Roads

Good roads for cycling are those that are designed, maintained, and policed with cyclists in mind. In the language of engineering, the bicycle should be a design vehicle. That is, road design should account for the operating requirements of bicycling. Since roads are designed to accommodate wider, taller, and faster design vehicles, most roads will also accommodate cycling.

Motorists generally leave plenty of room when passing cyclists, especially when there is no line separating them. Note that motor traffic has kept the entire width to the left of the white edge line clear of sand and debris (location: West Roxbury Parkway, Boston, Massachusetts, USA).

There are a few special considerations for cyclists:
Surface Quality Roads should be of smooth asphalt. Concrete is less desirable. Roads should be maintained to be free of holes and bumps.
Holes Slots parallel to the road, such as drain grates, can cause serious falls. These defects should be fixed.
Ridges Ridges parallel to the roadway can cause diverting falls. These types of hazards include railroad and especially streetcar tracks, seams, bridge expansion joints, and undulations.
Metal Metal is extremely slippery when wet. Metal deck bridges should have a concrete section. Metal plates installed to cover road works should be out of the way of cyclist’s normal route. At the least, warning signs should be installed.
Traffic Light Activators Wherever an intersection approach uses traffic detectors, there should be a detector loop designed and tested to be sensitive to the amount of metal in a bicycle wheel and located at all the locations where bicyclists may lawfully wait for the light to change. For more information, see Alan Wachtel
Lane Width On a road which carries a significant volume of traffic, the right hand lane should be wide enough for bicyclists and motorists to share side by side. The minimum is 14 ft (4.5 m). This sharable space includes any smooth paved shoulder. If there is on-street parking, the total width of the right-most travel lane and parking lane combined should be 24 ft (preferred), 22 ft (minimum). If it is impossible to provide these lane widths, a Share the Roads reminder sign should be posted, since safe bicyclists will be traveling in the middle of lanes that are too narrow to share side by side with motorists.
Traffic Signal Timing There should be an all-red phase sufficiently long for bicyclists to clear the intersection, even if they enter on the end of the yellow. For more information, see John Forester on Traffic Signal Clearance Time for Cyclists. See also Axel Wilke, Cyclists at Wide Intersections: All-Red Time Extension on Demand (pdf).

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5 Responses to “Roads”

  1. danc on 07 Apr 2008 at 11:15 pm

    Recommended lane width on rural road with little or no shoulder, approx 1000 vehicles per day?

    County is proposing adding 6ft shoulder intended as bikeway. Seems like a tremendous waste, since 2ft shoulder is sufficient to support the road. I don’t ride on “shoulder”, option road space with lot of debris, road grit, etc …

  2. SiteAdmin on 09 Apr 2008 at 9:10 am

    DanC, you haven’t said how wide the road is or how many lanes in each direction. Is it 6 ft on each side, or a 6 ft two-way bike way? The latter would of course be an extremely unwise option. What is the posted speed limit?
    Adding 6 ft shoulders (12 feet of paved width total) seems excessive. Assuming travel lanes of 12 feet, a 3 ft shoulder is adequate to have room to pass bicyclists without changing lanes, a 4 ft. shoulder is more generous. You could stripe it as a 14 ft. lane + 2-3 ft. shoulder if you prefer, thus mitigating the debris problems you mention by providing lane-sharing width within the travel lane (and also providing room for those bicyclists who want to travel to the right of the edge line).

  3. DanC on 09 Apr 2008 at 5:23 pm

    Road is two lanes, total 23-24 ft wide (good assumption 12ft travel lane), posted speed is 55 MPH > 70% of road, portions near residential development vary, 35-50 MPH and inside local village, 25 MPH.

    Proposal is for 6ft shoulder bikeway on each side.

    14 ft lanes + 3 ft shoulder would suit everyone. I doubt it really needed, signs and lower speed limit would help a little, very little. Creating a “pedestrian space for bikes” is unneeded and wasteful.

    Local MPO consultant, a nationally recognized bike planner notes under potential issues: The project would need to address numerous physical constraints, including drainage issues, abrupt cross-slopes, narrow bridge and presence of light poles and area targeted for shoulder widening.

    Still in shock a “recognized bike planner” consultant would recommend “shoulder bikeway”. This is a Midwest county road not in the middle of the desert where the Interstate Freeway is the only road for dozens and dozens of miles between towns.

  4. Faith Rochester Drylie on 01 May 2008 at 1:40 pm

    Yesterday in Enid OK another person riding a bicycle was hit from behind by a car while both were traveling in the same direction. This time the bicyclist was killed.

    How much longer is that old traffic law on bicycles riding with the flow of traffic going to be kept in force?

    Laws requiring a bicycle to be ridden WITH THE FLOW OF TRAFFIC were enacted in the horse & buggy days – when bicycles were considered a menace to horses!

    A bicycle being foot-pedaled with the flow of traffic moving at 30, 40, 45 or 50 MPH or better is in grave danger of being run-down! If I were to ride a bicycle it would be facing the flow traffic so I can see what is coming at me. How can you see what is moving BEHIND YOU? When you’re walking or jogging – you speed is slower than motorized vehicles – so you proceed facing the trafficde! Why don’t bicycle riders ride facing the traffic?

    I know there are two theroies on this – one being that if you’re hit by an oncoming car – the impact is harder – according to a police segeant I just spoke with. But, I would rather take my chances with the on-coming traffic. !

    How about it out there bicycle riders? Wouldn’t you feel safer riding so you can see the traffic coming at you?

    I urge you to contact your State Representative to get this law changed – either do away with it or amend it to allow the bicycle rider a choice of which side of the road to ride on!

  5. SiteAdmin on 01 May 2008 at 1:54 pm

    Faith, I think you are referring to this:

    http://www.enidnews.com/localnews/local_story_121003400.html

    Bicyclist is critical

    Staff reports

    An Enid man was hospitalized in critical condition Tuesday after he was hit while riding his bicycle on Oakwood Road.

    David Lee Harrison, 46, was taken to St. Mary’s Regional Medical Center, according to an Oklahoma Highway Patrol report, and admitted in critical condition with head and trunk injuries.

    The accident happened at 5:40 p.m. on Oakwood, three-tenths of a mile south of Wheat Capital.

    Harrison was riding his Allez Elite Vittoria bicycle south on Oakwood when he was hit by a 2008 Toyota Avalon driven by Duard Spleth, 84, of Waukomis, according to the report.

    Spleth told officials he was driving south on Oakwood when looked down to adjust the air conditioning controls on the steering wheel and hit Harrison’s bicycle from behind. Harri-son was thrown an unknown distance in the collision, according to the report.

    Trooper Jeff Jech, who investigated the accident, said a witness told him she passed both the bicyclist and Spleth’s vehicle then looked in her rearview mirror and saw the bicycle fly into the air.

    Spleth was not injured, according to the report.

    The cause of the accident is listed on the report as distraction inside vehicle.
    ———————————-

    Your solution — Let cyclists ride against traffic — would not necessarily have prevented this collision and surely causes many more.

    Other responses —
    is it okay to be looking at the air conditioning controls instead of the road? Is that just how people drive or is that negligence?

    Is the motorists physical or mental condition (at age 84) a factor? Should this person be driving?

    A dangerous motorist (either incapacitated or negligent) can kill bicyclists — or just as easily pedestrians or other motorists or his or her self or passengers.

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