Boulder Canyon Drive/CO 119 is undergoing construction to repair 2013 flood damage. The improvement project will also resurface and widen the road. As part of this project, the Boulder Canyon Trail will be extended to Chapman Drive with two additional bike underpasses. There will be road delays during construction with one-way traffic stoplights. The project began in March 2019 and is expected to be completed by summer 2020.

When crews are blasting rock, both Boulder Canyon Drive and the Boulder Canyon Trail will be closed. Typically, these closures will happen 2 days a week during two 2 hour shifts. Chapman Drive will not be accessible from Boulder Canyon. Because Fourmile Canyon is still closed to recreational bike traffic 8:00-4:30 M-F, both the main Betasso trailhead and the Fourmile trailhead will not be accessible by bike.

Update: 7/5/2019 – Starting Wednesday, July 3, cyclists will be allowed to travel in both directions on CO119 west of Fourmile Canyon Road. Project crews will be updating signage in the coming days.

  • Between Fourmile Canyon Road and Arapahoe Avenue, all westbound cycling is restricted and eastbound travel is restricted between the hours of 9:45 a.m. and 2 p.m. Monday through Thursday. In this area all westbound cyclists and eastbound cyclists traveling between the hours of 9:45 a.m. and 2 p.m. on these days must use the Boulder Canyon Trail at all times. This is a safety measure to help keep the public safe in the busiest work area.
  • The Boulder Canyon Trail, from the canyon mouth in Boulder to the Fourmile Canyon trailhead, will be closed, Monday – Thursday, 7 a.m. to 2 p.m.  Due to the path’s proximity to the blast area, this is a safety measure to make sure no pedestrians or cyclists are inside the blast zone during the day.
  • If cyclists ride on Chapman Drive to CO119, they can now travel eastbound or westbound. Please note that anyone traveling eastbound on CO119 between 9:45 a.m. and 2 p.m. Monday through Thursday will be turned around at Fourmile Canyon Road. Additionally, the signalized closure for the barrier replacement work that’s occurring just east of Chapman Road is long and steep. This area could be difficult for less experienced cyclists. Cycling access remains open but is not advised in this area.
  • There are no closures on the Betasso Canyon Link Trail. Cyclists can access this area from CO119, however, riders traveling from Boulder Monday through Thursday must be west of Fourmile Canyon Road by 6:45 a.m. to avoid the closure between Fourmile and Arapahoe Avenue.
  • Boulder County is currently making improvements along Fourmile Canyon. At this time, all non-residential cycling is closed through the canyon. Please contact Boulder County for more information.

You can subscribe to text alerts about the canyon closures by texting CO119 to 21000 or learn more information about the project and see this week’s closures.

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