Study reveals driver aid that can prevent traffic jams

Adaptive cruise control can help reduce congestion. Photo / Nick Reed

Do you brake too often? If so, you could be one of the leading causes of traffic jams.

However, an active driver aid that's becoming increasingly common in new cars could help lighten your lead foot and reduce logjams on busy roads.

Researchers from Vanderbilt University in the United States demonstrated how one vehicle can cause a chain reaction that affects hundreds of motorists.

Unnecessary braking was found to be the culprit for "phantom traffic jams", causing a wave of braking that gets harder as it goes further down the line until the end vehicles come to a complete stop.

But adaptive cruise control (ACC) has been found to reduce significantly the impact of unnecessary braking.

ACC allows drivers to select a speed the car will maintain without the need for their further input. The technology also reads the speed of the traffic ahead, slowing to maintain a safe distance from the car in front, then returning to the input speed when it is safe to do so.

The university test simulated three lanes of flowing traffic on a Ford closed test track.

The lead cars randomly braked from 100km/h to 64km/h to mimic a traffic disturbance. Several runs were completed with the drivers braking as they saw the cars ahead doing so and again with ACC activated.

The finding: if just one vehicle in three uses ACC, the phantom traffic congestion is reduced. The ACC-enabled vehicles outperformed the humans at the wheel in all braking conditions.

In one of the ACC test runs, the lanes of traffic slowed by a mere 8km/h — but when human reaction was employed, the flow came to a standstill.

Paired with autonomous emergency braking, the adaptive cruise control can end common low-speed bingles by reading the road ahead and adjusting to prevailing traffic flow.

"For years, traffic researchers and engineers have been looking to smart vehicle technologies to reduce traffic congestion, whether that's vehicles that talk to each other or vehicles that can predict the road ahead," says Vanderbilt University civil engineering professor Daniel Work.

"This demonstration was a unique opportunity to understand how commercially available active driver assist technologies can be used to positively influence traffic flow."