Rail-trails attract a diverse set of users (pedestrians, cyclists, equestrians, etc.) and often seek to accommodate them all. Typically, permitted trail uses are determined in the rail-trail planning phase, and good trail design balances the needs of the users with the unique characteristics and goals of the project.
Trail designers often look to the American Association of State Highway and Transportation Officials' (AASHTO) design guidelines as the standard for multi-use trail widths. AASHTO recommends a minimum of 10 feet for multi-use trails; however, where heavy use is anticipated, a 12 to 14-foot width is recommended.
Occasionally, providing separate, parallel paths (or treads) for different users may be desirable. For example, a primary, hard-surfaced path can be provided exclusively for bicyclists, with softer shoulders set aside for pedestrians and equestrians. Single shoulders should be at least 5 feet wide, while dual shoulders (one on each side) should be between 2 and 2.5 feet wide.
Types of Trail Users
In addition to trail width, accommodating the many users of a multi-use trail requires planning for surface type, vertical clearance and trail amenities. Some uses may seem incompatible with the desired design and feel of the trail; however, when properly planned, trails can effectively accommodate a variety of users.
Pedestrians include walkers, hikers, joggers, runners, bird watchers and dog walkers. These users tend to have fewer design requirements than other users. Most prefer softer surfaces (such as rubber, mulch or crushed stone) to lessen impact on their knees, though some users, such as power walkers and those pushing strollers, may prefer more compact surfaces. The minimum recommended vertical clearance for pedestrians is 8 feet.
Benches, drinking fountains, shaded rest areas and restrooms are valuable amenities to pedestrians. Where dogs are permitted, consider providing dog-friendly drinking fountains, bag dispensers and trash bins to encourage people to pick up after their dogs.
Bicyclists fall into a number of subcategories, including recreational, commuting and touring. The AASHTO’s Guide for the Development of Bicycle Facilities is viewed as the national standard for bikeway design, and you will most likely have to adhere to its guidelines if your trail project receives federal or state transportation. Consult your local department of transportation before beginning design. Bicyclists generally prefer hard surfaces and require a vertical clearance of at least 8 feet, with 10 feet needed for overpasses and tunnels.
Adequate sight distances for cyclists are critical for user safety; AASHTO recommends that multi-use trails provide a minimum sight distance of 150 feet. Ideal grades over long distances for bicyclists are less than 3 percent (typical for former railroad corridors), although up to 5 percent is acceptable. In addition to the amenities suggested for pedestrians, bicycle racks and bicycle lockers located at transit nodes or places of employment are recommended.
Mountain bikers are considered a separate user group, as they tend to seek out more challenging trails with steeper grades and uneven surfaces. With mountain bikers making up a large segment of the bicycling population, it is wise to accommodate this group with mountain bike parks along the rail-trail. The trail can be used to access these parks, which feature rugged terrain and challenging obstacles. Contact your local mountain biking organization or the International Mountain Bicycling Association for more information on constructing mountain bike parks.
Suitable trails for equestrian users, also known as horseback riders, have become increasingly hard to find, particularly close to urban areas. Many trails prohibit equestrian use, fearing conflicts with other users and damage to the trail surface. However, with proper design, a multi-use trail can accommodate equestrians while minimizing user conflicts.
Hard surfaces (asphalt and concrete) and coarse gravel can injure horse hooves, so equestrians prefer loose or compacted dirt trails. If you plan to use a hard surface, consider placing a softer, separate 5-foot-wide tread for horses alongside the main path. Vertical clearance should be at least 10 feet, with a horizontal clearance of at least 5 feet. Sight distance should be at least 100 feet, and proper signage is needed to indicate which user has the right-of-way priority.
It is advised to consult local equestrian groups to develop equestrian-friendly facilities. Horses often prefer water crossings to bridges. If this isn’t practical, provide mounting blocks at the ends of bridges so that riders can dismount and lead their horses across the structure. In addition to the standard amenities for human users, parking and staging areas, water for horses and hitching posts at any area where the rider may stop to take a break (rest areas, restrooms, etc.) should be provided.
Cross-county skiers are recreational skiers who traverse the countryside rather than make downhill runs. Many multi-use trails that accommodate pedestrians, bicyclists and equestrians during warmer months are ideal for cross-country skiing during winter months. A minimum of 6 inches of snow on a trail offers excellent skiing without damaging the trail or ski equipment. If the trail sees other winter use, cross-country skiers will often ski off to the side to avoid having their tracks trampled.
If you anticipate heavy ski use on a long-distance trail, consider placing warming shelters along the trail. These can be simple structures that provide a fireplace and small shelter.
Paved multi-use trails that accommodate pedestrians and bicyclists are likely to attract inline skaters as well. Inline skaters require the same trail width (minimum of 10 feet) and hard surfaces as bicyclists and the same vertical clearance as pedestrians (8 feet). Consider locating benches at trailheads to facilitate changing in and out of skates.
Some trails, especially in rural areas, also accommodate all-terrain vehicles (ATVs) and snowmobiles. Trails that receive federal funding (except through the Recreational Trails Program) may not permit ATV use, though in some instances, snowmobiles are acceptable. For more information, contact your state trails administrator. When allowed, snowmobiles can be used on multi-use trails with as little as 6 inches of snow without causing much damage to the trail surface.
Trails should be at least 8 to 10 feet wide to accommodate one-way traffic. For two-way traffic, trail width should be at least 12 to 14 feet. As motorized users travel at much greater speeds than other users, the trail should be free of obstacles and provide good sight lines with a minimum sight distance of 400 feet. Branches and other debris should be cleared across at least 2 feet on each side of the trail with a 10-foot vertical clearance; be sure to factor in anticipated snow levels. If the trail features bridges or tunnels, they must be at least 8 feet wide with a minimum carrying capacity of 5 tons. Intersections can be dangerous for these users, so it’s best to double the trail width at intersections to improve maneuverability where possible.