How to Get Bike Lanes When "There Isn't Enough Space"
By Steve Clark, Bicycling and Walking Program Manager
While many traffic engineers agree that bike lanes can provide for increased safety and encourage more people to try bicycling, they are often faced with roads that are seemingly too narrow to add bike lanes. In Minnesota, engineering options are also limited by state aid standards that call for travel lanes to be at least 11 feet wide.
But what if the center stripe is removed? Could that also result in safety benefits? Leading researchers say yes. The centerline tends to encourage motorists to stay the course, even if it might be prudent to slow down and give a cyclist more room by moving farther to the left.
A study conducted in Wiltshire County (2004) in the United Kingdom involving a dozen arterial roadways demonstrated that the removal of centerlines dropped speeds by as much as 7 mph with an average reduction of 3 mph. But more importantly, injury crashes were reduced by 35 percent! Today, it is Wiltshire County's policy to only stripe centerlines when deemed necessary due to curves in the roadway, sight restrictions, high- speed roads, etc.
No centerline is now standard policy in Wiltshire County, UK
This centerline policy is also in place for nearby Essex County. In addition to making their default design "no centerlines" they also add bicycle lanes which further decrease speeds by creating a visual narrowing of the roadway. Their minimum standard is (2) 5-foot bike lanes, and 11.5 feet of road space in the center for two-way travel. The volume of trucks on these modified roads can be as high as 5.9 percent.
This treatment is especially common in the Netherlands, where the bike lanes are generally painted red. Because motor vehicles may use the bike lanes when no bikes are present, the bike lane markings are dashed rather than solid lines. To distinguish these kinds of bike lanes from regular bike lanes they're called "suggestion lanes" or, in the US and the UK, "advisory bike lanes."
The City of Minneapolis is receiving national attention as the first city in the United States to introduce advisory bike lanes. (Many US cities have been experimenting with center stripe removal on non-residential roads, but not in combination with bike lanes.) Through a grant from BWTC, Minneapolis first tried this advisory bike lane treatment on East 14th Street on the southeast side of downtown.
A national first: advisory bike lanes with no centerline on East 14th Street in Minneapolis, MN
East 14th Street has parking on both sides, and ranges in curb-to-curb width from 40 to 44 feet. With the bike lanes at 6 feet in width and parking lanes at 7 feet, the amount left over for two-way auto travel ranges from 14 to 18 feet-still well above the minimum allowed by Essex County, but perhaps quite bold by US standards!
Success breeds success
Although the final report is yet to be completed on how well the advisory lanes are working in Minneapolis, to-date there have been no reported crashes or concerns from motorists, and cyclists using the facility have reported their satisfaction with it. When a bikeway project in Edina was being strongly opposed based on corresponding loss of parking, it was easy to suggest that Edina consider an advisory bike lane approach instead. Edina officials took a field trip to Minneapolis, saw for themselves how well East 14th Street was working, and then worked with TLC staff and Alliant Engineering to draft new plans for the bikeway on Wooddale Avenue. On May 15, 2012, the Edina City Council hosted a public hearing and approved the advisory bike lanes as well as the rest of the bikeway project. At the hearing, the public and elected officials were also presented with this nicely done Minneapolis video about different types of bike lanes:
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The City of Richfield has also approved advisory bike lanes with centerline removal for Bloomington Avenue. This design has been submitted to MnDOT for authorization and-like the Edina project-will be completed this year. Like the Minneapolis project on East 14th Street, the Edina and Richfield project locations will be studied both before and after the new advisory bike lanes are implemented.
Why these innovative treatments are allowed
Since there are no state aid rules that govern the striping or removal of centerlines in Minnesota, the Manual for Uniform Traffic Control Devices (MUTCD) becomes the rulebook to follow. And the MUTCD is very clear that if a road has fewer than 6,000 motor vehicles per day, no centerline is necessary. The MUTCD also contains a chapter about "preferential lanes," which includes bike lanes, and advises "a wide broken single white lane line where crossing is permitted."
Because motorists are permitted to cross the preferential (advisory) lanes, they still have the same width they had before and would conceivably behave the same if a cyclist was in that space, regardless of the markings. That is to say, motorists would carefully move around the cyclist, and if another car or truck is coming would slow down and wait if necessary. If a cyclist isn't in the preferential (advisory) lane, the motorist can drive over the lane markings as desired.
What about higher volume streets?
Researcher Tom Bertulis reports:
A Transport Research Laboratory study in the UK has shown promise for centerline removal projects for roads with volumes as high as 15,000 ADT as long as there was at least 18 feet of space in the central roadway (between the advisory bicycle lanes) for two directions of traffic. The report brings up the point that unlike speed cameras and flashing signs, the speed reducing benefit occurs over the entire length of the roadway rather than just at one location. The study summarizes the following benefits for centerline removal:
- reduces crashes over the entire route
- aids speed reduction for the length of the route
- creates more width for cycle lanes
- less striping has proven cost-effective
- is "politically" more acceptable than other more physical, traffic-calming measures
- creates an environment more amenable to non-motorized use
Bertulis also points out that the MUTCD is itself advisory, and "section 3B.01 of the MUTCD endorses relying on engineering judgment for final decisions . . . on any street layout."
In a nutshell
Advisory bike lanes offer a great solution when you can't meet ideal minimum lane widths-and also may be superior to the 10-5-7 treatment (used frequently throughout the United States, but not authorized in Minnesota). As a cyclist, having a bit more space-even 6 inches-can make a huge difference in safety (avoiding the door zone) and comfort level. And as a motorist, perceiving that you have a bit less space can foster a bit more prudence. Especially on narrow roadways, advisory bike lanes may be the win-win we've all been looking for.