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Solving wheelchair accessibility issues for trail bridges

The weak link in making trail bridges accessible is the point where the deck joins the approach. To improve accessibility for our trails we have a great variety of bridges with relatively flat, smooth decks. One problem area is the joint between the bridge structure and the trail surface. Typically these are two different materials, such as a wood bridge deck meeting a dirt trail. Or in an urban situation, a hunded-foot long span meets a concrete or asphalt trail. To do this without creating a "vertical obstruction" (in ADA terminology) can be challenging, and may require a patch or filler. Fixing these potential barriers to wheelchairs will also other trail users, because a lip or gap at a bridge can cause pedestrians to trip or bicyclists to lose control. See both problems and solutions in the photo gallery below.

See bridge manufacturers in the American Trails Business Directory

Click on any photo to see it full size along with more information:

(photos by Stuart Macdonald except as noted)

Good example of accessible trail bridge meeting natural surface trail, where both bridge is actually a little below the trail grade, so trail material does not wash away from the bridge; photo on Barclay Farm National Recreation Trail, from Cherry Hill Township, NJ

The classic problem on dirt trails, where the bridge itself is above the trail grade and the surfacing material wears away, leaving a step; Woodpecker Loop Trail in Finley National Wildlife Refuge, OR, photo by Stuart Macdonald, 15 Sept 2009

A heavy timber extends along the bridge approach to retain the trail surfacing material (crushed concrete), Easter Seals Handicamp, Empire, Colorado; photo by Stuart Macdonald, June 2008

Retaining timber is higher than the bridge deck, keeping the trail surfacing material even with the bridge, Rocky Mountain Arsenal National Wildlife Refuge, CO; photo by Stuart Macdonald, 7 Nov 2009

Rock retaining wall holds trail surfacing material at wood bridge approach on Emerald Bay Trail at Lake Tahoe, CA; photo by Stuart Macdonald, 20 Sept 2007

Concrete retains trail material and forms a landing for the bridge approach in Bible Park, Denver, CO; photo by Stuart Macdonald 4 Dec 2009

Another view of the concrete bridge approach; soil still tends to wash away or compact, requiring occasional maintenance; Bible Park, Denver, CO

Asphalt trail meets boardwalk; both surfaces are level, at Trail of the Sentinels National Recreation Trail, WA; photo by Stuart Macdonald, 12 Oct 2006

Concrete trail makes a good connection to wood boardwalk, Finley National Wildlife Refuge, Oregon; photo by Stuart Macdonald, 29 Aug 2008

Concrete trail meets grade of concrete bridge with expansion joint in San Diego's Balboa Park at Park Blvd. overpass; photo by Stuart Macdonald, 5 Sept 2009

At the other end of same concrete bridge, the trail doesn't quite meet grade, requiring an asphalt patch to avoid abrupt vertical obstruction; Balboa Park, San Diego; photo by Stuart Macdonald, 5 Sept 2009

Another example of asphalt patch; in this case the obstruction is at the concrete sill which the bridge abuts against; Little Dry Creek Trail, Arvada, CO; photo by Stuart Macdonald, August 2007

Steel plate fills the vertical gap between sections, Seattle, WA; photo by Stuart Macdonald, Sept 2008

Trail has to make abrupt right angle turn to cross stream, as well as climb to bridge height, Buena Vista, Colorado; photo by Stuart Macdonald, 1 July 2008

Concrete sill doesn't solve the problem of keeping trail material up to bridge grade, Buena Vista, Colorado; photo by Stuart Macdonald, 1 July 2008

Floating bridge with multiple joints is a problem with no easy solution, Arboretum Waterfront Trail, Seattle; photo by Stuart Macdonald, Sept 2008

Steel deck to concrete with wood transition, but bridge sections are obtacle-free, Arboretum Waterfront Trail, Seattle; photo by Stuart Macdonald, Sept 2008

Otherwise accessible trail is compromised by steps at transition from one bridge section to another, Arboretum Waterfront Trail, Seattle; photo by Stuart Macdonald, Sept 2008

Worst choice: wood chips to fill in corner between sections of floating bridge, Arboretum Waterfront Trail, Seattle; photo by Stuart Macdonald, Sept 2008

Transition from steel deck to trail; wood chips tend to compact leaving a joint no matter how often they are topped up, Arboretum Waterfront Trail, Seattle; photo by Stuart Macdonald, Sept 2008