The origin of this bridge is an interesting history. In the late 1800's it was the site of a low footbridge, when this stretch of the Harlem River was too shallow for navigation. A few factors caused a change. Primarily, the northern Harlem River was dredged to allow for shipping from the East River to the Hudson, so the footbridge would have to be removed and some sort of drawbridge constructed. This dredging project, in 1891, is also what separated the Marble Hill neighborhood from Manhattan Island further upriver around 225th St. and Broadway to create the Harlem River Ship Canal. To this day, Marble Hill is the only piece of Manhattan that is attached to the mainland and the Bronx. In addition, the subway line (currently the 1 train) was being extended into the Bronx at that location, and the swing bridge that was built there in 1895 was deemed unsuitable for the train, so the span was removed, floated downstream on a barge and put in place between 207 St. in Manhattan and Fordham Road in the Bronx, and it opened for traffic on January 8, 1908. Because of structural and load concerns, the bridge was rebuilt between 1989-1992, with efforts made to replicate the original as much as possible.
The University Heights Bridge is a swing, or rotating, drawbridge, with a 264-foot span and a clearance of 24 feet above the water. It has a sidewalk on the south side connecting 207th St. with Fordham Road, and carries four lanes of traffic. Immediately on the Bronx side are the University Heights station for Metro North's Harlem line and access ramps to the Major Deegan Expressway.
The bridge is names for the University Heights neighborhood of the Bronx to (or from) which it leads, which itself is named after the Bronx campus of New York University which was established there in 1894 (although it is now Bronx Community College). University chancellor Henry Mitchell MacCracken was trying to establish the name University Heights for the surrounding neighborhood, so he was urging the naming of the bridge as such.
Runners must share the 6-foot wide sidewalk with pedestrians and bikers, but it's seldom congested. I've personally never seen the drawbridge closed, but it is operational. For me, it is a nice connection between the Inwood neighborhood of Manhattan to Fordham Road and the Pelham Parkway past the Bronx Zoo and Botanical Gardens and on out toward City Island. Or by turning north on Sedgwick Ave. a few blocks uphill after crossing into the Bronx, it provides an alternative route to Van Cortlandt Park (alternative to Broadway).