Problem 4: Clifton Country Road 

Overarching Issues
Several overarching issues relate to this intersection. There are some things to discuss before turning to the main purpose of the case study: seeing how to mitigate the impacts from the site-generated traffic.

The first relates to how many time periods we should analyze. That is, what time periods should be considered in examining the intersection’s performance? The answer is several. Clearly, the AM and PM peak hours should be examined. The intersection is part of a major east-west arterial, next to a major freeway interchange. However, the Saturday shopping peak should be examined as well. The intersection is adjacent to three major shopping centers.

We also need to think about whether there’s a peak hour of the generator that’s different from all three time periods, or a peak traffic condition that relates to this specific intersection. For example, we might want to examine the conditions on a Friday afternoon peak hour when the shopping volumes are heavier than they are during the rest of the week. Moreover, we might want to do a separate analysis of the intersection for the Friday afternoon and Saturday midday conditions during the November-December holiday shopping season. The three adjacent shopping centers see a significant growth in patronage during that timeframe. In fact, queues for the westbound left turn can reach as far as the bridges under I-87. The intersection shouldn't necessarily be designed to accommodate these relatively rare events, but it might be appropriate to indicate what the performance is like during these time periods and how many hours during the year the intersection will be in this condition.

This intersection is somewhat difficult to analyze in an isolated fashion, and care is needed. The most important reason is that there are queues on the southbound, northbound, and westbound approaches that can spill back into other facilities. We will analyze those facilities along with the Clifton Country Road intersection to make sure that we’ve taken into account the impacts in the results we present.