Sub-problem 1a: Analysis of the existing TWSC intersection

Note in the Exhibit 1-9 how delay and level of service are reported. First, the results are reported for each movement. Then, the results for the minor street approaches are reported. What is the value in showing both results? The results for each movement allow the analyst to see the operation of the intersection at the smallest level. If any one movement is experiencing a high delay, such as movement 10, attention can be paid to resolving that problem. The approach data provides a broader look at the intersection performance and is often useful when comparing the operation of a number of intersections. Finally, you should note that the delay and level of service for the entire intersection is not reported. This is in part due to the assumed zero delay for the major street through and right turn movements and the importance of monitoring the operation of the minor street movements. In any case, it is important to remember that, for an unsignalized intersection as a whole, LOS is undefined.

In summary, a review of the performance characteristics indicates that the intersection is operating acceptably, but in a marginal range with respect to both control delay and queue lengths.

Now that we've completed the analysis of the existing TWSC intersection, we'll proceed to the analysis of the intersection under the proposed signal control.