The application utilizes SPaT data to provide driver recommendations that encourage “green” approaches to signalized intersections. SPaT provides data that are broadcast from road side equipment (connected to traffic signal controllers) to vehicles (I2V communications). The information consists of an intersection map, phase and timing (10 Hz), and localized GPS corrections and the data can be broadcast locally via Dedicated Short Range Communication (DSRC) and/or cellular communications. Example Scenarios include:

• Cruise through green light – do not speed up or slow down. This is the best scenario for fuel economy.
• Coast to stop – slow down earlier to stop at a red light. Energy savings is due to slowing down sooner.
• Modestly speed up to make it (safely) through the intersection on green. Energy savings is due to not having to stop and idle.
• Coast (no stop) – slow down earlier to approach the intersection on the green light. Energy savings is due to not having to idle.

A simulation model was performed on 27 intersections of the El Camino Real Corridor in Northern California. Objectives of the modeling included conducting detailed simulation modeling and testing benefits under different traffic conditions, network conditions, technology penetration rates, and other variables.

FINDINGS

• Coordinated signal control by itself results in approximately 8 percent fuel/emissions reduction over uncoordinated.
• Eco-approach and departure technology provides an additional 4 -5 percent improvement on top of a coordinated corridor.
• In general, 5-10 percent fuel savings can be achieved with 100 percent penetration rate of technology.
• A Smaller penetration rate of technology still has a positive network effect (non-equipped vehicles also have a slight benefit).
• Eco-approach and departure is less effective with increased congestion.
• Application benefits are not very sensitive to communications delay. General Eco-Approach and Departure Application could be accomplished without DSRC, instead using a cellular communications network.