Sub-problem 4b: Off-Peak Operational Analysis of Alternate Route 7

When we examine the part of the performance table (see below) dealing with ramp operations, we can see one of the results of the d/c ratio near one for the weaving section (section 02). Both the demands on the on and off-ramps are not completely served during this time period. Note for example that the demand for the on-ramp is 2,835 vehicles, while the actual ramp volume is 2,100 vehicles. But there are two points to make here that limit the applicability of these results. First, a limitation in the software used to implement the HCM did not allow entry of 2 lanes to the on-ramp. This produces an unreasonable result of ramp delay and queuing. Second, if this limitation was not present and the results were as shown in the table, the unserved demand during this time period would be transferred to the next 15-minute time period. The same caveat must be applied to the off-ramp results. So, while we can learn an important point about oversaturated conditions (demand exceeds capacity), this example does have a limitation (due to the software) that we need to keep in mind. [*team members: do we want to include a result like this in the guide?*]

These results apply to the off-peak period. In sub-problem 4c, we will consider the peak hour operation of the facility.

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