Interchange of the Week
Monday, 27 October 2003
I-81 & I-481, Syracuse
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Orientation: Interstate 81 runs from bottom to top at left, while Interstate 481 runs toward the right from it. East Brighton Avenue runs from bottom to top alongside I-81. The surface road parallel to I-481 is called Rock Cut Road west of the interchange ramps and Jamesville Toll Road east of them. Outside of the Syracuse city line (right of center) this road is Onondaga CR 103. The New York, Susquehanna & Western Railroad runs along I-481's north side.

Exit numbers: Exit 16A from I-81 is for I-481 north to De Witt. From I-481 southbound, Exit 1 is for Brighton Avenue; northbound, it is for Rock Cut Road and Brighton Avenue. Typical of Interstate termini, the I-81 interchange is unnumbered from I-481.

The interchange: The interchange between I-81 and the southern terminus of I-481 is an unusual mix between a directional-T (see Week 45, bottom) and a semi-directional T (see Week 21, Exit 8). Specifically, the ramp from I-81 southbound to I-481 is directional (it branches to the left for a left-turn movement) while that from I-481 to I-81 southbound is semi-directional (it approaches I-81 from the left but joins it on the right). This is likely due to the proximity of the office complex on the southbound side of I-81.

On I-481, the Brighton Avenue interchange is functionally equivalent to a folded diamond (see Week 59) with two notable features. First, the entrance ramp on the southbound side feeds into the I-81 northbound ramp; there is no access from Brighton Avenue to I-81 southbound at this location. Such access is available at the next northward interchange, where there is, furthermore, no access to I-81 northbound from Brighton Avenue. The second feature is that the northbound ramps are modified into a pair intersecting Rock Cut Road, which completes the connection to Brighton Avenue. Note the channelization of these ramps where they intersect the surface road.

I-81, I-481 & NY 481, North Syracuse
US 11
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Orientation: I-81 runs from bottom to top. I-481 enters at right, becoming NY 481 as it crosses I-81. US 11 runs along the left edge, and South Bay Road (CR 208) runs from bottom left to top right. East Circle Drive runs between US 11 and South Bay Road, past the Penn-Can mall on the north side of NY 481; it is reference route 931H from US 11 to the stream just east of the interchange ramps. Bear Road runs along the south side of NY 481; it is reference route 930J east of US 11. The Village of North Syracuse is at lower left.

Exit numbers: From I-81, Exit 29 is for I-481 south to De Witt, and NY 481 north to Oswego and North Syracuse. From I-481/NY 481, Exit 9 is for I-81 to Syracuse and Watertown. Exit 10 on NY 481 is for US 11 to North Syracuse (via Circle Drive or Bear Road).

The interchange: The junction of I-81, I-481 and NY 481 is a full cloverleaf, the most basic type of freeway-to-freeway interchange, albeit an outmoded form due to the weaving motions inherent in the design. Adjacent to it, on NY 481, is an interchange with US 11 and South Bay Road (the latter being omitted from signage on the freeway) via Circle Drive and Bear Road. Leaving aside South Bay Road, this interchange is also theoretically a folded diamond, with both ramp pairs intersecting parallel surface roads (as with Rock Cut Road above) which thus complete the connection. Because of this, the State has assumed responsibility for parts of these roads to ensure the adequacy of the connections. Access to and from South Bay Road, while beneficial, is incidental to the interchange's abstract function. Notice again the channelization of the ramps where they meet Circle Drive and Bear Road.

David Pagano writes of the I-81/I-481/NY 481 interchange:
"Before I-481 was constructed between here and I-90 in the mid-1980s, NY 481 ended with a standard trumpet interchange at I-81 built in anticipation of I-481. Remove the western loop ramps and the ramps to the southeast in the picture and you have it. Going further back, before the existence of NY 481, the divided highway from the trumpet interchange connected to Bear Road. Note that Bear Road is divided with four lanes just before sweeping to the south and reducing to two lanes at the same point NY 481 curves to the north. And going further back than that before any of the highways were built, Tuller Road, the small east-west road just north of the I-81 South to NY 481 ramp, continued straight across South Bay Road, through the present rights of way for NY 481 and Bear Road, and connected with its western half in North Syracuse."

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