Q. What is the peak hour (or 15 minute) capacity of a 12-foot wide pedestrian bridge, 175-feet long?  Our Parks Department is designing a bridge over a canal next to a new cultural center that could generate large numbers during events and want some assurance that 12-feet will be wide enough.

David Henderson
Miami-Dade MPO

A. Hi David.
I don’t have anything as technical as that. But, when we improved an old car bridge near our university, we went for the full width between the structural members (18ft). We had done a count before the structure was improved and came up with about 1200 people (bicyclists and pedestrians) in 12 hours on a spring day during school. At that time, the usable width was about 8 ft with 3 ft entrances on either end and was in a sorry condition. It was very helpful to have an existing structure there at the time, to give us some sense of typical use.

The improved structure could safely hold people standing shoulder to shoulder all the way across (according to the county bridge engineer). However, our real width considerations were more to do with whether pedestrians could stop and talk leaning on the railing and looking down at the river, and bicyclists could ride side-by-side while chatting. In other words, we looked at the bridge as a place. And a people mover.

I think that taking that use into consideration also allowed it to serve folks going to a special event, e.g., football games, concerts (the Stones came last fall and many folks used the bike/ped bridge).  If you’re going to get large amounts of event traffic, I’d push for more than 12ft. If you’ve got a couple of people leaning over the railing, watching the river (or whatever), and a bicyclist coming each way, it’s a little bit uncomfortable. We’ve got a couple of 14-ft bridges (with bulb-outs for folks who want to hang out, fish, etc). I got the idea from a bike/ped bridge on a trail near Sacramento and liked it.

Cheers!
J

PS: Here’s a bike/ped rail yard overpass we got done in the mid-90s.I believe it’s 18ft wide. It’s got bulb-outs, too.
http://www.bikeplan.com/project1.htm

Here’s a newish bike/ped bridge. I believe it’s 14ft wide (not close to the U or other major traffic generators but is part of the river-front trail system). You can’t see the bulb outs but they’re at the middle on both sides.
http://www.bikeplan.com/project2.htm

Q. Do you have comparison information/preferences/costs on various trail surfaces?

Dan H. Hatley, AICP
Principal Planner
City of North Myrtle Beach
Planning and Development

A. Hi Dan.

If you’re looking at a hard surface, that’ll be either concrete or some form of asphalt, and the price can vary in different places. Some places have lower prices for asphalt, others have lower prices for concrete. One variable to keep in mind is the price of oil, which could make concrete a relative bargain. Concrete also tends to have a longer life than asphalt, so that should be factored in. I don’t believe the life of the surface would vary by region but that could be possible. With asphalt, a major ingredient would be oil, and the prices of oil is getting a lot of publicity these days.

Your best bet is to check around your area and get an idea what surfaces people are currently using.  I’m cc’ing this to Tom Dodds, the SC State Bike/Pedestrian Coordinator, because he’s in your general area and knows local practice. Also, I’ve attached some pages about surfaces from the Wisconsin DOT bikeway guide. I primary on the project back in 2004, so it’s relatively current.

Hope this helps!

John W.

Q. Dear John,
We have 8-foot-wide off road multi-use pathways on both sides of two 4-lane county roads (pathway, buffer, 2 lanes, central median, 2 lanes, buffer, pathway). Buckwalter Parkway is about 6 miles long and Bluffton Parkway is about 8 miles long.

 

The Bluffton Town Council,  Bluffton Town Manager and Bluffton Chief of Police in South Carolina are seriously considering allowing golf carts on the Bluffton, Buckwalter and McCracken Circle pathways. Greater Bluffton Pathways believes this would be unsafe for those children and families who are biking and walking to school each day.

Karen Heitman
Greater Bluffton Pathways
Bluffton, SC

Karen, I asked Tom Dodds in the South Carolina state bicycle/pedestrian offce if he had an opinion on this situation.  Tom’s answer:

It was kind of awkward for us to weigh in on an issue on that rare road in South Carolina that does not belong to SCDOT, but we did generally. The shared use path fit the definition in the state code of laws to legally be considered a sidewalk (not a stretch–area beside road for pedestrians). The golf carts fit the definition for motor vehicles, and so we reminded the town that state law says no motor vehicles on sidewalks except at the driveways across the sidewalk. Also these particular paths were not federally funded.

Thomas Dodds, P.E.
Pedestrian and Bicycle Engineer, SCDOT

Karen, I hope that helps. 

JW

I received a question from the physical activing coordinator, Corey Wright, at the Oklahoma State Dept of Health.  Corey was consulting some partners on a Safe Routes to Schools/Community Walking Trail Project:

The community is building a 3 mile trail (4-sided rectangular). It’s an interior (never crosses a road) trail parallel to 3 roads and crossing through a pasture. The entire area inside the
trail is existing pasture with cattle and other livestock.

 They’ve planned for an 8-foot trail with a 10 to 12 foot buffer between the trail and the road, and an 8-foot buffer between is going to be removed in order to allow for this buffer space and will be replaced at the mentioned distance. The problem they’re having regards what type of fence to use.  They want to minimize the potential injury if a pedestrian/cyclist were to
contact the fence, but they also want to use something that will keep the cattle on the other side of the fence.  They are concerned not only for safety, but also for liability because some of the the trail is being constructed (with permission) on private land.  Some of the owners have expressed concern, and according to their agreement they will have a say in what type of fence material to use. Do you have any thoughts or recommendations?

 I responded that If there will be 8 feet between the fence and the edge of the trail, there shouldn’t be any problem. The design guidance available around the country varies somewhat, but those states without their own bikeway design guide use that of the American Assn. of State Hwy & Transportation Officials
(AASHTO). However, even those states with their own guides tend to agree with AASHTO’s guide for the most part.  Most guides suggest a 3 foot minimum between a path and any kind of obstruction.

With this amount of spacing, I don’t think it really matters what the fence is constructed of, although something other than barbed wire would be nice.

I also suggested widening the path itself  to 10 feet. These days, that’s considered the standard width;  8
feet is recommended in constrained circumstances. An example would be limited right-of-way, as you might see in an urban area. Even so, an 8 foot path wouldn’t be the preferred width.

John Williams

H.T. Siewers, the Greenways Coordinator for Bowling Green, Kentucky, wrote with a question
concerning shared-use path development:

We are developing a 5-mile shared-use path originating in downtown Bowling Green.  The shared-use path concept works well, mostly. Some of the route is over-land or in City parks, with very few vehicle conflict points.

However, we are unable to avoid a sidepath situation  in two 1/4 mile segments, where we plan to upgrade the existing sidewalk. We have encountered two pinch points where putting in an 8-10′ wide path is proving to be difficult.  Each of these segments is about 90′ long, and we no R/W beyond the existing 5′ sidewalk.  I cannot find any guidance in AASHTO to indicate whether such a narrowing would be acceptable. Do you have any advice on where I might seek clarification on this?

First, I questioned whther it was possible to acquire additional right-of-way, and noted that if possible it would be good to plan for such an addition so that folks don’t get the idea that the 5-ft width is permanent.

I also suggested using the League of Illinois Bicyclists’ sidepath tool, which can offer some useful guidance. It can help you determine how much a problem there will be AND what kinds of measures you can consider to reduce problems and eliminate hazards. Check it out: it’s at http://www.bikelib.org/roads/blos/sidepathform.htm

John Williams