The vehicle-to-infrastructure (V2I) technology connects to traffic-signal networks in eight cities to indicate the “time-to-green.”
By Murray Slovick, Contributing Editor
Ever sit in your car at a stoplight wondering if it will ever turn green? We all have. But if you happen to be in one of the 2017 or 2018 model year Audis equipped with Traffic Light Information (TLI), and you happen to be in Washington D.C. (or seven other cities), your car will let you know how long until the light turns green when approaching one of those city’s connected traffic lights.
The system uses a wireless connection (via the on-board 4G LTE data link) to receive real-time signal information from city-wide traffic-management systems. When the light is red, the time remaining until the signal changes to green will be displayed in the instrument cluster in front of the driver or in the head-up display (if the car is so equipped). The countdown increases safety by giving an exact amount of time until the signal will change.
Audi America announced that more than 600 intersections in the District of Columbia now support the “time-to-green” feature.
TLI doesn’t use cameras to determine when the light is going to change. Local data sources provide information about traffic-light patterns, and the in-car system uses that data and the motion of the car to predict exactly how long it will be until the green light turns red. TLI, initially launched by Audi in collaboration with Traffic Technology Services (TTS) in Las Vegas, Nevada, is now offered in six other cities: Palo Alto and Arcadia, Calif.; Dallas and Houston, Texas; Portland, Ore.; and Denver, Colo. With the addition of Washington, more than 1,600 intersections across the U.S. support TLI.
According to Audi, future iterations of V2I technology could include integration with the vehicle’s start/stop function, firing up the engine a few seconds before the light turns green. Other advantages provided by “time to green” systems include optimized navigation and the use of Green Light Optimized Speed Advisory (GLOSA) routing.
GLOSA communicates with infrastructure to figure out the speed needed to hit as many consecutive green lights as possible, reducing stop times and unnecessary acceleration in urban traffic situations. Decreasing red-light stops helps increase gas mileage by reducing the acceleration required to leave a stop light. It also cuts down on emissions.
As V2I systems mature, they could tell a car when a light will turn red, allowing an autonomous vehicle to ease off on the throttle if it knows it won’t make the light, improving fuel economy and reducing congestion on crowded roadways.