Imagine you’re driving toward a busy intersection. A car approaching from the front is about to apply the brakes, but you have no way of knowing. By the time you realize it’s stopping, it’s too late, and a crash happens. Each year, numerous such collisions occur, but a simple change in our vehicles could dramatically reduce their number.

This simple idea is putting brake lights on the front of vehicles. This could be a game-changer in road safety. A recent study from Graz University of Technology in Austria suggests that these front-facing brake lights (FBLs) could help avoid up to 17% of intersection collisions and lessen injury severity in as many as 25% of cases.

It’s a low-cost, easy-to-implement solution with the potential to save thousands of lives, yet no car on the road today has it. So why haven’t we added this obvious safety feature before? Well, until now, the idea lacked strong real-world evidence. That’s exactly what the new study provides, by recreating real crashes, testing the idea in simulations, and determining just how helpful a front-facing brake light can be.

“The aim of this study is therefore a prospective evaluation of the safety performance of an FBL by means of a counterfactual simulation on the basis of real traffic accidents at junctions,” the study authors note.

Testing the power of FBLs

The researchers began by examining 200 actual vehicle accidents that took place at intersections in Austria. They used data from the Central Database for In-Depth Accident Study (CEDATU), which records detailed information about how crashes happen. 

Using this data, the team reconstructed each crash. Basically, they created a timeline of events showing how the vehicles moved, when the drivers braked, and how the collision occurred. Next, they ran computer simulations of each crash scenario, but this time, they added a twist: they assumed that the cars approaching from secondary roads had green front-facing brake lights. 

These lights would signal to other drivers, especially those coming from the side or in front, that a vehicle was slowing down. In the simulations, whenever these lights were visible, drivers were assumed to react more quickly. The researchers tested three possible reaction times: 0.5, 1.0, and 1.5 seconds. The faster the reaction, the better the outcome.

The results were surprising. Depending on the assumed reaction time, the simulations showed that 7.5% to 17% of the original accidents could have been completely avoided with front brake lights. In up to 25.5% of cases, the lights wouldn’t stop the crash entirely, but they would reduce the speed of impact, enough to lower the severity of injuries. 

In one example, the average crash speed in minor-injury cases dropped from 44.8 km/h to 28.8 km/h when the driver reacted half a second faster. This drop can mean the difference between a few bruises and a life-threatening injury.

“FBL is a promising driver assistance system. According to the European Commission, almost 18% (3,690) of road users were killed at junctions. With the safety performance of an FBL, up to 220 car-to-car accidents are potentially preventable, and 650 are positively influenceable; i.e., the consequences of a collision could be mitigated,” the study authors said.

Green lights at the front and side would do the job

The study also revealed some key challenges. In about a third of the accident cases, the front brake lights wouldn’t have helped, not because they weren’t useful, but because they weren’t visible. The angle of the vehicles meant that even if the lights had been there, other drivers couldn’t see them. 

To fix this, the researchers suggest adding brake lights to the sides of vehicles as well. Their simulations show that something as simple as adding a green brake light to the front and perhaps the sides of a vehicle could make a big difference in road safety. 

These lights are easy to install, cheap to retrofit, and require no complex new technology. Unlike many safety upgrades that rely on expensive sensors or automation, this is a visual signal that humans can instantly understand.

However, there are limits. The effectiveness of FBLs depends entirely on whether other drivers can see them in time. That’s why the team recommends more real-world testing, including wider field trials. 

One such test has already taken place in Slovakia, but more data is needed to convince car manufacturers and policymakers to adopt the idea on a larger scale. This is why the study authors plan to continue their research. Hopefully, these efforts will result in a practical FBL design that will end up saving a lot of lives.

The study is published in the journal Vehicles.