Sub-problem 2c: What is the Level of Service at the Ramp Junction at the Northbound On-Ramp to I-87?

Let's now consider each of these questions:

Should we consider only the vicinity of the junction itself, or are there other areas that we should consider as well? The ramp junction methodology focuses on what is called the merge influence area. The merge influence area is defined as the area from the merge point to 1,500 feet downstream for lanes 1 and 2 of the freeway mainline. It is within this area that most of the effect of the merging traffic into the freeway mainline is observed. For this problem, this area is on I-87 from the point of the ramp merge to 1,500 feet downstream. But we should also consider other parts of the ramp itself. For example, the merge with the U.S. 9 ramp creates some turbulence in the traffic stream as the two ramps come together and drop from two lanes to one in a very short distance. Additionally, we must consider the capacity of the ramps themselves. We'll discuss each of these points later in the sub-problem.

One other point must be made. When we are considering a merge analysis, we need to look at the location of adjacent on-ramps and off-ramps. If these ramps are within 1,500 feet, the effect that they have on the lane distribution of traffic must also be considered. Since there are no ramps within 1,500 feet of this merge area, this issue is not relevant to this problem.