At present, traffic controllers are interfaced to the signals and sensors at a traffic intersection through a single wire for each sensor or indicator that is either ON or OFF. Some signals combine several indicators (like traffic signals) and require multiple wires to operate. Often innovative device types are not directly supported by the traffic controller and cannot be used optimally by the traffic intersection. For example, the pedestrian crosswalk timer learns its timing from the previous state of the intersection and it never synchronizes with the traffic controller.

     Dr. Richard Wall and Andrew Huska of the University of Idaho started researching the feasibility of implementing the IEEE1451 Plug and Play (PnP) communication standard for traffic signal and sensor communication. The LiteBright project is part of this larger research program. The objective of the LiteBright project is to build a prototype network as a proof of concept for Plug and Play traffic signal communication. This project is funded by the National Institute for Advance Transportation Technology (NIATT).

     This project focuses on the pedestrian signals and sensors. The new PnP compliant pedestrian signals will always know how much time is left for crossing the intersection and will always give the correct information to the pedestrian. The new PnP network will also allow for new innovative devices to easily be implemented into a traffic control system. Figure 1, shows how the new network can be implemented along side the current system.

     The current traffic control cabinets are crowded with many wires. The field engineers must understand the complex wiring diagrams in order to correctly connect new signals or sensors to the intersection. Some indicators, like pedestrian countdown indicators, are not supported directly by the traffic controller. These devices monitor other devices which are connected to the controller, like the Walk/Don’t Walk indicators, in order to determine the correct functioning state. The pedestrian countdown indicators monitor the Walk/Don’t Walk indicators in order to calculate how much time remains for safe crossing of the intersection. When the intersection timing changes (this can happen for many reasons, including emergency vehicles and peak vs. off-peak time of day) the countdown indicators take time to “learn” the new pattern. Until it can synchronize with the new pattern, it will display incorrect times and could possibly leave a person stranded in the middle of the intersection.