Interchange of the Week
Monday, 9 April 2001

I-87, US 9, NY 7 & NY 9R, Latham

NY 2

A full-size image (687 KB) is also available.

Orientation: Interstate 87 runs bottom to top at left, while US 9 is the surface road running bottom to top at right. The NY 7 freeway enters at right, ending at I-87; the NY 7 designation continues south on I-87. At bottom left, NY 7 continues westward (toward Schenectady) along the Troy-Schenectady Road, while to the east (toward Troy) runs NY 2, which has its western terminus here. Partially visible at bottom is the interchange between US 9 and NY 2, featured in Week 6. NY 9R runs east (right) from US 9, just north of the NY 7 freeway. Sparrowbush Road runs left to right at center, passing over I-87 and ending at US 9.

Exit numbers: From I-87, Exit 7 is, coincidentally, for NY 7 eastbound, along with US 9 and NY 9R. Exit 6 is for NY 7 west and NY 2 east.

The interchange: As in several other cases, an interesting situation arises here with the juxtaposition of otherwise ordinary interchange forms. The NY 7 freeway's interchange with US 9 overlaps its junction with Interstate 87. The interchange with US 9 consists of a folded diamond, where the exit ramps in each direction form cloverleaf-style loops. This configuration accommodates existing properties and intersecting local roads: Sparrowbush Road intersects US 9 opposite the eastbound interchange ramps; likewise NY 9R and the westbound ramps. The eastbound ramps are further compressed to avoid an adjacent residential street.

The terminus of the NY 7 freeway at I-87 takes the typical "trumpet" form. However, the NY 7 exit to northbound I-87 actually falls in advance of the ramps for US 9 and NY 9R, which it passes beneath. Furthermore, a separate entrance to I-87 northbound carries traffic from US 9 and NY 9R. Along I-87 southbound runs a collector/distributor roadway, which sorts traffic entering and exiting for Exits 6 and 7.

Immediately to the south is Exit 6, the Troy-Schenectady Road. Before the NY 7 freeway was constructed in the 1970's, NY 7 remained on the Troy-Schenectady Road all the way eastward to Troy, while NY 2 had its terminus in downtown Albany. Today, eastbound NY 7 has a short overlap of I-87 northbound, as it enters the mainline here and leaves it at Exit 7. In the reverse direction, however, there is technically no overlap: NY 7 westbound follows the collector/distributor roadway of I-87, but never enters the mainline. A slip ramp is visible from the collector/distributor roadway to the I-87 mainline, allowing entry for traffic from the NY 7 freeway without passing through a traffic signal at Troy-Schenectady Road.

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