This is an excerpt from a report I wrote for another park 10 years ago. The dates but not the principles have changed, and some bosque-specific information has been added.

I. Multi-Use Trails

“Multi-use trail” is, in practice, a bicycle commuter highway that joggers and walkers shun. The asphalt surface injures joggers’ ankles, knees, and hips. Given a choice, they prefer to run on the earth alongside existing multi-use trails, according to the only recent survey on conflicts between users of  multi-use trails, done in Albuquerque, N. M.[i]

Two thirds of walkers on multi-use trails fear cyclists, according to a federal report on conflicts between users of multi-use trails. Bicycle traffic volume on weekends appears to outpace rush hour traffic all day, thus mimicking weekend auto traffic statistics.[ii] It also corroborates the Albuquerque survey finding that user conflict on multi-use trails worsens on weekends.

In the 10 years since the foundation of multi-use trails, there have been only two studies on conflicts between users, according to the 300-plus pedestrian traffic experts on the international e-mail listserv, Pednet.

The first study of conflicts between multi-use trail users was commissioned by the Department of Transportation when the funds were set aside nine years ago.[iii] User conflict was seen as the number one problem with multi-use trails. This prediction has proved correct. Recently, the city of Albuquerque, N.M. tallied the conflicts between the 368 respondents to a survey of users of their multi-use trails. The city trails coordinator concluded, “The only solution is either separated paths or wider paths, say 14 feet.  Otherwise it will forever be a problem.”

Lacking other precedent, four well-established principles of urban planning and traffic engineering are useful to inform speculation on the future of a multi-use trail.

The first is the certainty that widening induces travel. Senior researchers of the National Academy of Sciences (U.S. government academics, not the highway lobby, nor greens) have authoritatively concluded that every 10 per cent increase in the width of a highway leads directly to a 3.3 per cent increase in the number of vehicles traveling upon it.[iv]  This is a revolution in thinking previously formed by the highway lobby credo, “ease traffic congestion” by building more roads and widening extant ones. What actually happens is that gridlock is not eased, simply widened.

One career environmentalist and long-term observer of the bosque estimates 3 to 5 people an hour currently walk the main bosque path on a summer day.

 According to the city, “an average of 780 bike riders per day pass under I-40 on the Paseo del Bosque”. Given a 12-hour day, that’s 65 bicycle riders an hour, more than one a minute. If the proposed bosque path is connected to the existing Paseo del Bosque trail, pedestrian traffic engineers calculating the environmental impact of a 10-foot-wide surfaced multi-use trail through the bosque would need to take this high volume of use on a parallel path into consideration. As far as I know, no bosque path usage or environmental impact study has been done. But these figures, from 3 to 5 an hour to one a minute, suggest and can be used as ballpark parameters for estimating induced traffic on the proposed trail and its impact on pedestrians, including bosque fauna attempting to cross the trail at twilight, or those inclined to depart high levels of human activity.
Immanent calls by cyclists and bladers for future widening of what is officially designated “multi-use” will almost certainly ensue, as the Albuquerque survey suggests. Conflicts between users are intractable, as the federal report foresaw before there were any trails or users, and as the Albuquerque survey corroborates nearly a decade later.

Second,[v] an urban planning concept known as “eyes on the street” comes into play. A Jane Jacobs concept, the idea is that crime decreases as the number of pedestrians on foot increases. [I wrote this whole document about a proposed path through a neighborhood park in Washington, D.C.. I’m leaving this part in, because while specific to the D.C. site, it also explains in detail what will happen in the Bosque when pedestrians are chased out:

[The Rock Creek Park bicycle commuter path usage survey conducted by the Happy Trails Caucus shows walkers shun the bikeway. The bikeway which crosses west of the creek, and passes under the P Street bridge has sheltered repeated attacks. The first series of assaults were by an ice-pick-wielding bicycle thief (1994). The second series were by a rapist intent on assaulting lone female joggers (1996).  This crime zone was created – according to this rubric of eyes on the street – due to the fact that walkers shun it, and that it is out of the line of sight of motorists. Thus, the establishment of a multi-use trail in Rose Park would possibly create a crime zone by eliminating walkers from the mix, as they have been eliminated from the mix on the Rock Creek Park bicycle commuter path, for which a link is sought to Rose Park.

[If someone knows a similar crime zone on Albuquerque’s cyclist trails that demonstrably, with newspaper clips of the crimes, has become dangerous because pedestrians have been forced out of the area by cyclists, please do the research and make the point at the public meetings Sept. 4 and Sept. 18 on the mayor’s plan for the bosque. If you could give me your sources of info and corroboration, in a formal bibliography, I’d be delighted to include it here with a credit to you.

[In ABQ the Plan, city public safety authorities are quoted (p. 32) on this principle, saying an increase of visitors to the park will make it safer. They seem not to have taken into account that an increase of cyclist visitors, who are not considered eyes on the street, will run off all other law-abiding users of the proposed trail.]

 

Third, traffic engineers calculate that each pedestrian on foot requires only 1.5 feet of  what they term “shy space”. As speed increases, so does the amount of shy space required. Thus, two pedestrians walking very quickly side by side would each require 3 feet of shy space, for a total of 6 feet of shy space. A sidewalk of 6 feet wide would thus be recommended, under the best practices rubric, to accommodate just two fast-moving walkers. A multi-use trail would add even faster-moving cyclists and bladers to this mix. The proposed bosque multi-use trail is 10 feet wide. Given just two fast-moving walkers abreast, that leaves four feet of shy space for cyclists and bladers. Cyclists are usually calculated as needing six to eight feet of shy space apiece. No reasonable plan would increase bicycle traffic while expecting cyclists and bladers to confine themselves to four feet of shy space.

The fourth possible outcome for a multi-use path in the bosque is known to pedestrian traffic engineers as the “barrier effect.” As with Robert Moses’ Bronx Expressway,  a broad asphalt surface with induced traffic traveling upon it prevents pedestrians from crossing to the other side. The barrier effect creates dead space on the side of the highway to which people do not cross. Thus, a multi-use path could halve the space people use, could create a dead zone in the half of the park to which no one wishes to cross. In the bosque, amphibians like the soft-shell and painted turtles who live in the water and emerge to lay eggs on land have a low tolerance to lack of cover. A 10-foot paved trail along the river’s edge would prove a barrier to migration for reproduction that the turtles would be unlikely to overcome. According to one long-term scientific observer of the bosque, a 10-foot paved path would create a barrier effect which could drive amphibians from the bosque.

Click and scroll down for photographs and descriptions of the turtles of New Mexico. Save their species. No road through the bosque.
https://plus.google.com/u/0/108460088402018418673/posts

###



[i] Private communication from HNL.

Here in Albuquerque, New Mexico we have over 80 miles of paved multi-use trails.  The weekends are the worst times for user conflicts due to the varying speeds of users,i.e. rollerblaers and bicyclists  vs. walkers and runners.  The only solution is either separated paths or wider paths, say 14 feet.  Otherwise it will forever be a problem.

We recently completed trail counts and surveys. 368 surveys were collected and many of the comments were “please make the trail wider and smoother”, and this was from rollerbladers and bicyclists.  Most walkers and runners would actually prefer an unpaved surface, since it is easier on your hips, knees, and ankles vs. walking or running on concrete or asphalt.

This is obviously not a full blown study but I can assure you that the data

we’ve collected here over the past two weekends is indicative of the needs and conflicts which exist nationwide on trails whether they be in urban or more off-road/wilderness areas.

Hope this is useful and helpful.

Henry N. Lawrence III
Associate Planner, Trails Coordinator
City of Albuquerque
Parks and Recreation

[ii] Sipress, Alan. (February 19, 2000.)  Saturday Saturation; Traffic Volume on ‘Off’ Day Now Outpaces Weekday  Rush Hours in Region. The Washington Post.

[iii] http://world.std.com/~jimf/biking/conflicts.html

That’s a dead link from the original document I wrote 10 years ago. It may refer to this, but I doubt it.

A study of readers of Backpacker magazine found that over two-thirds felt the use of mountain bikes on trails was objectionable (Viehman 1990). Startling other trail users, running others off the trail, being faster and more mechanized, damaging the resources, causing erosion, frightening wildlife, and “just being there” were the biggest concerns (Kulla 1991; Chavez, Winter and Baas 1993). Keller (1990) notes that brightly colored clothes, a high-tech look, and the perception of a technological invasion can all be sources of conflict felt by others toward mountain bikers.

http://www.fhwa.dot.gov/environment/recreational_trails/publications/conflicts_on_multiple_use_trails/conflicts.pdf

[iv] Sipress, Alan. (January 13, 2000.) More Lanes Better? Not Necessarily; Traffic Increases, Studies Find. The Washington Post.

Fulton, Lewis M., et al. (April, 2000.) A Statistical Analysis of Induced Travel Effects in the U.S.
Mid-Atlantic Region. Journal of Transportation and Statistics 3, 1. 
http:// www.bts.gov/jts/V3N1/vol3_n1_toc.html

Noland, Robert B., and Lewison L. Lem. Induced Travel: A Review of Recent Literature and the Implications for Transportation and Environmental Policy. Paper to be presented at the European Transport Conference, Sept. 2000. London: click Research, then Current Working Papers. Centre for Transport Studies, Imperial College of Science and Medicine, 2000.
http://www.cts.cv.ic.ac.uk/

Noland, Robert B., and William A. Cowart. (August, 2000.) Analysis of Metropolitan Highway
Capacity and the Growth in Vehicle Miles of Travel, forthcoming in the Journal of Transportation and Statistics. London: click Research, then Current Working Papers. Centre for Transport Studies, Imperial College of Science and Medicine, 2000.

http://www.cts.cv.ic.ac.uk/staff/wp1-noland.pdf

[v] For “eyes on the street”, “shy space” and “barrier effect” outcomes, see the most recent best practices guide recommended by the experts at Pednet: Pedestrian and Bicycle Planning: A Guide to Best Practices, Victoria (B.C.) Transport Policy Institute. Their director, Todd Litman, is thought by senior pedestrian traffic analysts to be among the most solid analysts now at work.

http://www.vtpi.org

Advertisements