Obviously, a traffic signal will cause traffic on the major road to stop at times when it previously did not have to stop. This often contributes to traffic congestion. In some situations, a signal also may force vehicles on the side street to wait to cross the major road even when gaps in the traffic stream would have allowed them to cross sooner.
Experience has shown that, while reducing angle crashes, the installation of a traffic signal typically will increase the frequency of rear-end collisions that occur at an intersection. The trade-off of additional rear-end collisions for fewer, but normally more severe, angle crashes are acceptable where numerous angle crashes have occurred. However, where there is no history of angle crashes to offset the likely increase in rear-end collisions, the overall safety of the intersection likely will deteriorate if a signal is installed.
Where a signal is not justified, the unnecessary delay frustrates drivers. They become more apt to disobey the signal and to increase their speeds to avoid stopping or to make up for lost time after stopping. Noise from traffic stopping and starting at a signal can be irritating in both residential and commercial areas. An inappropriate signal also can cause some drivers to use alternate routes, thereby increasing traffic on lower volume residential streets. Additionally, a signal located too close to another signal on a two-way road prevents a beneficial signal progression.
Traffic engineers and others responsible for the safe and efficient movement of traffic are continually monitoring traffic movement and usually are among the first to spot an intersection problem before it becomes a major one. Public input is also quite valuable.
Keep an open mind. Simply describe the situation or problem rather than request or demand that a signal be installed. In many instances, other solutions will yield more favorable results. Sometimes, no change is needed.
The SHA and the larger local jurisdictions have traffic engineering units that routinely address these matters. If the intersection is outside Baltimore City and involves a MD, Interstate, or US numbered route, contact the SHA District Office listed in this pamphlet for the County where the intersection is located. Otherwise, contact the local traffic engineering agency or, if none, the roads, street, public works or law enforcement agency responsible for traffic operations in the city or county where the intersection is situated.
707 North Calvert Street
Baltimore, Maryland 21202-3601
Main Business Line – 410-545-0300
Safety Campaigns – 1-800-323-6742
For emergencies, call MDOT SHA's Statewide Operations Center at 410-582-5650.
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