Rumble Strips, Colorado Style

They’re hard to see, but the rumble strips in this photo from Colorado are right on the white line.

In late spring, bike riders in Sussex County encountered rumble strips that a DelDOT contractor erroneously ground in the center of the shoulder along a couple of popular cycling routes. Colorado seems to have figured this issue out, at least along one road up in the mountains.

Even though I’ve been babysitting my grandkids (a baby and a toddler ) and my biking hours have been somewhat limited, over the past several weeks I have still been able to enjoy some riding in Boulder, CO, and some recreational paths (dubbed “rec paths”) in and around Frisco (near Breckenridge).

Just a few days ago, for example, I rode the Swan Mountain 20 mile loop, leaving from Frisco.  Knowing the Delaware issue with rumble strips, I noted what the Colorado DOT did along one stretch of rec path.  In the photo above, the rumble strips (barely noticeable) are coincident with the extra-wide white line separating the motorway from the (2-way!) bike-ped path. Bicyclists are unaffected by the rumble strips, but motorists are alerted if they stray towards the rec path.

In this section of the Swan Mountain loop, the rec path is now on the other side of a divider from the road.

I can’t resist sharing a few other comments and photos from the rest of my Swan Mountain ride. Right after I took the first photo, I started across the Dillon Lake Dam, where the rec path parallels the road (which is above and to the left in the photo). The builders of the dam and the road showed remarkable foresight in providing a path for biking and walking, in addition to one for cars!

The rec path travels through the town of Dillon, separated from the town streets for the most part (one section completed just a couple of years ago) and continues to Keystone.  I turned off to go up and over Swan Mountain.

This 2-year old section of rec path quickly leaves housing communities behind as it climbs up and through scrub meadows filled with beautiful wildflowers of many varieties. So quiet and remote, with no cars or highways to be seen or heard!  The rec path route was extremely well designed to keep a reasonable grade to climb up and to provide wonderful views of the area’s terrain.

Wildflowers make this section of the rec path a delight to the senses.

Reaching the first crest (unfortunately, there was more climbing to come!), I was greeted with a spectacular panoramic view of Lake Dillon (the reservoir supplies much of Denver’s water) and the mountains surrounding it.

25 mph speed limit…for bikes!

I continued down the path, being sure not to exceed the 25 mph speed limit (the sign is for bikes — no cars on this route!), crossed Swan Mountain Rd., and had one more section of uphill on the rec path before reaching the top where the rec path merges with the road. There are clear signs at the top alerting motorists to the presence of bikes, and as the rec path ends, signs indicate that bicyclists can use the full lane. What an adrenaline rush, to speed down the twisting mountain road, in the middle of the lane! At the bottom I connected with the Breckenridge-Frisco rec path and headed back, right before the skies opened up and it started pouring rain!

* For those who are interested in more Colorado specificatons for rumble strips, I found a reference to a 2001 Colorado report (William Outcalt, Bicycle-Friendly Rumble Strips, Colorado Department of Transportaton, Report No. CDOT-DTD-R-2001-4) in a 2007 New Jersey report on rumble strip policies across the US.  Colorado permits the installation of milled, rolled or formed rumble strips on concrete shoulders and only milled strips on asphalt shoulders. The recommended dimensions of milled rumble strips are 15mm to 20mm (6” to 8”) grooved width, 30.5mm (12”) spacing, and 13mm to 19mm (0.5” to 0.75”) depth, a width of 40.6mm (16”) which can be reduced to 30.5mm (12”) for shoulders less than 1.83m (6’) wide. Offset from the edge line is a maximum of 15.2mm (6”).

  Carol Ireland is a bicycle advocate.

RELATED:

• Cyclists Report That Second Try’s the Charm for Rumble Strip Patch

• DelDOT Contractor Makes 2nd Try at Fixing Bad Rumble Strips

• DelDOT Says It Will Fix Improperly Installed Rumble Strips

• DelDOT admits bumpy bands were improperly installed (Cape Gazette)

• Statewide Rumble Strip Installation Contract (DelDOT)

• Rumble Strip Brochure (DelDOT)

• Rumble Strips and Stripes (FHWA)

• DelDOT’s Bicycle-Friendly Rumble Strip Policy (DelDOT)