Research at Waterloo Engineering shows on-road bike lanes virtually eliminate unsafe passing by motorists.

Research at Waterloo Engineering shows on-road bike lanes virtually eliminate unsafe passing.

Researchers at the Waterloo Engineering are developing a tool to help urban planners prioritize the installation of bikes lanes after determining they dramatically improve safety.

Their work with predictive computer models builds on a field study that showed on-road bike lanes virtually eliminate motorists getting too close to cyclists when passing them.

Data was collected with sensors and a handlebar camera as researchers cycled hundreds of kilometres on two-lane and four-lane arterial roads both with and without designated bike lanes.

Bruce Hellinga

Waterloo professor Bruce Hellinga.

On two-lane roads without bike lanes, motorists got within a metre of cyclists when passing 12 per cent of the time. On two-lane roads with bike lanes, that number dropped to just .2 per cent.

“Drivers aren’t trying to scare cyclists or be inconsiderate,” says Bruce Hellinga, a civil and environmental engineering professor at Waterloo. “In many cases, they just don’t feel they can leave more space because of the geometry of the road and the proximity of other vehicles.”

On four-lane roads, unsafe passing dropped from almost six per cent with no bike lanes to .5 per cent with bikes lanes.

One metre of separation was used to distinguish safe passing from unsafe passing because it is a legal requirement in some jurisdictions in North America.

The research was motivated by Hellinga’s own experiences cycling to work on busy University Avenue.

“I got frustrated by what I perceived as vehicles getting too close to me,” he says. “You feel very vulnerable when a vehicle comes within what feels like mere centimetres.”

The data is now being used to develop software that predicts the number of unsafe passes on a given stretch of road based on factors including traffic volume and traffic flow.

The goal is a transferable tool to help planners decide where bike lanes and other infrastructure for cyclists would be most beneficial.

Bike lanes not just about ‘giving something to cyclists’

In addition to improving safety, Hellinga says bike lanes make cyclists more comfortable and therefore more likely to cycle, an activity with both health and environmental benefits, while helping put drivers at ease as well.

“It’s not about giving something to cyclists and taking something away from motorists,” he says. “It’s about putting in infrastructure to reduce stress levels and improve safety for both.”

Hellinga collaborated with graduate student Kushal Mehta and former postdoctoral fellow Babak Mehran.

Their paper on a predictive model, A methodology to estimate the number of unsafe vehicle-cyclist passing events on urban arterials, appears in the journal Accident Analysis and Prevention.