Evaluation of Changeable Lane Assignment System for Daily Operations (7-2910-1)

The principal goal of this project was to evaluate the operational effectiveness of the CLAS system as a space management tool to optimize daily operations in a primary corridor. This project focused on the operational evaluation of CLAS under recurrent conditions, both before and after CLAS was used to change lane assignments on a pre-timed basis. An analysis of baseline data (turning movement counts) was made to determine candidate sites where daily changes were appropriate. Once candidates for lane assignment changes were determined, traffic operations data necessary for calculating intersection performance measures were collected with permitted double-turn (before) and shared-turn (after) CLAS time-of-day changes, and statistical analysis techniques used to compare before and after traffic operations.|The CLAS concept was installed along the westbound frontage road of US 290 with the anticipation of being used for both incident management and time-of-day operations. The benefits of using CLAS for recurring demand management (at the three interchanges) identified as the most likely candidates for recurring operations were mixed. Improvements in lane balance in some cases were often tempered by increased lane delays, especially at right-turn CLAS applications. Although some reductions in delay and queuing were found, statistically significant reductions in approach delay and queuing were not indicated for the three studied locations. However, this result is considered a function of location and operational characteristics of the intersections studied and not necessarily the effectiveness of the CLAS concept in other locations. Further study is recommended to establish the range of characteristics where time-of-day operations can be most effective. The study of the CLAS concept for incident management will be conducted in FY 1999.