Traffic signals don't always prevent accidents. They are not always an asset to traffic control. In some instances, total accidents and severe injuries increased after signals were installed. Usually, in such instances, right angle collisions were reduced by the traffic signals, but the total number of collisions, especially the rear-end type, increased.
There are times when the installation of signals results in an increase in the number of pedestrian accidents. Many pedestrians feel secure with a painted crosswalk and a red light between them and an approaching vehicle. The motorist, on the other hand, is not always so quick to recognize these "barriers."
When can a traffic signal be an asset instead of a liability to safety? In order to answer this, traffic engineers have to ask and answer a series of questions:
- Are there so many cars on both streets that a traffic signal is necessary to clear up the confusion or relieve the congestion?
- Is the traffic on the main street so heavy that drivers on the side street have difficulty crossing?
- Would the total delay to drivers be improved by a traffic signal, or is a four-way stop an acceptable alternative?
- Are there so many pedestrians trying to cross a busy main street that confusing, congested or hazardous conditions result?
- Are signals at this location going to help drivers maintain a uniform pace along the route without unnecessary stopping?
For additional questions about traffic signals or other traffic-calming measures, please contact Engineering at 650-616-7065.