Monday, May 7, 2012
 

VDOT guidance on use of sharrows

VDOT recently issued guidance on use of the Shared Lane Markings (sharrows) and Bicycles May Use Full Lane signs (BMUFL) in the Northern Virginia District. The formal title is BIKES MAY USE FULL LANE Signs and Shared Lane Markings, Northern Region Traffic Engineering Practice. It was written by Randy Dittberner, VDOT Traffic Engineer and dated April 10, 2012.

The guidance is meant to clarify how the devices should be used in our area. This is an important step in the implementation of these devices. We've heard that both devices will be installed on a few roads in Fairfax in the coming weeks. There will also be publicity to inform the public about why the devices are being used and what they mean.

From the guidance:
GENERAL CONSIDERATIONS

In order for these devices to be effective, they must not be overused, but rather limited to the locations where motor vehicle traffic, bicycle traffic, and roadway conditions combine to create the greatest need. As such, the following considerations apply when evaluating a roadway for the possible application of these devices:
  • Neither device shall be used on roadway segments with bike lanes, since a bike lane eliminates the need for these devices.
  • Neither device shall be used on roadway segments with paved shoulders 4 feet or more in width. Although cyclists are permitted to use the travel lane even where shoulders are present, these devices may inappropriately discourage some cyclists from using the shoulder.
  • Both devices should be limited to roadway segments designated by the local jurisdiction’s bicycle plan as part of its bicycle network.
  • Roadway segments with low traffic volume, less than 3,000 vehicles per day, should not need these devices, because they usually offer a sufficient cycling environment.
  • Neither device should be used on roadway segments with traffic volume greater than 30,000 vehicles per day or speed limits greater than 35 mph. Cyclists are generally permitted to use high-volume, high-speed roadways, but these devices may encourage novice cyclists to travel on a roadway above their skill level.
  • Both devices should be limited to roadway segments where travel lanes are delineated with longitudinal pavement markings or other methods. (Neither device should be used on undivided unmarked roadways.)
There is also specific guidance for the signs and sharrows:
BIKES MAY USE FULL LANE SIGN

BIKES MAY USE FULL LANE signs shall be used only where bicyclists are permitted by the Code of Virginia1 to use the full lane. The Code of Virginia permits bicyclists to use the full lane in a “substandard width lane,” which is defined as “a lane too narrow for a bicycle . . . and another vehicle to pass safely side by side within the lane.”

Where this condition is the reason for installing the sign, its use should be limited to roadway segments where the combined width of the right-most travel lane and any paved shoulder is 10.5’ or less, excluding the gutter pan, if any.

In order to avoid overuse of the signs that would reduce their impact and effectiveness, BIKES MAY USE FULL LANE signs should be limited to roadway segments used frequently by cyclists, or where cyclists report being intimidated by nearby motor vehicle traffic.
We are a little concerned that the signs only be used on roads 10.5' or less. Most of the roads in Fairfax are 11' or greater. This guidance seems to greatly reduce the number of locations where the signs could be used.
SHARED LANE MARKING

Following are examples of locations that may benefit from Shared Lane Markings:
  • Shared Lane Markings can provide guidance where there is a gap in or a terminus of an otherwise continuous bike lane, where constraints such as roadway width preclude the addition or extension of a bike lane.
  • Where on-street parking is permitted and frequently occupied, Shared Lane Markings can help cyclists choose an appropriate lane position, rather than riding too close to the doors of parked cars.
  • Where a roadway segment is wide enough for a bike lane in only one direction, the bike lane can be installed in the uphill direction and Shared Lane Markings can be used in the downhill direction, where cyclists are more likely to travel near the speed of motorists and may need to ride farther from the curb to have enough reaction time.
However, Shared Lane Markings shall not be used in any of the following situations:
  • As a substitute for a bike lane where conditions permit a bike lane to be marked
  • To provide wayfinding guidance to cyclists
  • To designate a roadway as a bicycle route
  • On a shared-use path or other facility where motor vehicle traffic is prohibited
  • In an exclusive turn lane, where they could communicate that cyclists are permitted to use the lane to travel straight through an intersection instead of using the appropriate through travel lane
The layout of Shared Lane Markings shall not vary from the figure depicted above.

When roadway segments with Shared Lane Markings are repaved, the segments should be evaluated to determine whether the pavement could be widened enough to mark a formal bike lane. Roadways with Shared Lane Markings should be a high priority for shoulder widening. If it is infeasible to widen the pavement, the segments should be evaluated to ensure that traffic and roadway geometric conditions continue to support the use of Shared Lane Markings.

OTHER CONSIDERATIONS

A BIKES MAY USE FULL LANE sign and a Shared Lane Marking should not normally be used on the same roadway segment, unless extreme conditions, such as a documented volume of heavy cyclist traffic and severe roadway geometry, are present to a degree that using both devices together would provide a significant additional benefit to the traveling public.

Labels: , , , , , ,

Comments:
I agree that it's unreasonable to limit BMUFL signs to locations with travel lanes narrower than 11 feet, since 11-foot to 13-foot travel lanes are clearly not safely sharable laterally between a bicyclist and any auto.

Also, Arlington County has installed both sharrows and BMUFL signs in the same location with excellent results.
 

Post a Comment

Contact FABB via email: info@fabb-bikes.org

Subscribe to the
FABB e-newsletter


Subscribe to posts:
[Atom 1.0] or [RSS 2.0]





  Bike to Work Day 2015 at Wiehle Station

  Transportation choices

This page is powered by Blogger. Isn't yours?

Archives

  • December 2018
  • November 2018
  • October 2018
  • September 2018
  • August 2018
  • July 2018
  • June 2018
  • May 2018
  • April 2018
  • March 2018
  • February 2018
  • January 2018
  • December 2017
  • November 2017
  • October 2017
  • September 2017
  • August 2017
  • July 2017
  • June 2017
  • May 2017
  • April 2017
  • March 2017
  • February 2017
  • January 2017
  • December 2016
  • November 2016
  • October 2016
  • September 2016
  • August 2016
  • July 2016
  • June 2016
  • May 2016
  • April 2016
  • March 2016
  • February 2016
  • January 2016
  • December 2015
  • November 2015
  • October 2015
  • September 2015
  • August 2015
  • July 2015
  • June 2015
  • May 2015
  • April 2015
  • March 2015
  • February 2015
  • January 2015
  • December 2014
  • November 2014
  • October 2014
  • September 2014
  • August 2014
  • July 2014
  • June 2014
  • May 2014
  • April 2014
  • March 2014
  • February 2014
  • January 2014
  • December 2013
  • November 2013
  • October 2013
  • September 2013
  • August 2013
  • July 2013
  • June 2013
  • May 2013
  • April 2013
  • March 2013
  • February 2013
  • January 2013
  • December 2012
  • November 2012
  • October 2012
  • September 2012
  • August 2012
  • July 2012
  • June 2012
  • May 2012
  • April 2012
  • March 2012
  • February 2012
  • January 2012
  • December 2011
  • November 2011
  • October 2011
  • September 2011
  • August 2011
  • July 2011
  • June 2011
  • May 2011
  • April 2011
  • March 2011
  • February 2011
  • January 2011
  • December 2010
  • November 2010
  • October 2010
  • September 2010
  • August 2010
  • July 2010
  • June 2010
  • May 2010
  • April 2010
  • March 2010
  • February 2010
  • January 2010
  • December 2009
  • November 2009
  • October 2009
  • September 2009
  • August 2009
  • July 2009
  • June 2009
  • May 2009
  • April 2009
  • March 2009
  • February 2009
  • January 2009
  • December 2008
  • November 2008
  • October 2008
  • September 2008
  • August 2008
  • July 2008
  • June 2008
  • May 2008
  • April 2008
  • March 2008
  • February 2008
  • January 2008
  • December 2007
  • November 2007
  • October 2007
  • September 2007
  • August 2007
  • July 2007
  • June 2007
  • May 2007
  • April 2007
  • March 2007
  • February 2007