A PROPOSED HEADWAY DISTRIBUTION FOR TRAFFIC SIMULATION STUDIES

A BRIEF REVIEW IS PRESENTED OF THE SIMULATION OF TRAFFIC FLOW BY THE USE OF DIGITAL ELECTRONIC COMPUTERS. BECAUSE THE COMPUTER CAN ATTEMPT THE GENERATION OF VEHICLES ONLY AT CERTAIN INCREMENTS OF TIME, THE RESULTANT DISTRIBUTION OF HEADWAYS WILL BE DISCRETE RATHER THAN CONTINUOUS. A PROPOSED DISTRIBUTION IS PRESENTED WHICH IS BASED ON A MODIFIED BINOMIAL DISTRIBUTION IN WHICH TWO DIFFERENT LEVELS OF PROBABILITY ARE EMPLOYED. THIS DISTRIBUTION RETAINS THE COMPUTATIONAL EASE OF THE BINOMIAL DISTRIBUTION, BUT INCORPORATES A CONTAGIOUS OR PLATOONING EFFECT AND PROVIDES FOR THE EXISTENCE OF SOME MINIMUM HEADWAY. ITS DERIVATION IS BASED ON THE PREMISE THAT IF VEHICLES TEND TO TRAVEL IN BUNCHES, THE PROBABILITY OF AN ARRIVAL AT EACH TIME INCREMENT IS NO LONGER CONSTANT. TWO PROBABILITIES OF AN ARRIVAL ARE USED. THE PROPOSED DISTRIBUTION INCORPORATES THE PLATOONING EFFECT AND PROVIDES FOR THE EXISTENCE OF A MINIMUM HEADWAY. THE VEHICLE GENERATION PROCEDURE IS SIMPLE TO PROGRAM AND REQUIRES A MINIMUM OF COMPUTATIONAL EFFORT BY AN ELECTRONIC COMPUTER. THE RESULTING HEADWAY PATTERN COMPARES FAVORABLY WITH ACTUAL HEADWAY DATA OBSERVED IN THE FIELD. THIS DISTRIBUTION WAS USED SUCCESSFULLY IN A TRAFFIC SIMULATION STUDY WHICH OBTAINED DELAYS DUE TO VARIOUS TRAFFIC CONTROLS AT INTERSECTIONS.

• Supplemental Notes:
  • VOL 33, NO 5, PP 16-19, 48, 4 FIG, 13 REF
• Authors:
  • Lewis, R M
• Publication Date: 0

Media Info

• Serial:
  • Traffic Engineering, Inst Traffic Engr
  • Volume: 44
  • Issue Number: 1

Filing Info

• Accession Number: 00227137
• Record Type: Publication
• Files: TRIS
• Created Date: Aug 13 2004 6:56PM