This week's bridge is one of those that could be easily overlooked, the E. 231 St. Bridge over the Bronx River in the Bronx. As with some of the other bridges, I don't know if this is the official name, but somewhere I saw this name given, and the bridge is located between E. 230 and E. 231 St., so it works for me. The other option would be Bronx River Parkway Onramp Bridge, which doesn't sound as nice.
This bridge does indeed carry an onramp to the northbound Bronx River Parkway from Bronx Boulevard. The Parkway of course has no sidewalk and pedestrians are not allowed, and yet there are sidewalks on both sides of this small bridge, hence its placement on this list. The north sidewalk appears to just dead-end at the west end of the bridge, but the south sidewalk (in the foreground of the second picture above) leads to an unmaintained pathway that curves around to head under the bridge. By unmaintained, I not only mean that snow and ice are not removed, but neither are weeds and other plant and trash life and it looks like no one's walked on it in decades (except to throw trash), and once under the bridge it appears to be unpassable due to overgrowth. So not much to run on, but it's there, and it's how I got that neat first picture. I've recently been fascinated by abandoned pathways, dead-end stairways and such, that usually are the mark of some later intrusive highway or other development. There's a lot of it along Riverside Drive and Henry Hudson Parkway in northern Manhattan, but I digress.
I don't know the date of construction of the bridge, but apparently this section of the Bronx River Parkway (from about E. 233 St. to Westchester County) was constructed starting in the early 1920's, so I think it dates from that period. Sections further south weren't completed until the 1950's, but this seems to have features of bridges as originally intended for the Parkway. The Westchester sections of the Parkway were completed by 1925 and it was the first parkway in North America, meaning a high-traffic, limited-access road that shows off the natural features of its environment. The bridges were to be covered in rough-cut stone to appear more natural and blend in with the landscape. By the post-war era, styles had changed. This certainly is a neat little bridge.