Editor’s note: An earlier version of this story misquoted Boulder Transportation Planner Ryan Noles. He said, “The value in studying the effects of lowering the speed from 25 mph to 20 on specific streets is we can see the characteristics of those streets. There are varying street widths and different contexts throughout the city of Boulder. Some streets are wider, some are more parked up, some have higher residential densities. From an engineering perspective it would be useful to know where exactly those things contribute to slower vehicular speeds.”
After more than a year of spreading the mantra “20 is plenty,” some Boulder activists got what they wanted from City Council on Tuesday: slower local speed limits.
Officials are set to come back to Council with an ordinance to be formally adopted this year to change the top legal travel velocity on residential roads from 25 mph to 20, with sign replacement set to be completed in summertime. Where signs are not posted, the default speed limit will also be lowered to 20.
“We’re psyched about that. We’re hoping the broader community gets behind it,” Boulder Transportation Advisory Board member Mark McIntyre said.
City staff had recommended a less direct and more expensive approach than Council ultimately took. While Council decided to go ahead and begin changing the speed limit signage across the entire city at a cost of $65,000 this year, staffers had suggested piloting the lower speed limits on certain roads performing a community survey, crash data review and a technical report at a cost of $102,500, with the chance to implement the lower speeds across the rest of the city later for another $60,000 if the results suggested that course of action.
Speed limits themselves, without changes to how streets are designed, including their width and presence of mitigating infrastructure like speed bumps, may not be enough to change driving habits. But the reduction could set the city up to implement slowing physical adjustments over time.
“We have a lot of experience trying to change people’s behavior just with speed limits in our community, we have never been successful doing that,” Interim Transportation Director Bill Cowern said. “… You will have set a different expectation, especially a different expectation in the community, in the neighborhood, and they will come to the city and say ‘we want speed mitigation on our street.’ And over time you will put that speed mitigation out there. It isn’t going to come from posting speed limit signs.”
The Transportation Advisory Board unanimously recommended Council skip the pilot and study suggested by staff, and move to change the signage and policy right away.
“I think that city staff are assuming the goal of 20 is plenty, changing the speed limit, is to slow drivers down on residential streets. I think we agree that is a goal,” board member Tila Duhaime said. “I think what staff’s approach is assuming is that this change needs to demonstrate it will advance that goal all by itself. We are saying it’s part of a package of things that need to happen sort of all at once to get people to slow the heck down everywhere.”
Mayor Sam Weaver noted analysis of any potential safety gained by lowering speed limits alone could still be done based on findings gathered from changes to residential roads across the entire city, just as it could based on the staff-proposed pilot, since crash data is consistently collected across all of Boulder.
“The value in studying the effects of lowering the speed from 25 mph to 20 on specific streets is we can see the characteristics of those streets. There are varying street widths and different contexts throughout the city of Boulder,” city Transportation Planner Ryan Noles said. “Some streets are wider, some are more parked up, some have higher residential densities. From an engineering perspective it would be useful to know where exactly those things contribute to slower vehicular speeds.”
An official Council vote on the new speed limit law should take place next month.