On Friday, Denver Public Works and BikeDenver showed the city how converting one motor vehicle lane to a protected bike lane on Broadway could improve safety for everyone who uses the street. The temporary, three-day demo was the beginning of a larger bid to give people on bikes a safe north-south route through the city, and make Broadway less of a deadly chasm to cross.

The same day Mayor Michael Hancock and City Councilor Jolon Clark launched the demo, news broke that a road diet on Boulder’s Folsom Street could get the guillotine after a very short demonstration — and a very loud tantrum from opponents who want to re-widen the street and take away protections for people on bikes.

Opponents of the Folsom project believe slight increases in travel time for drivers are unacceptable, but making the street more dangerous for people who choose to bike is okay. The Boulder City Council will send the same message if they vote to dissolve the road diet Tuesday.

Most of Boulder’s residents who care about the project enough to send in comments support it, according to the Daily Camera, which reported that 57 percent told the City Council they favor the street design (out of about 950 comments). Forty percent opposed the redesign.

Initial data show that the redesign added a minute or two, on average, to drivers’ commutes. This is partly because drivers were so prone to exceed the 30 mph speed limit before the road diet. Now, many drivers still speed, according to measurements taken at the intersection with Bluff Street, but not as severely as they used to. It’s still very early into the demo period, but so far the collision rate has dropped, which is what you would expect with less speeding. Meanwhile the number of people biking on Folsom shot up nearly 75 percent.

These are all desired goals of Boulder planners. But despite the safer street, Boulder transportation staffers have recommended turning Folsom back into two motor vehicle lanes in each direction, rather than one in each direction with a center turn lane.

Why? Supposedly because of poor communication before the project began. Oh, and because officials are worried about plowing the bike lane during a snowy winter. The more likely but less official explanation is that the redesign stirred up some angry people, which has made the city’s political leadership uncomfortable. Now, despite the safety benefits of the project, Boulder looks ready to nix it.

Thirty miles south, Mayor Hancock and Clark, whose district includes South Broadway, praised the idea of redesigning Broadway on Friday. The three-day pop-up bike lane was a precursor to a larger, six-week demo next spring. With the situation in Boulder unfolding the same week, it was hard not wonder what Denver’s decision makers would do in the same situation.

Clark said that Denver’s phased process will afford policymakers more room to make Broadway’s transformation a reality.

“Between this demo and the one in April, it won’t be a surprise for people,” Clark said. “We’ll be able to tweak it and play with it and get to the right place. Also, tackling something like Broadway, arguably one of the most dangerous streets… sets the table for next conversation. If we can show that this can work, then where can’t we make it work?”

Clark had an epiphany, he said, when he saw his kids riding on the pop-up bike lane by themselves: “For the first time, Broadway was a safe place to bike.”

Clark sounds dedicated to transforming Broadway into a street made for people, and so did Hancock on Friday.

“We’re very fortunate that Mayor Hancock and Councilman Clark fully endorsed this project,” said BikeDenver Executive Director Molly North. “We need those two as well as the rest of the allies on City Council, even if there are challenges from residents and leadership. Our leadership needs to be bold and stand behind [the project], and maintain that this is the best thing for Denver.”

Bicycle Colorado Executive Director Dan Grunig advocates for bike infrastructure statewide. He said that data on its own doesn’t dictate better streets. “The design of the road is not just a data decision, it’s a political decision, and that’s why there’s advocacy groups like us,” he said. “Data is just one component of the decision. It’s really a broader question about building the political support.”

Cities like Seattle, Chicago, and New York, which have successfully built out significant protected bike lane mileage, all weathered a backlash at some point. No one thinks twice about these streets a few years after the design has changed, but when the transformation is fresh and people are still adjusting to it, elected leaders need a stiff spine to stay the course.

If Denver’s politicians don’t flinch when the going gets a bit rough during the inevitable adjustment period, that’s how we’ll know the city has taken a legitimate step forward.