Where did the numbers come from for the vehicular volume signal warrants in the MUTCD?
Vehicular volume warrants for traffic signals have been in the MUTCD since the earliest editions in the 1930’s. Changes in those warrants have been occurring almost continuously with each new edition. The original signal warrants came mostly from a consensus of practicing traffic engineers in the late 1920’s as to what volume conditions seemed to result in improved safety and efficiency with signalization. Until the 1970’s, changes in the warrants also reflected only engineering consensus and, as far as is known, were not based on any research. The first warrant changes that had any research basis were the 4-hour and Peak Hour warrants that first entered the MUTCD in the 1978 edition. The graphs in the 1978 MUTCD for the 4-hour and Peak Hour warrants were derived mostly from a very complicated study done for NCHRP in 1976 by KLD Associates, Inc., which evaluated the warrants then in effect and developed additional “new” warrants by utilizing network simulation models.
Related Questions
- With the increase in traffic volumes, the signal warrants are being met more frequently. Is the FHWA considering an increase in volume levels for traffic signal warrants?
- Where did the numbers for the Pedestrian Volume and School Crossing signal warrants come from?
- Where did the numbers come from for the vehicular volume signal warrants in the MUTCD?
