High-occupancy vehicle lane

"HOV" redirects here. For other uses, see HOV (disambiguation).

A permanent, separated HOV lane on I-91 near Hartford, Connecticut

The HOV lanes in the Greater Toronto Area, including this one on Highway 404, are separated by a stripped buffer zone at most points. This buffer zone breaks occasionally to allow vehicles to enter and exit the HOV lane.

Highway bus lane(HOV-9) on Gyeongbu Expressway in South Korea

In transportation engineering and transportation planning, a high-occupancy vehicle lane (also called an HOV lane or carpool lane) is a lane reserved for vehicles with at least a specified number of occupants (described as "High Occupancy Vehicles", HOVs), often on specified days and times. These lanes are also known as carpool lanes, commuter lanes, restricted lanes, diamond lanes, express lanes, and are called transit lanes in Australia and New Zealand.

Implementation

Traffic sign used for high-occupancy traffic lanes in Norway.

Standard restrictive traffic sign in the United States. The lozenge symbol (◊) indicates a preferential-only lane restriction, in this case an HOV with two or more passengers

HOV lanes used on I-24 in Nashville omit solid line separation which typically divides the adjacent traffic flow. This setup allows the operator to leave when desired.

California's decal to identify clean air vehicles that are allowed to use HOVs regardless of the number of passengers.

The relative rarity of high-occupancy vehicles compared to single occupancy vehicles—estimated at 7%^{[citation needed]} of the traffic—in the United States and Canada makes HOV lanes work for the drivers who can use them. When it is uncongested, an HOV lane can move at full speed even when parallel non-HOV lanes are congested. An HOV lane can move more people per lane, usually at a higher speed, with fewer vehicles than with single occupancy. In some communities, including Atlanta, Houston, Los Angeles, Washington, D.C., and Seattle, HOV lanes regularly carry more people than adjacent lanes, as reported by the Transportation Research Board HOV Committee.

Various organizations and services make it easier for commuters to utilize HOV lanes. Regional and corporate sponsored vanpools, carpools, and rideshare communities give commuters a way to increase occupancy. For places without such services, online rideshare communities can serve similar purpose.

Enforcement and penalties

The HOV lane system is made possible by penalties, usually fines, imposed for use of the lanes by vehicles with fewer occupants than specified.

Qualified vehicles

Qualification for HOV status varies by locality, for instance, the minimum number of occupants may vary. When an automobile is used as an HOV, the group of people using it is often called a carpool. The term HOV may include other types of vehicle than cars. An HOV may be allowed to travel on special road lanes, usually denoted with a diamond marking in the United States and Canada, on which vehicles not meeting minimum occupancy are prohibited, called restricted lanes, carpool lanes or diamond lanes. In some cases certain single-occupant vehicles such as hybrid vehicles or those using native fuels may be driven. U.S. federal law, binding all states, requires that HOV lanes "must allow motorcycles and bicycles to use the HOV facility, unless either or both create a safety hazard." In Canada there are no such exemptions. Some lanes in various areas are permanently restricted to HOV traffic, others are restricted only at specified times, usually peak traffic times.

In some regions buses are allowed to travel on the road shoulder when traffic becomes heavy, but it is often illegal for cars to take the shoulder to get around traffic jams. Some road shoulders are designed to act both as bus and accident lanes.

In exceptional situations an HOV "cordon" is sometimes placed prohibiting all vehicles from crossing the cordon during specified times. The cordon is enforced through the use of police checkpoints. For example, Midtown and Lower Manhattan were placed under cordons during the morning peak hours in the aftermath of the September 11, 2001 attacks and during the 2005 New York City transit strike.

Reversible lanes

Main article: Reversible lane

Some cities that use separated HOV lanes make them reversible; i.e. usable only by inbound traffic during the morning rush and usable only by outbound traffic during the evening rush. This method met with criticism after a negligent highway employee failed to close the gate preventing access to the HOV lanes of Interstate 279 in Pittsburgh, Pennsylvania in August 1995, causing a high-speed head-on collision that killed six people.

Separate systems

Some HOV lanes are built on completely separate roadways from their corresponding general use lanes, some are constructed on parallel roads separated by a concrete barrier, and others are built on grade-separated (i.e. elevated or underground) roadways. One example is the Harbor Freeway in Los Angeles, California, where four HOV lanes travel on the upper deck of the freeway. This type of construction is said to maintain optimal efficiency by keeping traffic from merging back and forth into the HOV lanes, and by maximizing space on the main roadway for non-HOV traffic.^{[citation needed]} Additionally, major interchanges on such routes are often equipped with HOV-only ramps, which minimizes haphazard cross-freeway merging.hours and weekends.

HOV-only highway

An extreme example is Interstate 66 in the Northern Virginia suburbs of Washington, D.C. During rush hour, on a 10-mile (16 km) segment of I-66 between the Capital Beltway and the Theodore Roosevelt Bridge (Virginia state line/Washington city limit), the entire roadway in the direction of rush-hour traffic (eastbound in the morning, westbound in the evening) is reserved for HOVs.

Priority

Many cities use HOV lanes to allow carpool traffic to bypass areas of regular congestion. For example, in Metro Vancouver, British Columbia, HOV traffic is separated from general traffic and given priority access to the entrance to George Massey Tunnel.

Criticism

Safety

The traffic speed differential between HOV and general purpose lanes creates a potentially dangerous situation if the HOV lanes are not separated by a barrier. (A Texas Transportation Institute study found that HOV lanes lacking barrier separations caused a 50% increase in injury crashes.)

Rights

USA

The National Motorists Association in the U.S. opposes HOV lanes on the grounds that motorists are entitled to full use of highway systems paid for by their taxes.

Netherlands

In the Netherlands, the first HOV lane in Europe was opened on the A1 on 27 October 1993. On the first day an unaccompanied driver (a former government minister) drove on the lane to cause a legal test case. The judge ruled that Dutch traffic law lacked the concept of a "car pool" and thus that the principle of equality was violated. At the end of the following year, the lane was opened to all traffic as a reversible lane.

Effectiveness

Arguments from other motorist advocacy groups put forth the argument that the best gains to be made in reducing high-density traffic is when all lanes are available for all vehicles, thus allowing a maximum of traffic to filter forward during peak travel times.

However some evidence from the operation of urban arterials in Brisbane, Australia shows that a properly enforced HOV lane, operating as designed, can increase person throughput. In 2009 and 2010 traffic surveys showed that in Brisbane on a number of urban arterials with Bus and Transit lanes non-compliance rates were approaching 90 per cent. Following enhanced enforcement of the lanes, non-compliance rates dropped and overall efficiency of the Bus and Transit lanes improved with an up to 12 per cent increase in total person throughput in the lane. Average bus journeys times dropped, in some cases, by up to 19 per cent.

Under-utilization

Critics have argued that HOV lanes are underutilized. It is unclear whether HOV lanes are sufficiently utilized to compensate for delays in the other mixed-use lanes.

Criticism has resulted^{[citation needed]} in many HOV lane restrictions being removed, for example in the US cities of Orlando, Santa Monica and New Jersey.

Possible future directions

A number of cities are considering converting under-utilized HOV lanes to high-occupancy toll (HOT) lanes, and others intend to build infrastructure supporting such lanes. This would permit single-occupant vehicles to use the HOV lanes on payment of a toll, but total flow would be regulated with automatically determined variable pricing based on demand, to ensure total speeds on the HOV lane do not drop noticeably.

In August 2010 the Utah Department of Transportation implemented such a program for traffic along Interstate 15 from Layton in the north to Lehi in the south. The system uses RFID transmitters to monitor entry and exiting of the lane and charges drivers between 25 US cents to one dollar, depending on demand. The transmitters can be turned off in vehicles carrying more than one occupant.

User phenomena

One symptom of HOV lanes that challenges the contention that HOV lanes are not effective has been the slugging phenomenon in the Northern Virginia suburbs of Washington, D.C. Slugging is the term used to describe a unique form of commuting where drivers go to pre-arranged "slug lines" and pick up commuters who need a ride. The driver shouts out his destination, and people in the line going to that destination enter the car on a first-come-first-served basis. There is very specific etiquette to the system to ensure a fair, consistent, and agreeable commute for all. Slugging benefits drivers by enabling them to use the HOV lane, benefits "sluggers" by getting them free rides, and benefits the community by decreasing the number of cars on the road.

In San Francisco and surrounding communities, designated casual carpool sites allow drivers to pick up passengers to the same destination.

When HOV lanes were first introduced in California in the 1970s, some drivers placed an inflatable person in the passenger seat in an attempt to fool regulators. This was soon outlawed, but the practice persists. In the UK in 2005, a camera that was claimed to distinguish mannequins or dolls from humans was being tested on the Forth Road Bridge in an effort to thwart cheaters.

See also

• Bus lane
• Bus rapid transit
• High-occupancy toll (HOT)
• List of HOT and ETL lanes in the United States
• Local-express lanes, another form of lane separation for congestion mitigation
• Public transit
• Toll road
• Transit lanes, the Australian equivalent to high-occupancy vehicle lanes
• Transportation Demand Management

External links

• History of Carpooling in California by Joseph Bishop founder TrafficBulldog.org
• UrbanTransport.org discussion of HOV lanes