Shared lane marking

Picture of chevron–style shared lane marking in Toronto, Canada. This sharrow is improperly placed too far right, and the cyclist is riding unsafely in the Door Zone.

A shared-lane marking or sharrow^[1] is a street marking installed at locations in Australia, Canada, and the United States. This marking is placed in the center of a travel lane to indicate that a bicyclist may use the full lane.

According to the US Manual on Uniform Traffic Control Devices, shared-lane markings are used to:

• Assist bicyclists with lateral positioning in a shared lane with on-street parallel parking in order to reduce the chance of a bicyclist’s impacting the open door of a parked vehicle;
• Assist bicyclists with lateral positioning in lanes that are too narrow for a motor vehicle and a bicycle to travel side by side within the same traffic lane;
• Alert motorists of the lateral location bicyclists are likely to occupy within the traveled way;
• Encourage safe passing of bicyclists by motorists; and
• Reduce the incidence of wrong-way bicycling.^[2]

The name sharrow was coined by Oliver Gajda, of the City and County of San Francisco Bicycle Program, and is a portmanteau of share and arrow.^[3]

History

These markings are used in the USA, Australia and other countries. In US usage, the wide shape of the arrow, combined with the bike symbol, gave rise to unofficial names such as "bike in a house" or "sharrow". In the UK roughly the same function is served by a bicycle symbol without arrows. However this tends to be used more as an indication of a formal cycle route rather than as an encouragment to share the road.

The original "bike in a house" or "man jumping barrels at home" marking was developed by James Mackay and included in the 1993 Denver Bicycle Master Plan.^[4] While Mackay had considered a "connect the dots" pavement markings approach for bicycle route definition and lane positioning reinforcement for bicyclists earlier when he was the Bicycle Facilities Engineer for the North Carolina Department of Transportation, the City of Denver's unwillingness to commit to bike lane markings meant that shared lane markings were the only pavement marking treatment for bicyclists that the City would implement. The hollow arrow surrounding the bicyclist was intended to reinforce the correct direction of travel for bicyclists (who were frequently observed riding the wrong-way, against traffic, in Denver).^[5]

In 2004, the city of San Francisco, California began experimenting with the shared lane marking,^[6] and developed a revised symbol consisting of a bicycle symbol with two chevron markings above the bicycle.

In a 2009 paper,^[7] Northeastern University researcher Peter G. Furth proposed the "Bicycle Priority Lane", which combines sharrows with dotted lines inside the usual lane markings. This marks a five-foot-wide zone in the center of the lane which bicyclists are encouraged to use. The city of Boston, Massachusetts began experimenting with these markings in 2013.^[8]

Effectiveness

Behavioral studies have shown that streets with shared lane arrows increase separation between motor vehicles and bicyclists, encourage cyclists to ride outside the door zone, and may reduce wrong-way cycling and sidewalk cycling, which are associated with increased crash risk.^[9][10]

However, another study based on hospital records shows no statistically significant reduction in injuries, and possibly a small increase.^[11]

Usage

United States

Shared-lane markings alternating with full bike lanes in Grand Street (Manhattan).

Based on the San Francisco experimental data, in August 2004 the California Traffic Control Devices Committee (CTCDC) approved the use of this marking in the State of California.^[12]

In the 2009 edition of the Manual on Uniform Traffic Control Devices, shared lane markings were approved for general use.^[13]

Some US jurisdictions installed this marking before they were officially adopted without participating in US federally approved experiments. There is a concern that the shared lane markings installed in some of these locations are not consistent with current regulations on marking design and positioning.

The city of Seattle, Washington included extensive use of shared lane markings in its Bicycle Master Plan of early 2007.^[14]

Sharrows have been used in a number of U.S. cities, including:^[15]

Canada

• Edmonton has begun to install shared-lane markings on several streets in 2009 .^{[citation needed]}
• Hamilton began installing sharrows in 2010
• Moncton has begun using shared-lane markings in 2010 .^{[citation needed]}
• Montreal has had shared-lane markings on paths into and out of the downtown core, since 2006.^[41] Many indicate a path of travel inconsistent with the intent of the shared-lane marking.^[42][43]
• Saskatoon installed shared-lane markings on most of its downtown streets in 2009 .^{[citation needed]}
• St. Catharines (Ontario) has upgraded several major streets (Scott Street, Geneva Street) and the downtown core with sharrows as of 2009 .^{[citation needed]}
• Toronto (Ontario) also features "sharrows" on several streets .^{[citation needed]}
• Vancouver has sharrows on some streets, in addition to separated bike lanes.^[44]
• Victoria, BC — In July 2009, "activist" cyclists calling themselves the Other Urban Repair Squad twice painted markings on congested Hillside Avenue but the City of Victoria immediately dispatched crews to cover the markings with gray paint.^[45][46]
• Winnipeg has begun to use shared-lane markings since 2008 Template:Citation neededes.
• Fredericton has begun to use shared-lane markings since 2012 .^{[citation needed]}
• Kitchener has begun to use shared-lane markings as of May 2013 ^{[citation needed]}

Spain

• Murcia began installing sharrows in 2009.^[47]

Australia

• Adelaide, South Australia
• Melbourne, Victoria

See also

• Shared space

References

External links

Wikimedia Commons has media related to Sharrows.

• "Four Solid Uses for Sharrows"
• NCUTCD webpage on shared-lane marking
• FAQ on shared lane markings created by Bike Pittsburgh and the Pittsburgh Dept. of City Planning