Sep 012012

Type 1a Trail: Custis Trail in Virginia

Years ago, American planners decided to divide bikeways into three types:

  • Class I: Off-road paths  (aka bike paths, shared use paths, or multi-use paths)
  • Class II: On-road bike lanes
  • Class III: Shared roadways

This categorization implied that off-road paths were superior to bike lanes, and that bike lanes were superior to roads without bike lanes.  Maybe that was the thinking at the time.  But it’s well accepted now that shared use paths carry risks of their own and are not suitable for all cyclists at all times.    So in Montgomery County planners now use the terms “shared use path”, “bike lanes”, and “signed shared roadway” (SSR), respectively.   The terms Class I, II, and III aren’t inaccurate, just out of common use.

Whatever the categories are called, the first category is obviously very broad and people need to realize that not all shared use paths are created equal.  I’ve had to tell planners, engineers and elected officials many times that shared use paths can vary dramatically in terms of safety, usefulness and appeal.  Some paths are spectacular uninterrupted hiker-biker trails and others are nasty sidepaths with busy side street and driveway crossings every 50 feet.  Too often decision-makers accept the latter when plans call for the former.

So I came up with a sub-categorization of shared use paths, kind of as an exercise and possibly as a means to clarify the differences in quality between some paths and others.  I call the path classes 1a, 1b, 1c, 1d, and for good measure 1u (u as in urban).  Yes, a is the best and d is the worst.  Here they are:

1a: EXCELLENT QUALITY: Path is almost entirely free of at-grade crossings.  If it’s a sidepath, it’s well-separated from the adjacent roadway.  Includes “hiker-biker trails” through woods and stream valleys, rails-to-trails facilities, and trails along freeways.  (Stream valleys, railway beds and freeways are well-suited because cross-streets usually go over or under them). The path is more than wide enough for most uses (usually 10′ or more).  Examples: Capital Crescent Trail, Matthew Henson Trail, Custis Trail.

Class 1a: Matthew Henson Trail in Aspen Hill

Class 1a: Route 29 Trail under the ICC

1b: GOOD QUALITY: A sidepath along a limited access arterial road with widely-spaced intersections and relatively few grade crossings.  Mostly separated from the street by a grass strip or other buffer so that cyclists can’t fall into the street.  Path width is adequate (8′ or more).  Examples: Millennium Trail along West Gude Drive, Great Seneca Highway sidepath.

Class 1b: Millennium Trail on West Gude Drive

1c: FAIR QUALITY: Typical suburban sidepath that crosses streets and/or low-volume driveways on a frequent basis. Mostly buffered from the street but may have some stretches with inadequate buffer and/or width (not both).  This is the most common shared use path type in suburbia, often added to new roads when they’re built.  Examples: Millennium Trail along Wootton Parkway, most of the sidepaths in Germantown, many in King Farm, and countless other sidepaths.

Class 1c: Millennium Trail along Wootton Parkway

Class 1c trail crossing a roundabout

1d: POOR QUALITY: Sidepaths with a great number of high-volume street crossings, difficult intersections, commercial driveways and other hazaradous conflict points with motor vehicles.  Category also includes narrow sidepaths with no buffer between the path and the street.  Paths along commercial strips lined with shopping centers and gas stations fall into this category, as do sidepaths on major roads lined with one residential driveway after another.  Sometimes the trails are interim trails, especially those that seem indistinguishable from sidewalks.  Examples: Millennium Trail along East Gude Drive, Bethesda Trolley Trail along Woodglen Drive.

Class 1d: Millennium Trail on E. Gude Drive. Lots of commercial driveways, no separation from a busy 6-lane road.

Class 1d: Bethesda Trolley Trail along Old Georgetown Rd. Too narrow, too close to 6-lane road.

This scheme didn’t seem to capture the special nature of sidepaths along urban streets which otherwise would fall into class 1d, so I created a class 1u:

1u: URBAN TRAILS: These have a high number of street/driveway crossings, just like most class 1d trails, but they serve a useful role in urban contexts by essentially letting cyclists ride on the sidewalk.  Various streetscape elements can be provided to mitigate conflicts with cars (painted crosswalks, signs) and pedestrians (sidewalk layout, dividers, pavement treatments, signs, markings, etc).  Compared to typical suburban sidepaths, user expectations are different and cyclists tend to keep their speed down.  Drivers are traveling more slowly and hopefully are more attentive to what’s happening on the sidewalk as they execute turns.  Urban sidepaths tend to look a lot like two-way cycletracks at sidewalk level, except the latter are only for bicycles.  Examples: Silver Spring Green Trail, parts of the Metropolitan Branch Trail.

Class 1u trail (essentially a two-way cycletrack) well-integrated into a sidewalk in Colombia

Class 1u Silver Spring Green Trail on Wayne Ave.

Jack Cochrane

Chair, MoBike

  7 Responses to “Trail Typology”

  1. I like it. I agree there is a big difference between the millennium trail on east vs west gude dr.

  2. Yep, the Millennium Trail is a microcosm of the best and worst. Parts of it are great, parts are so-so, and the East Gude Drive part is horrid.

  3. I would actually disagree with this classification because it assumes that all multi-use trails that are completely separated from the road are created equal. For example, there are many, many parts of the Rock Creek Trail that are completely separated from the road that I think are extremely dangerous because they are steep, narrow, and curvy, such as near the zoo in D.C. and near Aspen Hill park in Rockville. I’m much more nervous biking on those and having the chance of someone coming around a turn too fast or a pedestrian not paying attention than I am of riding on any part of the Millennium Trail. I have similar issues with the part of the Bethesda Trolley Trail going through NIH.

  4. I agree that some separated trails are pretty bad. We’ve tried to get NIH to widen their portion of the BTT. If you have any ideas on how to account for bad trails in this classification system, let me know. 1a requires width as I mentioned. Maybe it just gets the 1d rating? Or maybe it’s not a trail at all — just a sidewalk.

    • Not only is the path narrow but many of the transitions at cross walks feature sharp curbs or poles directly in the path. I would like to know who is the safety officer for NIH. I suspect that no regular user of the BTT adjacent to NIH has not, frequently, had an NIH employee try to run them over in the cross walk.

  5. Note: People posting a comment on CycleMoco for the first time are moderated. After that comments are not moderated..

  6. Does AASHTO or someone have a general procedure for rating maximum safe speed of trails, considering all of the factors that determine safe speed, including trail width, cross streets and driveways, pavement grade, curves and dips, and visibility? That would be analogous to highways, and provide a pretty good indication of trail quality. If not, maybe a good proxy would be your average speed riding each trail (in a controlled and probably solo ride where you consciously decided to ride very safely and in the same manner for each trail).

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