EDMONTON -- The City of Edmonton is using an app to estimate how much commutes will be affected if the speed limit for residential and collector roads falls from 50 km/h to 40 km/h. 

Council has been asked to consider decreasing the limit for local residential and collector roadways from 50 km/h to 40 km/h. 

Speed limits in neighbourhoods in central Edmonton, deemed the core zone, could be decreased to 30 km/h.

Coun. Aaron Paquette said members in Ward 4 immediately had questions about how the proposed change would affect their schedules. 

"I was going and driving the route out of their neighbourhood to see what the time difference would be at different speeds," he said. "I didn't notice much of a difference and I wanted to be sure my experience was backed by data."

With help from University of Alberta students, the City used its own data and Google Maps technology to develop an app to compare drive times under different speed limit scenarios. 

"I live at the edge of the city and coming in to City Hall every morning, if I'm driving, 0.7 minutes longer of a commute," he found. "So about 40 to 45 seconds."

Jessica Lamarre, the city's acting director of traffic safety, said the tool isn't perfect but does give residents an idea of what could happen if limits change. 

"If you're taking a test drive after a run on the tool, you might find that there's a reason traffic's not flowing as per the norm that day, and it might result in a difference," she explained. 

"But overall, when we're estimating times, we're taking what the average looks like."

City of Edmonton Core Zone Map by CTV News Edmonton on Scribd

Currently, arterial roads in residential areas are not part of the proposal and would not see a decreased speed limit.

City administration is studying the frequency of crashes, area land use, traffic volume, and other speed reductions (like playground zones) to decide which roads should be exempt from lower speed limits.

The traffic safety department says the enhanced safety that would result from lower speeds trumps slightly longer drive times. 

"Speed is a factor in absolutely every collision, both the frequency and the severity. So when we take a look at lowering speeds, we're talking about increasing safety for everybody on the roads."

Speed limits will be debated at the Feb. 27 Community and Public Services Committee meeting before heading to council. 

The proposal has been under consideration since 2018. City administration will present their findings to council this month.