Sir Francis Drake Boulevard High Friction Surface Treatment

Location

Sir Francis Drake Boulevard near Whites Hill, just west of the Town of Fairfax

City or County Responsible for Project

County of Marin

Author

Julian Kaelon

Organization

Marin County Department of Public Works

Address

3501 Civic Center Drive, San Rafael, CA 94903

Phone

4154734070

Project Description

During the Summer of 2019, the Marin County Department of Public Works (DPW) completed a High Friction Surface Treatment (HFST) project on a one-mile long, hillside stretch of Sir Francis Drake Boulevard. The road is a major arterial in Marin with over 10,000 cars driving it per day. DPW identified the project following a 2014 safety assessment based upon a review of California Highway Patrol collision reports and related coordination with CHP, the County of Marin Sheriff Department and County Fire Department. The safety assessment in 2014 helped guide the project design. Research showed that between 2008 and 2013, a total of 52 collisions have occurred on this one-mile section of roadway, which has several sharp curves. The shoulder on the downhill side varied from a narrow 2 to 4 foot shoulder to no shoulder towards the bottom of the hill. Bicyclists share the downhill travel lane, and 9 (17%) of the identified collisions involved bicycles. The recently completed project entailed resurfacing the full-width of the roadway and applying the HFST to the eastbound downhill lane and shoulder. HFST increases the friction of the roadway in wet weather conditions, thereby reducing the risk of tire slippage for vehicles and bicycles. The Federal Highway Association has HFST as a highly cost-effective road safety measure. It should be noted that other counties in California, such as King County, have used HFST to reduce collision rates. In the case of King County, they subsequently have achieved a Collision Reduction Factor of 76%. Marin County hopes that the recent project will show similar returns as we monitor it moving forward. Further safety improvements were made to the mile-long stretch of Sir Francis Drake Boulevard as part of the project. These included localized pavement repairs (such as elimination of seams and ruts), updated bicycle safety grates, structurally engineered paving mats, updated traffic striping, road and shoulder widening to allow for a safer path of travel for vehicles and bicycles alike, and new warning signage such as radar feedback signs. Additionally, 800 feet of old guardrail was upgraded to the newest standard in guardrails. Lastly, drainage improvements were implemented to help reduce flooding in the area, which will fold into a future large-scale, flood risk reduction project in the region. The safety assessment made it possible for DPW to apply for a Highway Safety Improvement Grant in 2014, which was received in 2015. The approximately $1 million grant helped fund the $1.64 million project. The remainder of the funding came primarily from the County’s General Fund, as well as the Marin County Flood Control & Water Conservation District.