Question

# 9. (15 points) There are three routes between O and D, two Traffic Analysis Zones, as shown in the figure below. The total travel demand from O to D is

10,000 vehicle trips during a study period. Table 10-1 shows the attributes for each link, including the capacity, free flow speed,segment length, and BPR formula (or volume-delay function) parameters (a and B). The BPR function is shown below, a) Use the All-or-Nothing method (non-incremental) to determine the traffic assignment on three links. t_{i}=t 0_{i}\left(1+\alpha\left(\frac{v_{i}}{c_{i}}\right)^{\beta}\right) t= Congestion flow travel time on link i; t0i= Free-flow travel time on link i; vi = Volume of traffic on link i per unit of time (flow attempting to use link i); Ci= Capacity of link i per unit of time; a= Alpha coefficient, which was assigned a value of 0.15 in the original BPR curve; and B= Beta coefficient, the exponent of the power function,which was assigned a value of 4 in the original BPR curve b) Use the Incremental All-or-Nothing method to assign the traffic on three links (use 1000 increments).

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