Need for traffic optimization
Texas Transportation Institute estimates travel delays of between 17–55 hours of delay per person per year relating to congestion on the streets. Traffic device optimization hence becomes a significant aspect of operations.
Several techniques exist to reduce delay of traffic. Generally the algorithms attempt to reduce delays (user time), stops, exhaust gas emissions, or some other measure of effectiveness. Many optimization software are geared towards pre-timed coordinated systems.
Normally optimization of signals along a road is a challenging and expensive task, because the sources for traffic monitoring have been limited to inductive loops, cameras or manually counting. However, due to recent advances in information technology, portable devices with Bluetooth and Wi-Fi communication are becoming more common,enabling real-time continuous traffic monitoring and adjustments to traffic signal timing.
By placing sensors along roads, tracking Bluetooth and Wi-Fi devices in passing vehicles, the solution is able to accurately detect and record how long it takes a car to drive along a corridor, segment by segment and in total. This provides historic data for traditional timing methods but also enables real-time feedback to changes in signal programs along with the ability to continuously detect traffic levels and travel time to trigger transitions among programs.
Real time traffic control
Several systems are capable of monitoring the traffic arrivals and adjusting timings based on the detected inputs. Traffic Detectors may range from Metal Detectors to Detectors that use Image Detection. Metal detectors are the most popular in use. Image detection devices exhibit numerous problems including degradation during bad weather and lighting.
Traffic actuated signal systems use detectors to adjust timing for:
- Only the main street - semi-actuated system
- Both main and cross streets - fully actuated system.
The above method is primitive real-time signal optimization at best. This method will optimize one traffic signal at a time. However, in the real world, a motorist's commute involves driving through multiple signals. Thus, multiple traffic signals need to be collectively synchronized in order to be effective. One such system that has gained significant popularity in the United States is InSync.
It has been suggested that the benefits of traffic optimization have never been scientifically justified. It inherently favors motorized traffic over alternate modes such as pedestrians, bicyclists, and transit users and may promote more auto use. It is suggested that an alternate approach could involve traffic calming, and a conceptual focus on the movement of people and goods rather than vehicles.
- Michael J. Vandeman, "Is Traffic Signal Synchronization Justifiable?"], April 15, 1994