Sub-problem 3c: The Southwestern Quadrant

I-787 Southbound Weave
A Type B weave exists in the section of I-787 that starts where the Route 7 ramps join I-787 and ends where the 23^rd Street off-ramp starts, because the traffic from the Route 7 ramps doesn’t need to change lanes to continue southbound on I-787. The I-787SB traffic does make one at least one lane change to exit at 23^rd Street.

There are three lanes in the weave once the merge has occurred and before the 23^rd Street exit ramp starts.

Exhibit 4-61 shows the flows through the weave. Most of the traffic from the ramps crosses over to I-787 southbound. Only 165 veh/hr go to the 23^rd Street off-ramp. One hundred of the vehicles from I-787 southbound go to the 23^rd Street off-ramp. The rest continue south.

The starting point of the weave is ambiguous. The striping at the north end of the weave tries to keep the weave from starting until the lane drop occurs. Field conditions should tell us where the weave starts. It could start as early as where the two-lane ramp joins I-787. It could start as late as where the lane drop occurs and the three-lane section starts. The start varies with the traffic conditions. The heavier the traffic, the earlier the weave starts.