Boulder nears completion of city’s first ‘protected intersection,’ transforming a once-hazardous junction

Update: Boulder’s first fully protected intersection at 30th Street and Colorado Avenue is now complete. A ribbon-cutting will be held on Oct. 3, 2023.

For the past two years, construction has turned the busy intersection at Colorado Avenue and 30th Street into a chaotic jumble of traffic cones, barriers and reroutes. As a result, the city has advised cyclists and pedestrians to avoid it, presumably for their safety. Bike lanes and sidewalks have been closed. 

But this summer, that same street crossing is poised to become one of the city’s safest. When construction ceases, it will mark the completion of Boulder’s first “protected intersection.” 

The $16 million project, which broke ground in early 2021, includes two new underpasses on the south and east sides of the intersection. This will allow cyclists and pedestrians to avoid using the crosswalk, where they are most likely to be hit by a driver. 

Above ground, construction crews are building raised islands on each corner of the intersection. These islands have been designed to create a tighter turning radius for drivers, slowing them down and making them more visible to cyclists and pedestrians inside the intersection. The islands also shorten the distance for people crossing the street, moving them out of the intersection faster and reducing their risk of a collision. 

Such infrastructure is uncommon in the U.S., where cities historically have painted bike lanes on roads or installed signage telling drivers to share the road. The criticism over the recent North Broadway reconstruction project highlights how a bike lane designed about a decade ago with safety in mind no longer meets modern expectations of cyclists and transportation advocates. 

Moreover, a couple of blocks west of the construction site — at the intersection of 28th Street and Colorado Avenue — are right-turn “slip lanes” that cut through the inside corner of an intersection. Such infrastructure is designed to move cars along faster, but they make intersections less safe for cyclists and pedestrians, according to the city’s latest Vision Zero Action Plan. 

The 30th Street intersection is designed to slow cars down and prioritize people who get around by foot, bike, scooter or other means. While less common in U.S. cities, protected intersections are popular in places like the Netherlands and Denmark. 

“I think it’s very much the future of how intersections are going to be designed across the U.S.,” Dave Kemp, a senior transportation planner who left the City of Boulder in January, told Boulder Reporting Lab in a recent interview. “It’d be nice for us to learn from it and have this in our tool box as a way in which we can continue to improve safety for people traveling in Boulder.” 

The 30th Street intersection project falls within the city’s “core arterial network,” a map of busy roads where a disproportionate number of crashes occur. Since 2017, the earliest city crash data available, 325 crashes on the city’s streets resulted in an “incapacitating” injury or death. Cyclists and pedestrians were involved in about half those collisions. The most common location for the crashes was at an intersection. 

Since 2017, four crashes resulting in incapacitating injury have been reported near 30th and Colorado, according to city data. Three involved a cyclist or pedestrian. 

The city is also seeking a federal grant to help build out a separated bike lane along 30th Street, essentially from Baseline to Arapahoe. Similar to the intersection at Colorado Avenue, the 30th Street corridor is frequently traveled by CU Boulder students commuting between the university’s campuses or getting to the Boulder Creek multi-use path. 

The Denver Regional Council of Governments (DRCOG), a regional planning agency governed by local elected officials, is reviewing the city’s grant application for projects along 30th Street. A decision is expected later this summer. 

The city had planned to complete construction on the 30th and Colorado intersection by late 2022. Aisha Ozaslan, a city spokeswoman, said the intersection should be completed by the end of July and the underpass should be completed by the end of the summer.