The Accuracy of a Speed Profile Estimation Method Combining Continuous and Spot Speed Measurements

The knowledge of the actual operating speed of free vehicles all along a highway (the speed profile) is of a prime interest in safety studies. However, it is not easy to be obtained, for it needs, with traditional methods, a quite high number of travels with a dedicated equipped vehicle. Starting from the knowledge of the actual 85th operating speed profiles on some rural highways, obtained in such a way, the author evaluates in this paper the accuracy of an alternative method, combining in an elementary way few individual speed profiles and few spot speed measurements. An empirical estimation of the resulting error is given, for different numbers of continuous and spot speeds measurements. It appears that with four individual continuous speed profiles and four spot speed distributions, a quite reasonable accuracy may be expected. If such a method is less pertaining than spot speed measurements for studying given points of a road, and not very interesting to know the speed profile along only a single highway, it may be useful to get an idea of the actual speed behavior on each point all over a secondary rural network. But for this, it is very important to carry out the measurements very carefully.

• Corporate Authors:

  Swedish National Road and Transport Research Institute (VTI)

  Linköping,   Sweden  SE-581 95
• Authors:
  • Louah, Gerard
• Conference:
  • Road Safety on Four Continents: 13th International Conference
  • Location: Warsaw , Poland
  • Date: 2005-10-5 to 2005-10-7
• Publication Date: 2005-10

Language

• English

Media Info

• Media Type: CD-ROM
• Features: Figures; References; Tables;
• Pagination: 8p
• Monograph Title: Road Safety on Four Continents, Warsaw, Poland, 5-7 October 2005, Conference Proceedings

Subject/Index Terms

• TRT Terms: 85th percentile speed; Operating speed; Rural areas; Rural highways; Traffic safety; Traffic speed; Traffic speed measurement
• Subject Areas: Highways; Safety and Human Factors; I83: Accidents and the Human Factor;

Filing Info

• Accession Number: 01091499
• Record Type: Publication
• Files: TRIS
• Created Date: Apr 23 2008 9:24AM