Sub-problem 1a: Analysis of the Existing TWSC Intersection

The effects of pedestrians on queues, delay, and even LOS can be dramatic. Exhibit 5-13 shows that, when pedestrians were considered, delays for the northbound and southbound approaches increased very substantially. This correctly reflects the effects of time blockage (21% on three approaches) created by pedestrians at the stop-controlled approaches. The results of this sensitivity analysis also emphasize the importance of considering pedestrian effects in this particular case study, or in any situation where pedestrian volumes can be expected to be significant.

Assuming the geometry and pedestrian volumes remain unchanged from existing conditions, we can perform an analysis on the TWSC intersection with projected traffic levels reflecting the additional volumes generated by the new parking structure. Exhibit 5-14 provides details on queue, delay, and LOS, comparing the current condition with projected traffic and no improvements to the intersection:

Obviously, the effects of the projected additional traffic have been to exacerbate the deficiencies previously identified in Exhibit 5-13. Delays listed as 999 seconds per vehicle represent values where parameters, such as the v/c ratios, drive the delay calculation to very high (>999 sec/veh) values. Such high delay values are not realistic outcomes in the real world, and reflect the reasonable conclusion that demand volumes are likely to change before delays of this magnitude are reached. Also notice that the queue lengths have become substantially greater under the projected future conditions. The numerical analysis results are not as important here as the conclusion that, without mitigation, this intersection is likely to operate unacceptably whether or not additional traffic is realized from the proposed development.