Page 8 - May-June 2023 Vol 41 No 1

NORTH CAROLINA STATE By Lisa Hood Skinner
Researchers Propose Fourth Signal

Color for Autonomous Vehicles

Future traffic lights may contain of civil, construction and environmental
significant new messages for autonomous engineering at NC State, says the white
vehicles (AVs). Yes, the color red will still phase concept rests on the fact that it
mean stop. Green will still mean go. And is possible for AVs to communicate
yellow should still signify slow/prepare to wirelessly with each other and the
stop. computer controlling the traffic signal.
But a new “white phase light” that could He said when enough AVs are
be added would have two functions: it approaching the intersection, this would
will tap into the computing power of AVs activate the white light. The white light is
that communicate wirelessly with each a signal that AVs are coordinating their
other AND the computer that controls the movement to guide traffic through the
traffic signal. intersection more efficiently.
For the humans driving non-AVs, Any non-automated vehicles (those
the white phase light simply would
indicate they should follow the car in
front of them. Some North Carolina
State University researchers say their
computational simulations show the new
approach significantly improves travel
time through intersections and reduces
fuel consumption.
A Fourth Signal “White Light” Proposed
The transportation researchers are
proposing that fourth signal “white
light” for a myriad of reasons, including
enabling autonomous vehicles to help
control traffic flow while letting human
drivers know what’s going on.
Ali Hajbabaie, corresponding author
of the paper and an associate professor

8 TPW May/June 2023