Traffic Signals

The Department of Public Works maintains all aspects of traffic signals from changing bulbs to resetting the timing. If you notice a malfunctioning traffic signal, contact the Traffic Department to report it to Public Works for inspection and repair. Street signs are constantly being updated. Public Works repairs/replaces signs, as needed, due to accidents and/or weather. If you notice a problem with a traffic sign such as tree limbs in the way, graffiti, a missing sign, etc., contact the Traffic Department to report it to Public Works for inspection and repair. The Streets Division installs all new signage at the request of the Traffic Coordinating Board. Parking meters are also installed and maintained throughout the downtown area of the city's business district.

Many of the City's traffic signals are coordinated to allow for more efficient movement of traffic. The goal of signal coordination is to get the greatest number of vehicles through a corridor with the fewest stops in the safest and most efficient manner. It would be ideal if every vehicle entering a corridor could proceed without stopping. This is not possible, even in the most well-designed system.

Signal coordination is the synchronization of two or more intersections along a section of roadway and is a technique that is used to improve overall intersection operations usually quantified as the reduction in overall intersection delay.

Coordinating traffic signals involves connecting them so they work together to provide motorists with green lights as they progress down the street. The traffic on the major street forms "platoons" of cars that pass through the intersections when the signals at those intersections are green.

Signal coordination is utilized to improve the capacity of the existing street system by reducing delays and stops. Furthermore, coordination tends to reduce accidents. Optimizing the timing of coordinated signal systems in order to provide smooth, continuous platoon progression is regarded as one of the most cost-effective traffic management actions through reduction in stops, delays, fuel consumption, and exhaust emissions.

This sounds like a simple task to accomplish. With a one-way street and few arterial cross streets, it is simple. But the following complications can make the calculations become quite difficult:

• A two-way street
• Arterial cross-streets close together
• A route that turns
• Left-turn signals
• Short blocks

Signal progression for optimized systems faces the dilemma of competing goals of minimizing delay, maximizing capacity, and providing good progression to avoid complaints about poor signal timing from the public.

The higher volume roadway is favored over the side street when traffic signals are coordinated. In this situation, side-street traffic may experience an increase in number of stops and/or longer stops. However, the benefit gained by traffic on the higher volume roadway exceeds the degradation in operations experienced by the side-street traffic, and overall intersection operations are improved. In simple terms: the majority rules.

Signal coordination provides a means by which the sequence (beginning and ending) of green lights is established along a series of traffic signals to allow for the uninterrupted flow of traffic between these traffic signals. Signal coordination is most typically used along heavily traveled arterial streets with a frequent presence of traffic signals.

The goal of signal coordination is to get the greatest number of vehicles through a corridor with the fewest stops in the safest and most efficient manner. It would be ideal if every vehicle entering a corridor could proceed without stopping. This is not possible, even in the most well-designed system. Therefore, with signal coordination, the heaviest traffic movements are given precedence over the smaller traffic movements.

Benefits of Signal Coordination

• Reduces overall stops and travel delays.
• Allows for large groups of vehicles to efficiently flow through a series of traffic signals without stopping.
• Reduction in the number of stops reduces vehicle emissions and thus improves air quality. Most of the vehicle emissions occur during acceleration (stop-and-go traffic).

Disadvantages of Signal Coordination

Side street traffic typically experiences a longer wait time.

In the development of signal coordination, we have to manage the competing interests of providing continuous flow of traffic on the arterials, providing adequate time for pedestrians to cross the street, and minimizing the wait time for side street traffic.

Limitations of Signal Coordination

As we strive to improve signal progression and coordination within the City of Elmira, it is important that the public understand the limitations of signal coordination. While traffic signal coordination can reduce stops and travel delays along a particular corridor, travel along a particular street may not completely experience non-stop free-flow conditions due to the following conditions:

• Capacity issues as a result of increased traffic caused by growth
• Complexity of the street system.
• Equipment malfunction
• Street construction
• Traffic incident

Drive the speed limit. Signals are timed to work best when traffic goes the speed limit. Driving faster will simply get you to the next signal too early, causing you to stop more often. The best way to avoid stopping is to slow down when you see a red light ahead and give it time to change to green.

Stop behind stop bars at red lights. Many intersections have vehicle detectors (wire loops) embedded in the pavement. These signals can detect the presence of vehicles and let the controller know that vehicles are waiting. Stopping behind the bar ensures that the controller "senses" your car and keeps the crosswalk clear for pedestrians.