Project: Dark Signals

by Michael Mullaney on December 2, 2009

“Project: Dark Signals” may sound like Lex Luthor’s latest nefarious plot or something hatched by the Dharma Initiative, but it’s actually far more interesting.

You know the scene: An aggressive ice storm or thunderstorm downed power lines and resulted in a blown transformer. With no functioning traffic signals at intersections, your morning commute is littered with near-misses and drivers clearly ignoring the rules of the road. As if things weren’t stressful enough, the occasional fender benders slow traffic down to a snail’s pace. Cringe-worthy stuff.

This is precisely the scenario that Professor Al Wallace and Research Engineer Jeff Wojtowicz are endeavoring to erase. And their weapon of choice is Project: Dark Signals.

Here is how Wallace frames the problem:

During power outages signalized intersections typically lose all functionality. Whether the outage is a few seconds or an extended period of time, safety at the intersection is compromised. Many motorists do not know who has the right of way when approaching a dark signal. Typically, two actions take place: motorists on the ‘main’ road assume they have the right of way and do not stop, or motorists will treat the dark signal as an all way stop. In both cases safety is compromised because motorists have different views on how the intersection should operate. In addition to safety, the efficiency of the intersection can quickly degrade. Current practices of operating these intersections are somewhat primitive, ranging from ‘do nothing’ to installing portable generators.

The project is laid out in Wallace and Wojtowicz’s comprehensive report for the New York State Department of Transportation. There’s no way to absolutely prevent blackouts and power outages, so the state needs to take precautionary measures, the report says. Project: Dark signals calls for the deployment of backup battery systems at all intersections. (Only a few such systems have been installed across the state.) Wallace and Wojtowicz mention solar, fuel cells, and all sorts of interesting power options. Since conventional incandescent light bulbs take more power to run, the report says the state should start phasing in more efficient, energy-sipping LEDs in traffic signals – which generally use about 85 percent less electricity to run.

The state should compile intersection data including traffic volume, injury accidents, nearby schools and children, and average speed toward the creation of a robust schedule that prioritizes the deployment of these new traffic signal backup systems, according the plan. While Project: Dark Signals is still being formalized and reviewed, Wallace and Wojtowicz recommend that New York State quickly launch an educational program to re-familiarize drivers with the proper procedures for dealing with dark traffic signals, to help boost near-term safety and curb the number of accidents. A PDF of the full 105-page Project: Dark Signals report can be found here.

In general, Wallace likes to keep traffic moving. From a traffic engineering and decision sciences perspective, you want cars moving from Point A to Point B at stead speed, with as little accelerating or breaking as possible. The best way to do this, Wallace says, is to make the roads safer for drivers:

“It’s clear that safety and efficiency go hand-in-hand,” Wallace said. “We want to keep drivers moving at a constant speed. Acceleration and deceleration are where you use the most energy, and where you’re the least efficient. Accidents, which are already horrible for the people involved, also affect the rest of us by causing congestion, making us late, and ultimately wasting a lot of energy.”

Read more about Wallace’s traffic research here, and check out this story (and this one too) about his emergency logistics and supply chain research.