Vulnerable road users (VRUs) like pedestrians, cyclists and motorcyclists are more difficult to protect because they are hard to see, difficult to track and they often emerge suddenly from unexpected quarters.

And, of course, VRU’s are not equipped with airbags, roll-cages and seat belts. Alerting drivers to nearby vulnerable road users is a possible solution.

European researchers have developed a bespoke system that will prevent accidents by using highly advanced sensing systems which track road users. The WATCH-OVER project uses a cooperative system, where both cars and vulnerable road users “are seen” and able to “communicate” with each other.

How it works

The system has been realised in two versions: one pre-crash version that uses a stereo camera system, and the other a warning system using a mono-camera system combined with communications technologies.

Sensors are effective for pre-crash systems, which usually kick in just seconds before impact. But to track vulnerable road users further away, sensors are not enough; it is essential to back sensors up with other technologies like communications.

 “This is vital because camera-based systems cannot see around corners, for example,” explains Luisa Andreone, coordinator of the WATCH-OVER project.

The strength of the warning system lies in its cooperative nature – drivers and other road users effectively working together. To achieve this, VRUs would need to carry or wear some sort of transmission device that alerts vehicles of their presence.

WATCH-OVER tested the system with positive results, finding that it worked well under most of the cases encountered in urban areas. 

Ultimately, for this system to succeed on the market, it would need to be integrated into existing electronics, like a mobile phone, or into clothing. For the test, WATCH-OVER developed a wearable device, to prove the principle.

Not ready yet

But the warning system is not ready for commercialisation yet.

“You have to remember that this was a scouting project,” says Andreone. “We were pioneering a new area for road safety using communications technologies. We showed that the principle is sound, but more work is needed to make the warning version of the system ready for market.”

Current communications technologies are the main constraint. The chip set used in WATCH-OVER could scan over the distance, but it had limited accuracy calculating angle-of-approach, and it is not part of the standard for Vehicle-2-Vehicle (V2V) communications.

It is important that the system can accurately distinguish between safe and dangerous situations, to avoid “false alarms” caused by inaccurate angle-of-approach calculations.

“You might have a pedestrian walking down the street who has no intention [of] crossing the road. Obviously [in this case] the driver should not receive a warning. It would make the system useless,” notes Andreone.

Costs and complexity

Costs and complexity are important issues for in-car technologies, too. The automotive industry is an intensely competitive market. So future solutions will also have to take this into account.

What’s more, the technology used by vulnerable users must be extremely portable, reliable and should require very little power, suggests Andreone. Here, mobile phone technology could play a key role in implementing WATCH-OVER’s solutions – somehow piggybacking on existing phone technology, or via low-cost new chips and sensors that could be added to phones.

These issues are not fully resolved, according to Andreone. But in the meantime, WATCH-OVER has demonstrated to the industry that better protection for vulnerable road users is within reach.

The WATCH-OVER project received funding from the ICT strand of the Sixth Framework Programme for research.

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