The Trouble with Sidepaths

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The Trouble with Sidepaths
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Photos by Dan Burden
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What the Experienced Say

• why would you want to build them (sidepaths)?
  We stopped building them years ago because of all
  the safety problems
• - Arthur Ross
• Bike / Ped Coordinator
• City of Madison WS

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What the Experienced Say

• we (Oregon DOT) build them sparingly because of
  their operational problems
• - Michael Ronkin
• State Bike / Ped Coordinator
• Oregon Department of Transportation

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What the AASHTO Guide says

• some operational problems are likely to occur
• - AASHTO Guide for the Development of Bicycle
  Facilities pp 33-35

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AASHTO Guidance on SidepathsPages 33-35

• Some problems with paths located immediately
  adjacent to roadways are
• 1. Unless separated, they require one direction
  of bicycle traffic to ride against motor vehicle
  traffic, contrary to normal rules of the road.

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AASHTO Guidance on Sidepaths

• Some problems with paths located immediately
  adjacent to roadways are
• 2. When the path ends, bicyclists going against
  traffic will continue traveling on the wrong side
  of the street. Likewise, bicyclists approaching a
  shared use path often travel on the wrong side of
  the street in getting to the path.

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Wachtel Study ConclusionsPalo Alto, California
Bicycling direction / location Comparative
Crash Risk Bicyclists traveling on
sidewalk/pathway (even with traffic flow) 1.8
times greater risk Bicyclists traveling against
traffic flow (regardless of on-street or on
sidewalk) 3.6 times greater risk
- ITE Journal February 1996
Click on Screen to Continue
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AASHTO Guidance on Sidepaths

• Some problems with paths located immediately
  adjacent to roadways are
• 3. At intersections, motorists entering or
  crossing the roadway often will not notice
  bicyclists approaching from their right they are
  not expecting contra-flow vehicles.
• Motorists turning to exit the roadway may
  likewise fail to notice the bicyclist. Even
  bicyclists coming from the left often go
  unnoticed, especially when sight distances are
  limited.

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Photo by FDOT
Photo by FDOT
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AASHTO Guidance on Sidepaths

• Some problems with paths located immediately
  adjacent to roadways are
• 6. Many bicyclists will use the roadway instead
  of the shared use path because they have found
  the roadway to be more convenient, better
  maintained, or safer. Bicyclists using the
  roadway may be harassed by some motorists who
  feel that in all cases bicyclists should be on
  the adjacent path.

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Photo by FDOT
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AASHTO Guidance on Sidepaths

• Some problems with paths located immediately
  adjacent to roadways are
• 7. Although the shared use path should be given
  the same priority through intersections as the
  parallel highway, motorists falsely expect
  bicyclists to stop or yield at all cross-streets
  and driveways. Efforts to require or encourage
  bicyclists to yield or stop at each cross-street
  and driveway are inappropriate and frequently
  ignored by bicyclists.

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AASHTO Guidance on Sidepaths

• Some problems with paths located immediately
  adjacent to roadways are as follows
• 8. Stopped cross-street motor vehicle traffic or
  vehicles exiting side streets or driveways may
  block the path crossing.

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Sidepath Setbacks
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The risks of cycling, Dr. Eero Pasanen Helsinki
City Planning Department, Planning Division

• In the City of Helsinki (500 000
  inhabitants), we have built 800 kilometres of
  two-way cycle paths (Figure 5). More than half of
  these are the dangerous ones, located along the
  streets. It is hard to imagine that this system
  could be rebuilt. But in those countries and
  cities which are just beginning to build their
  cycling network, two-way cycle paths should be
  avoided in the urban street network.

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The Good News.
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FDOTs Sidepath Facility Selection Design Study
2005

• Fifty sidepath / sidewalk facilities
• In-depth crash analysis of sampling
• Creates crash rate prediction model
• (safety of Sidepath vs. On-street operation)
• Model results show design alternatives

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Sidepath Safety Model
? Wsp(6.311-0.465Wsp)D(0.015S-0.685-
1.528ln(L)-17.555

• where
• ? bicycle crash rate for a roadway minus
  crash rate for sidepath
• Wsp width of the sidepath
• D effective distance between the sidepath
  and the roadway (buffer width ½ sidepath
  width)
• S speed limit of adjacent roadway
• L number of through lanes on adjacent
  roadway

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Difference in Crash Rates as a Function of Path
Width
Sidepath more hazardous
The example roadway used for this analysis is a
four-lane, 45 mph (72 km/h) roadway, with a
separation to the sidepath of 10 feet (3.1 m).
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Difference in Crash Rates as a Function of
Separation from the Roadway
Sidepath more hazardous
example roadway of four lanes, 35 mph (56 km/h)
posted speed, with a sidepath width of 8 feet
(2.4 m)
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Difference in Crash Rates as a Function of
Separation from the Roadway
Sidepath more hazardous
example roadway with four lanes, 55 mph (89 km/h)
posted speed, with a sidepath width of 10 feet
(3.1 m).
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Sidepath more hazardous
example roadway of 35 mph (56 km/h) roadway, with
a separation to an eight-foot sidepath of eight
feet (2.4 m)
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