Sub-problem 5b: Future Analysis of 10-Mile Segment of U.S. 95 With Direct Recognition of the Hamlet

Let's discuss each of these issues and how each affects the operational analysis that we are about to complete.

What can be done to assess the future performance characteristics of the one-mile section of U.S. 95 that passes through the hamlet? As development occurs and the speed limit on the one-mile section of U.S. 95 passing through the hamlet drops toward 35 mph, this section of roadway will no longer function as or be perceived as a traditional two-lane highway. Thus, the analysis methodology described in Chapter 20 of the HCM will no longer be directly applicable. This leaves us with the need to find an alternative and reasonable analysis procedure.

For purposes of this discussion, we'll consider three options.

1. We could still apply the two-lane highway procedure, knowing that it isn't directly applicable. If we were to take this approach, then we might have difficulty defending the analysis and, in any case, would have to make several assumptions about passing zones, average travel speed, and other inputs. This is not a desirable option because it relies on an extrapolation of the HCM methodology into an area it was not designed to serve.

2. We could apply a microscopic simulation program that has the capability to model traffic movements on both interrupted and uninterrupted flow facilities. This would normally be the desired option, providing that an appropriate microscopic simulation program can be identified and a sufficient level of expertise, time, and budget are available to employ it and evaluate the results. For this particular sub-problem, we are constrained by the available time and resources within which to conduct the evaluation, so we would prefer to use an alternative analysis procedure that is less time-intensive.

3. We could rely on first principles of traffic flow theory to develop an approach based on intuition, logic, and the various analysis tools that are readily available to us. In fact, the conditions and constraints associated with this sub-problem mean that this is effectively the only option available to us.

Under future conditions, the section of U.S. 95 that passes through the hamlet will effectively operate like an urban arterial segment as described in the HCM, but with segments defined by the unsignalized intersections instead of signalized intersections. In this case, it is the unsignalized intersections that introduce delay to through vehicles on the system. Using a methodology that is consistent in its logic with the analysis procedure for urban streets, we might consider using the posted speed to estimate unimpeded travel time then add to this the delay that through vehicles can be expected to incur at each unsignalized intersection. These two values can then be combined into a single overall estimate of average travel speed on the section of U.S. 95 that passes through the hamlet.