contributing factor in a good number of accidents. The system consists of sensors buried in the pavement, and an infrared light source connected to a sign which triggers a flashing Danger if the gap time between two vehicles between .70 and 1.25 seconds. A flashing Violation message occurs if the gap time is less than Transportation Research Council installed monitors on a four-lane undividied section of Route I. The objective of the research was to evaluate the effects of the monitors on accidents, vehicle spacings, speed and driver behavior. The results of the before and after analysis are: 1) the amount of actual accidents, both injury and property damage types, was less than predicted; 2) the reduction in total accidents was evenly distributed among all accident types, not just rear end crashes; 3) monitors in suburban areas were more effective in accident reduction than those in rural areas; 4) monitors did not significantly affect traffic speeds; 5) monitors greatly reduced following-too-closely for a 3 to 5 month time period; 6) after 9 months, monitors began to lose effectiveness; 7) as a result of issuance of warning citations in the 10th month, accidents decreased and spacings increased; 8) there was no evidence that drivers reacted in an erratic manner to the Danger & Violation signals; 9) based on a one-year comparison, the benefit/cost ratio of the system was 2.25 to 1.

  • Corporate Authors:

    Institute of Traffic Engineers

    2029 K Street, NW
    Washington, DC    20006
  • Authors:
    • Parker Jr, M R
  • Publication Date: 1976-7

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 56-59
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00142045
  • Record Type: Publication
  • Report/Paper Numbers: HS-019 180
  • Files: HSL, TRIS
  • Created Date: Jan 16 1977 12:00AM