Sub-problem 1a: Traffic Flow Patterns

Speed-Flow
Exhibit 4-8 shows one of the lane-specific speed-flow relationships. It happens to be for Lane 1 Eastbound in the AM peak time period, but it is similar to all the other peak hour plots (i.e., for the other eastbound lane in the AM peak and for the westbound lanes in the PM peak). The mean speed stays at or near its maximum value (55 mph) from free flow conditions to capacity. Moreover, at the high flow rates there are conditions where the speeds are substantially lower as congestion impedes performance.