Boulder County owns and maintains 18 traffic signals and 7 school zone flashing signs that are placed throughout unincorporated Boulder County. The county typically hires a professional traffic engineering firm to test, set and maintain the signals’ timing and operation.

Boulder county traffic signal at 63rd and Jay Road
County-Operated Traffic Signals are located at the intersections of:
- South Boulder Road and North 76th Street
- South Boulder Road and Cherryvale Road
- Baseline Road and North 76th Street
- Baseline Road and North 75th Street
- Baseline Road and Platt Middle School (near Cherryvale Road)
- North 75th Street and Jay Road
- North 75th Street and Valmont Road
- Jay Road and North 63rd Street
- Jay Road and Spine Road
- Jay Road and North 47th Street
- North 63rd Street and Twin Lakes Road
- Lookout Road and North 95th Street
- Niwot Road and North 95th Street
- Niwot Road and Niwot High School in Niwot
- Niwot Road and Walker Avenue
- Valmont Road and North 61st Street
- Valmont Road and Butte Mill Road
- North 75th Street and Hygiene Elementary School in Hygiene
Traffic lights not on this list are either owned and operated by a municipal government or by the Colorado Department of Transportation (CDOT).