Virtual replacement for traffic lights given green light for pilot tests

Researchers suggest your commute could be cut by up to 20 percent using the new system.
Written by Charlie Osborne, Contributing Writer

In what is potentially a world-first, researchers have launched a pilot program which replaces physical traffic light systems with virtual alternatives.

Traffic light systems often play a crucial role in traffic flow. When road systems are organized effectively, they can provide a way to increase the efficiency of travel. However, in poorly-managed setups, traffic lights may leave drivers cursing at the wheel behind a red light on a deserted road or may also cause huge traffic jams.

Love or hate them, for many road systems worldwide, they are necessary -- but this does not mean they cannot be improved.

The challenge of improving road traffic flows and the effectiveness of traffic control methods is at the heart of a new research project led by engineer Rusheng Zhang, together with a team from Carnegie Mellon University in Pittsburgh.

As reported by MIT Technology Review, the researchers developed an alternative called Virtual Traffic Lights (VTL).

The infrastructure-free traffic control scheme relies on vehicle-to-vehicle (V2V) communications, a core component of modern cars and the development of autonomous vehicles.

V2V is able to share GPS data, maps, speed, and the intended direction of moving cars.

According to a paper describing the system (.PDF), Dedicated Short Range Communications (DSRC) technology can be used in conjunction with V2V to coordinate traffic at intersections without the need for physical traffic lights.

V2V communication provides data from vehicles, which is then used by the DSRC-based VTL to coordinate moving traffic.

A pilot program has been launched in Pittsburgh. Two vehicles were set up to approach a junction, one of which acted as the "lead" car.

The leader was given a virtual red light display, which left the following vehicle with a green light. The leader was then issued a green light and permission to move. Once this car moved on, the "leader" status was then passed to the next vehicle.


Objects such as houses and trees were between the transmitters and receivers used by VTL and in the pilot area, which helped the engineers test the system in real-world scenarios.

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After testing this system over 20 junctions in addition to the presence of four-way stop signs, the researchers say that VTL is able to reduce traffic congestion, carbon emissions, and the average commute time by up to 20 percent.

However, there is the potential to increase efficiency by up to 30 percent.

In addition to shaving off commute times, the team also suggests that virtual traffic lights could be safer, too, as many complicated junctions are not currently policed due to the expense incurred when traffic light systems are installed.

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"Our results show that VTL technology can sense the ensuing conflict between vehicles at perpendicular lanes 250 feet away from the intersection, on a regular basis, at 100 ms intervals," the researchers say. "This provides experimental evidence on how VTL technology can manage traffic at an intersection via V2V communications using DSRC radios."

There are challenges ahead, such as at more complicated or unstructured road crossings and when pedestrians are involved. However, the research does show that V2V technology may not only transform our vehicles but also our road systems in the future.

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