| Most U.S. urban traffic signal systems deploy multiple signal timing plans to account for daily variability of traffic demand (i.e. morning peak, midday, afternoon peak, off peak and night). Groups of signals (belonging to the one zone or section) along an urban arterial, usually operate in a coordinated manner. This essentially means that timing plans change at the same time for all the signals in the group, so as to facilitate vehicle progression of through a series of signals. Good traffic signal timing practices assume a certain level of monitoring and maintenance in order to guarantee that they are efficient in servicing current traffic conditions.;When investigating signal control optimality the most significant evidence to consider is intersection/approach traffic volume. Availability of traffic data is crucial when examining the robustness of signal timing plans for varying daily demand. Flexibility of field signal timing plans to handle day to day and daily traffic demand fluctuations determines whether the designed/optimized signal plan is appropriate/optimal.;The purpose of this study is to establish the methodology to examine the ability of currently deployed signal timing plans to serve traffic demands' diurnal and day-to-day fluctuations, and based on traffic volumes, identify appropriate TOD breakpoints. A methodology developed in this research study is intended to assist traffic signal engineers and operators in developing more robust timing plans which operate well over a broader range of daily and day-to-day demand conditions. This study, also, investigates various methods to identify TOD breakpoints and optimal number of signal timing plans based on the significant amount of collected traffic data. This research included developing an auto-spreadsheet which would enable traffic operators/engineers to observe and evaluate the latest changes in daily demand and based on the historical hourly volumes and identify the most appropriate signal timing plan for the corresponding demand. |
