The goal of optimizing traffic signal control is to strike a balance between throughput and safety. This involves a complex set of measurable criteria for each intersection location and a constant weighing of efficiency versus safety.
It's a scenario almost every driver has experienced: The red light changes to yellow, but you can't comfortably stop in time. This is known as "the dilemma zone."
Design
Street Lighting Contractors can have a great impact on an intersection's safety and efficiency, but only if they are designed properly. FHWA has developed resources to help transportation professionals conduct insightful assessments of signalized intersections and understand the tradeoffs associated with different treatment options.
Start by documenting your intersection. Take photos, video, and use apps to track things like insufficient crosswalk countdown times.
The next step is identifying where an intersection needs improvement. Look for high collision frequencies or rates and a lack of visibility for pedestrians. Then consider an analysis of the intersection's design and operation, including signal phasing. For example, adding phases for left turn arrows may improve the safety of vehicles and pedestrians, but it also reduces the amount of green time available to through traffic, which can lead to congestion and delays. It might be better to look at other ways of handling these conflicts, such as prohibited left turns or geometric improvements.
Installation
When properly placed, signals can help maintain traffic flow and enhance safety. However, they can also contribute to traffic congestion and accidents if improperly located or designed.
Local governmental agencies have processes in place for determining if and when traffic signals are needed. These processes are guided by federal guidelines (Manual on Uniform Traffic Control Devices - MUTCD [This link opens in a new window] and the Manual on Signal Control) that contain criteria (warrants) that must be met before a signal will be considered for installation. These warrants are based on existing vehicular traffic volumes and crash history.
Once the governing agency has determined that an intersection warrants a traffic signal, there are a variety of options available. These may include signal synchronization, which requires a network of pre-timed and/or adaptive traffic signals that work together to maximize vehicle throughput, bicycle and pedestrian movements, and transit operations. This is a more extensive project and typically involves the use of a traffic signal pole.
Maintenance
Traffic signals can do a lot of work to help improve the safety and efficiency of an intersection. They can optimize to maintain safety and flow, prioritize vehicles like emergency vehicles and public transportation and even lengthen the signal times to allow longer buses and trams to make it through an intersection.
Traffic engineers consider many factors and relationships when deciding to install traffic signals at an intersection. Many people may believe that traffic signals are a cure-all for an intersection's problems, but there is a great deal of complexity involved in the decision making process.
Traffic signals require an extensive amount of maintenance and operation. The skills required for a signal maintainer include knowledge of traffic operations, electrical systems (including field installation), utility coordination (both above and below ground), network communications and multiple software programs. Signal maintainers are an indispensable part of the traffic engineering community. They often work in challenging conditions, in the air and around electric systems.
Repairs
In a city that's always evolving and adapting to meet changing needs, traffic signals need to keep evolving as well. Small changes to signal operations can have big impacts on safety and efficiency.
Street Lights Installation intersection capacity, reduce right-angle collisions, and increase vehicular travel speeds and throughput. They're also an important part of pedestrian safety and mobility, enabling safer crossings at intersections.
Signals can be equipped with accessible pedestrian signals, providing audible and vibro-tactile alerts to notify pedestrians when the walk light is activated. The City is actively working to make these enhancements available at high priority locations.
WSB traffic engineers evaluate the existing vehicular and non-vehicular (pedestrian/bicycle) volumes, physical characteristics of the location, and crash history to determine whether a signal will enhance safety and intersection operation at a specific location. They follow nationally accepted guidelines known as “warrants” that experienced traffic engineers have developed based on years of observations and experience. In some cases, it may be more efficient to use a different form of intersection control such as stop signs or roundabouts.
