Last year the East Bay Regional Park District completed two road-to-trail conversion projects. While very different in scope and cost, both projects demonstrate the benefits of transforming motor vehicles roadways into human-scaled trails. The natural-surface Pleasanton Ridge project was completed in the fall of 2014, and the conversion of the former Carquinez Scenic Drive into the George Miller Regional Trail was dedicated and opened to the public on November 8, 2014.
At Pleasanton Ridge Regional Park, the Park District converted several miles of 12 to 16-foot wide existing roads into 4-foot wide trails. The roads were created as part of a large-scale residential development project that was abandoned. Creating additional new trails may take several years due to the permit process, but in the meantime the District could convert these existing roads.
The Park District's Roads and Trails crew restored the natural contours of the land, reconnected the drainages above and below the former roadway, and left only a narrow-4-foot strip of trail in place of the wide road. Native vegetation and seed has been reintroduced to re-vegetate the slopes above and below the trail, and a hand crew from the American Conservation Experience spent several weeks shaping the new trail and installing erosion control measures. Volunteers from the Ivan Dickson Trail Maintenance Program and the Bicycle Trails Council also contributed. The cost was a modest $60,000, partially funded by a grant from REI.
Meanwhile, in October 2010, the Park District was awarded a $10.2 million TIGER grant from the US Department of Transportation to support the District's Green Transportation Initiative. A portion of those funds went to support the District's other "road-to-trail conversion" completed in 2014. The George Miller Regional Trail re-purposed a long-closed former state highway into a 1.7-mile segment of the San Francisco Bay Trail.
Carquinez Scenic Drive was constructed by the State of California in 1914, and transferred to Contra Costa County in the 1950's. By the 1980's portions of the road had failed, leaving a narrow strip of pathway less than four feet wide in places. The county closed the road and posted "no trespassing" signs.
Although the roadway continued to degrade and slump down towards the water, it became a popular spot for hikers and adventurous cyclists. As conditions became more unsafe, and after a number of serious accidents involving cyclists, the county and the Park District initiated an effort to repair the failed roadway and re-purpose it as a non-motorized hiking and bicycling trail.
Working with a team of experts including geotechnical engineers, civil engineers, Park District Roads and Trails staff and environmental professionals, construction documents were developed to implement the conversion. After extensive regrading of the site, 35-foot deep soldier pile walls were constructed on the downhill side of the slope, with extensive debris walls constructed on the upslope side. New drainage structures were constructed, and the subgrade was reinforced as necessary. The re-established 12-foot wide trail bed was paved using an innovated "cold in-place recycling" process, an environmentally-friendly method of reusing the existing degraded asphalt, saving over $100,000 in trucking costs. After the installation of fencing, gates and signage, the completed Bay Trail segment opened to the public at a gala celebration honoring retiring congressman George Miller on November 8, 2014.
The Park District received a merit award in the development category for the 2014 road-to-trail conversion projects at Pleasanton Ridge and the George Miller Regional Trail. The award was accepted by the trail development and roads and trails staff on April 23 at the 2015 California Trails and Greenways Conference held at Tenaya Lodge near Yosemite National Park.