Common use of Simulation Model Configuration and Calibration Clause in Contracts

Simulation Model Configuration and Calibration. We set traffic volumes for the approaches based on actual volumes observed by traffic sensors. Some traffic volume data were double-checked by ground-truth video tapes recorded at the test intersections to enhance the reliability of the model calibration process. Traffic flows of intersection approaches generated by the simulation program were reasonably distributed in the range of 50 vehicle-per-hour-per-lane (vphpl) to 1250 vphpl and matched field observed volumes very well. We estimated the passenger ridership on buses on the basis of annual CT ridership (National Transit Database 2004). In our model we selected 12 passengers per vehicle (ppv) as the ridership. The average vehicle occupancy for general-purpose vehicles was estimated to be 1.2 occupants per vehicle, as determined by King County Metro on the basis of field observations (King County Department of Transportation 2002). Additionally, the generation rate of passengers was set as 10 persons per hour (pph) on the basis of the number of boardings at each stop (Community Transit 2005). Other parameters, such as bus headways, locations of bus stops, and so on, were calibrated according to the real values. Figure 7-1 shows a snapshot of the simulation model for the intersection of 164th Street and 36th Avenue. We also calibrated the traffic control settings of the simulation model by using actual traffic operation parameters and control plans. Internal parameters for the simulation model were properly adjusted to ensure the model’s appropriateness to the corresponding application. After the simulation model was properly calibrated, we conducted a six-hour simulation test: three hours for TSP on and the other three hours for TSP off.