Driverless cars: How Scottish scientists can help cyclists avoid crashes with autonomous vehicles

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Scottish researchers have been donning gaming headsets, pedalling around Glasgow, creating light displays and dressing up in odd costumes – all in the name of science.

The activities are just part of a day’s work at the University of Glasgow’s School of Computing Science, where academics have been investigating ways to improve safety for cyclists sharing roads with the self-driving cars of the future.

Their experiments focused on external human-machine interfaces – known as eHMIs – devices that use screens or lights to display information and can be added to surfaces like car doors or roofs to communicate with anyone nearby. The team wanted to test whether the tech could be used to quickly and reliably signal the ‘intentions’ of driverless cars to bike riders, helping to avoid accidents.

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The project has built on several years of research, bringing together human-computer interaction specialists and psychologists. Researchers began with a study to better understand the complex verbal and non-verbal communication between cyclists and human drivers, which helps determine who has the right of way in traffic and at junctions.

Then they worked with cyclists to design several prototype eHMIs that could be fitted on a vehicle body.

They tested three designs, first in a virtual reality environment and then in the real world – on a disused road at the university’s Garscube campus, with a ‘hidden’ human driver disguised as a car seat to better mimic a true autonomous vehicle.

Researchers have been conducting virtual-reality and real-life tests to assess the best way of communicating to cyclists the intentions of self-driving vehicles

One design used a digital screen on top of the car to flash emojis, with a happy face to communicate yielding and a grumpy face indicating the opposite. A second design projected colours onto the road around the car, with green to show it would give way and red to confirm it would not.

Finally, a ring of lights around the car’s exterior used bunching and spreading sequences to signal braking and acceleration.

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The findings suggest a ring of pulsing coloured lights displayed on all sides of a self-driving vehicle could be most effective in communicating how it will move next. And any display was considerably better than none for cyclist confidence and safety, the team found.

Autonomous cars are likely to become commonplace on public roads in the future, so experts are keen to ensure suitable safety features are developed -- a team at the University of Glasgow has been experimenting with ways of signalling to cyclists what a driverless vehicle is going to do next

Study leader Ammar Al-Taie said: “The VR portion of the study helped us to effectively test cyclists’ reactions to the three prototypes in an entirely safe and controlled environment. The results clearly showed that cyclists prefer visual signals which can be understood at a glance. They felt that the emojis were too complicated to ‘read’ without taking their eyes off the road for longer than was comfortable.

“Once we had that feedback, we incorporated the recommendations into improved versions of the three interfaces and set out to test them in the real world.”

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Professor Stephen Brewster, who leads the institution’s Multimodal Interaction Group, said: “It’s clear that keeping it simple is the key to effective communication. Bike riders want to be able to stay focused on the road, so lights placed all around the car help them to make immediate decisions about their next move.

“This feedback will help us refine future designs, which we hope will be of use to manufacturers to consider integrating into the next generations of self-driving cars.”