Cornell Local Roads Program

Shared Lane Markings for Your Toolkit

To varying extent, bicycles will be used on all highways where they are permitted. Bicycle-safe design practices in your toolkit include bicyclesafe drainage grates and bridge expansion joints along with smooth pavements and adequate sight distances. Width is the most critical variable affecting the ability of a roadway to accommodate bicycle traffic. In order for bicycles and motor vehicles to share the use of a roadway without compromising the level of service and safety for either, the facility should provide sufficient paved width. This width is sometimes achieved by providing wide outside lanes (in urban settings) or paved shoulders (in more rural settings). Bike lanes have also proven effective in delineating shared space.

Cyclist using a sharrow lane

Another tool coming to your toolkit soon is shared lane markings. Shared lane markings or “Sharrows” - short for shared-use arrows (see the picture above) are experimental pavement markings designed to remind motorists and bicyclists where bicyclists should generally ride when sharing a standard travel lane with other traffic. Bicyclists should ride over the center of the symbol in the same direction as traffic. Bicyclists and motorists must still follow the typical traffic rules and regulations; the markings simply serve as a reminder of the existing rules.

Sharrows are not intended to be a substitute for standard bike lanes. They may be a good option in situations where bike lanes are otherwise warranted but insufficient space is available. This marking is not included in the current edition of the National Manual on Uniform Traffic Control Devices (MUTCD), but the Federal Highway Administration (FHWA) has included the shared lane marking in a draft of a proposed new edition. In January 2007, the US National Committee on Uniform Traffic Control Devices (NCUTCD) endorsed the shared lane marking concept, and has recommended its inclusion in the National MUTCD. Until the shared lane marking is formally adopted as part of a new edition of the National MUTCD, use of this marking in the United States is still considered experimental, and is permitted only under experimental authorization issued by the FHWA.

Ithaca is one place where you will see these markings in use. According to Kent Johnson, Junior Traffic Engineer for the City of Ithaca, the city applied for and received permission to use this marking on an experimental basis. The benefit of the markings in other cities has been improved behavior on behalf of both bicyclists and motorists. The markings encourage bicyclists to ride further away from parked cars (outside of the “door zone”), to follow a more predictable path (reduced weaving around parked cars) and to ride with the flow of traffic (reduced wrong-way riding). For motorists, the markings increase their awareness that bicyclists may be present, leading to more careful passing of bicyclists. According to one study, the presence of the markings also led to a reduction of bicycle riding on sidewalks (a practice generally not recommended or permitted except for children or those with a disability). It is hoped that an evaluation of the treatment in Ithaca will document similar benefits.

For more information about bicycling in Ithaca, go to the city’s website and search for “bicycle information.”

Summer 2009

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This work by the Cornell Local Roads Program (CLRP) is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License.