The Need
Smart vehicles need smart traffic signals.
Traffic signal controllers have been around almost as long as the vehicle, communicating "Stop" and "Go" to the driver. But our vehicles have become much more advanced in the last couple decades, and the need for a driver is starting to disappear. Connected and automated vehicles could use traffic signal information to improve performance, fuel efficiency, and prepare for the unavoidable stop.
Isn't there already a solution?
Traffic engineers are currently working on devices that will communicate the traffic signal state to the vehicles, but this will take time to deploy and a significant amount of investments. However, we are able to communicate this information now with existing technologies and communications to provide some benefits of connected vehicle technologies.
Doesn't a traffic signal know when it is going to change?
Yes, and no. A traffic signal controller is basically a logic control that responds to if, then, and when. If a traffic signal controller is fixed-time, then the controller will most likely behave the same way, every day. That is an easy thing to predict. It is possible to learn this information through crowdsourcing the data, but when the traffic signal controller is actuated (the control responds to the traffic demand), then the problem becomes much more complicated.
Special cases need special treatment.
Fire trucks, ambulances, police vehicles, heavy rail, light rail, transit vehicles, and even passenger vehicles or pedestrians can cause the traffic signal controller to deviate from the normal plan. The traffic signal must respond to these multiple users, often in a unique manner or sequence, and these events are random. This is why real-time communication to the traffic signal controller is necessary. Other special events, like sporting events, are also random events by duration which contribute to the complexity of predicting the traffic signal controller operation.
Traffic signal controllers have been around almost as long as the vehicle, communicating "Stop" and "Go" to the driver. But our vehicles have become much more advanced in the last couple decades, and the need for a driver is starting to disappear. Connected and automated vehicles could use traffic signal information to improve performance, fuel efficiency, and prepare for the unavoidable stop.
Isn't there already a solution?
Traffic engineers are currently working on devices that will communicate the traffic signal state to the vehicles, but this will take time to deploy and a significant amount of investments. However, we are able to communicate this information now with existing technologies and communications to provide some benefits of connected vehicle technologies.
Doesn't a traffic signal know when it is going to change?
Yes, and no. A traffic signal controller is basically a logic control that responds to if, then, and when. If a traffic signal controller is fixed-time, then the controller will most likely behave the same way, every day. That is an easy thing to predict. It is possible to learn this information through crowdsourcing the data, but when the traffic signal controller is actuated (the control responds to the traffic demand), then the problem becomes much more complicated.
Special cases need special treatment.
Fire trucks, ambulances, police vehicles, heavy rail, light rail, transit vehicles, and even passenger vehicles or pedestrians can cause the traffic signal controller to deviate from the normal plan. The traffic signal must respond to these multiple users, often in a unique manner or sequence, and these events are random. This is why real-time communication to the traffic signal controller is necessary. Other special events, like sporting events, are also random events by duration which contribute to the complexity of predicting the traffic signal controller operation.