Problem 5: Interstate 87 Interchange

Problem 5 Printable Version

The I-87 interchange is labeled Intersection E in Exhibit 2-1. An aerial photograph of the facility is shown in Exhibit 2-47. The interchange is a partial cloverleaf with three on-ramps and three off-ramps. Southbound, there is a single-lane off-ramp (direct) leading to Route 146 west, a single-lane off-ramp (loop ramp) leading to Route 146 east, and a double-lane on-ramp (semi-direct) for both westbound and eastbound traffic on Route 146. About a quarter of the way along the ramp, traffic from Route 146 westbound joins traffic from Route 146 eastbound to form a two-lane ramp that reduces to a single lane ramp before merging with I-87. In the northbound direction, there is a double-lane off-ramp. It expands to a triple-lane ramp then becomes four approach lanes (two leading westbound and two leading eastbound) at Intersection F. (Exhibit 2-48 is a schematic of the intersection.) There is a single lane on-ramp (loop) from Route 146 eastbound and a single lane on-ramp (direct) from Route 146 westbound. In the picture the entrance to this latter ramp is just west of Intersection F.

The volumes at the interchange are shown for the AM Existing (Exhibit 2-49), AM Without and With (Exhibit 2-50), PM Existing (Exhibit 2-51), and PM Without and With (Exhibit 2-52) conditions respectively.

Analysis Plans: Description of Analyses

Sub-problem 5a: Merges and Diverges on the Freeway

Sub-problem 5b: Route 146 Weaving Section

Sub-problem 5c: Stop and Yield Controlled Junctions

Discussion