| Changeable Message Signs (CMS) are the most visible traffic control devices that provide real-time traffic information about downstream congestion or potential delays to drivers. Their use is intended to modify roadway travel choices through en-route diversion. A high route diversion rate can reduce severe congestion, improve safety, and network performance. However, given the same information, each of the CMS deployment locations are not likely to produce the same level of effectiveness. Under various conditions, based on human, traffic, and geographic characteristics, the CMS vary in their effectiveness. Evaluation of CMS system performance using observed field data was not strenuously researched in previous studies, and no studies have evaluated their effectiveness under various conditions.; To analyze the effectiveness of CMS as it pertains to drivers' route diversion behavior, this study measures the percentage of traffic that diverts to an alternate route during the time the CMS displays a message based on empirical field traffic data under various conditions. A method to estimate travel time from upstream to downstream location using the discrete Inductive Loop Detector (ILD) traffic data was developed and implemented. The sensitivity of the diversion to four different factors: visual observation, familiarity and time constraints, historical or existing traffic conditions, and geographic location were also tested. |
