Monroe County S.I.N. markers

Monroe County posts Structure Identification Number (S.I.N.) markers at bridges and culverts on its county highways, placing them at the start of the structure in each direction of travel. At first they were placed only at fully county-maintained structures (and initially only on the northbound or eastbound sides). Later the county began posting them on structures owned by other agencies over which the county has some maintenance responsibility. These include overpasses crossing railroads, state highways, the New York State Thruway and the State Barge Canal, as well as one bridge owned by Eastman Kodak. Finally, the county inventories and marks several types of non-county structures, maintained by town and village agencies.

The markers use a three-line legend, similar to NYSDOT's reference markers, but the meaning is different. The top line is a two-digit number indicating the town. The numbers are assigned alphabetically, with the City of Rochester following as "town" number 20 (the villages of East Rochester and Scottsville have also been added to the system). The list is as follows:

01 - BrightonImage of S.I.N. marker
02 - Chili
03 - Clarkson
04 - Gates
05 - Greece
06 - Hamlin
07 - Henrietta
08 - Irondequoit
09 - Mendon
10 - Ogden
11 - Parma
12 - Penfield
13 - Perinton
14 - Pittsford
15 - Riga
16 - Rush
17 - Sweden
18 - Webster
19 - Wheatland
20 - Rochester
21 - East Rochester
22 - Scottsville

The second line of digits is the route number. In addition to the numbered county roads, several other codes exist for other types of structures:

000 - Unique code for the Irondequoit Bay Outlet Bridge
333 - Reserved; no known uses of this code
444 - Monroe County Parks Department structures, not maintained by the Department of Transportation
555 - County-maintained structures on town roads (examples are the O'Connor Road bridge over Thomas Creek in Perinton, and the historic Stuart Road Bridge in Chili)
666 - Town-maintained structures (such as French Road over Allen's Creek in Brighton, and Maiden Lane over Round Pond Creek in Greece)
777 - Structures in Greater Rochester International Airport (two exist: the entrance road bridge over NY 204, and the elevated departures roadway)
888 - Reserved, apparently for village-maintained structures (three structures use this code, one each in East Rochester, Fairport and Scottsville)
999 - Reserved, apprently for non-highway structures (the only use of this code currently is for the steam line owned by Monroe Community College, which crosses the Erie Canal on a structure adjacent to NY 15A in Brighton)

The third line gives the distance, in hundredths of a mile, from the route's beginning or from the town line. Distances are reckoned in the usual fashion; i.e., beginning at the south or west end of the route.

These markers began appearing in 1998 or so, and have now been fully deployed around the county. A complete list of S.I.N. structures is available in the Monroe County Bridge Inventory.

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