Traffic flow responses to unannounced increases in progression speeds of signal systems.

To determine the effect on vehicular traffic when a change is made in the speed of progressively timed signal systems, the time required for the responses to the changes must also be de- termined. This knowledge will be helpful in designing traffic responsive signal systems. This article is a report on a study made of the time required by drivers to adapt to a change in speed of progression from 21 to 33 m.poho and from 33 to 40 m. p.h. on a 1-way urban arterial when the drivers had no knowled- ge of the change. The authors believe that better adaptation could be obtained if information on the changes in the signal system were available to the drivers.