Engineer's Report

As requested, the City Department of Traffic Safety has conducted an assessment of vehicular and pedestrian traffic at the intersection of Manchaca Road and Prather. I have also personally reviewed the concerns expressed in the constituent letters your office forwarded to me.

While our study found that some of the warrants for a new signal at this intersection are met, installing a signal at this crosswalk would likely result in poor traffic flow and could well cause an increase in accidents. Traffic on Manchaca south of this intersection feeds from a major highway, and installation of a new signal would produce bottlenecks in traffic exiting that highway. Southbound traffic on Manchaca is unimpeded by any signals for over one mile north of this intersection; adding a signal in this location would almost certainly increase the number of rear-end collisions on southbound Manchaca. Therefore, in accordance with federal guidelines (MUTCD, Section 4B.04), we strongly recommend that the city consider alternatives to a traffic signal at this location. These alternatives might include

Installing yellow flashing "high pedestrian activity" signs along north- and southbound Manchaca;
Periodically increasing enforcement activity at the intersection;
Installing physical measures to reduce speeds on the approaches, such as staggered speed "humps" or a raised crosswalk.

A grade-separated crossing is not feasible at this intersection. Drainage requirements make a pedestrian tunnel impossible, and a pedestrian overpass would require at least 15 feet of elevation to allow for bus and truck traffic. This height would make the bridge expensive to build (see attached Cost Estimate) as well as difficult for elderly pedestrians to use.

We feel that the three measures described above, perhaps in combination, would do more to improve safety at the intersection than would a new traffic signal.

Signed,
Fred Barnes, PTOE
Department of Traffic Safety

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