During the week of August 16, Jefferson County’s contractor, B. Jackson Construction, will grind approximately 19 miles of centerline rumble strips on several mountain arterial roads. The road segments will be as follows:

1. Brook Forest Rd (CR 73 / Blue Creek Rd) - 2.6 mile
2. Brook Forest Rd (Brook Forest Dr / Forest Estates Rd) - 0.3 mile
3. CR 73 (Wonderview Ave / Marshmerry Ln) - 1.3 mile
4. CR 73 (CR 64 / US285) - 5.0 mile
5. Shadow Mtn Rd (CR 73 / Shadow Mtn Dr) - 3.4 mile
6. Lookout Mtn Rd (Golden city limits / SH 40) - 6.5 mile
7. Golden Gate Canyon Rd – 1,145 LF at recent rock scaling project, 0.5 miles west of Jefferson County Central Shop

Work will not start until after 8:00 a.m. to accommodate morning commuters. The entire grinding work is expected to be finished by the end of the week. County crews will then stripe the yellow centerline later this summer.

Workers will grind the areas and remove asphalt millings at the same time. Drivers should expect delays of only a few minutes as traffic flaggers route vehicles around the moving operations in controlled waves. Asphalt millings from the grinding operations will be re-used by the county for other road maintenance projects.

Rumble strips are grooves in asphalt pavement that are milled-in perpendicular to the direction of travel to alert drivers. As a vehicle passes over the rumble strips, noise and vibration are produced, alerting the driver they are approaching a hazard.

There are two main types of rumble strips:

• Shoulder Rumble Strips: placed at the outermost edge of the paved surface to warn motorists their vehicle is entering a part of the roadway not intended for routine traffic use, and
• Centerline Rumble Strips: placed on the centerline of undivided highways to warn drivers they are leaving their intended lane of travel. Centerline rumble strips have been demonstrated to reduce head-on and opposing direction sideswipe crashes. In addition, drivers tend to slow down when approaching curves of winding mountain roads.

The public reaction to the County’s centerline rumble strip program has been mostly positive. Several drivers have recounted their experiences of drifting over the centerline at night or in snowy conditions and being alerted by the noise. In other cases, bicyclists riding along the shoulder of the road appreciate the centerline rumble strips because they hear vehicles approaching from behind them.

This will mark the 3rd centerline rumble strip grinding project funded by Jefferson County since 2005. There will now be approximately 60 miles of centerline rumble strips on County’s mountain roads.

For more information, please contact Dixie Shear in the Transportation and Engineering Division, at (303)271-8495, or dshear@jeffco.us.