Freeway Management Program
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Frequently Asked HOV Questions

We get many questions regarding HOV systems. Answers to these frequently asked questions (FAQs) are provided below. Click on a question to go directly to the answer. As concerns and interests evolve, these questions may be changed and updated.

  1. What is an HOV lane?
  2. How do they work?
  3. I drive alone to work. Why should I support HOV lanes when I can't use them?
  4. Where would I find out about ridesharing opportunities in my area?
  5. Are there other types of HOV facilities, besides carpool lanes?
  6. What does an HOV lane look like?
  7. How many HOV lanes are there in the U.S.?
  8. Is it legal to restrict publicly-funded highway lanes to HOVs?
  9. Who is responsible for building and operating HOV lanes?
  10. How are HOV lanes enforced?
  11. What happens to drivers who violate HOV lane rules?
  12. Why do some HOV lanes allow a minimum of two passengers per vehicle, while others require three?
  13. Do children and infants count as passengers?
  14. Why do HOV lanes often appear empty?
  15. Why are motorcycles allowed in some HOV lanes?
  16. What about two-seater vehicles? Are they allowed to use HOV lanes with three-person requirements?
  17. Are other vehicles prohibited from using HOV lanes, even with the appropriate number of passengers?
  18. What is the safety record of HOV lanes?
  19. Do HOV lanes operate only during rush hours?
  20. Are HOV lanes effective?
  21. What are some of the measures of effectiveness?
  22. Can HOV lanes be put to other uses as well?
  23. Some say that HOV lanes aren't as good for air quality as they were originally thought to be. Is that true?
  24. There are some areas with more than one HOV lane. Are these facilities coordinated with one another?
  25. How can I learn more about HOV facilities?

Answers to FAQs About High Occupancy Vehicle (HOV) Facilities

  1. What is an HOV lane?
    An HOV lane, sometimes called a carpool lane, is a special lane reserved for the use of carpools, vanpools and buses. They are usually located next to the regular, or unrestricted, lanes. These special lanes enable those who carpool or ride the bus to bypass the traffic in the adjacent, unrestricted ("general purpose") lanes. Lanes are identified as "2+" or "3+" which refers to the minimum number of occupants to qualify.
  2. How do they work?
    HOV lanes are intended to incentivize throughput (move more persons per car, per lane) and save time for car-poolers and bus riders by enabling them to bypass the areas of heaviest traffic congestion. Because most drivers, especially during rush hours, are driving alone, the HOV lane is seldom congested. Giving car-poolers a reliable and congestion-free ride during rush hour serves as a strong incentive for ridesharing HOV lanes also provide commuters a needed alternative to congestion, which is not always possible if all lanes are opened to everybody.
  3. I drive alone to work. Why should I support HOV lanes when I can't use them?
    HOV lanes benefit not only those who share the ride, but all drivers, taxpayers and area residents. First, by encouraging high-occupancy travel (that is, more passengers in fewer vehicles) these lanes can help ease congestion in heavily-traveled metropolitan areas. Second, by reducing the traffic burden on highways, they can help defer costly expansion projects. Third, by reducing the number of vehicles on the road, HOV lanes can help reduce the extent of exhaust emissions and contribute to cleaner air.
  4. Where would I find out about ridesharing opportunities in my area?
    Most state Departments of Transportation and local agencies sponsor programs to support ridesharing. These programs include ride matching databases to help commuters find carpool partners; coordination of employer ridesharing programs; vanpooling programs, and up-to-date information on transit alternatives throughout the area. Contact your state Department of Transportation to learn about its ridesharing program.
  5. Are there other types of HOV facilities, besides carpool lanes?
    While the most common type of HOV facility is a carpool lane, other types of HOV facilities include exclusive HOV ramps, bypass ramps at ramp meters, toll plazas and ferry docks, bus lanes and commuter parking lots with direct connections to HOV lanes.
  6. What does an HOV lane look like?
    For the most part, HOV lanes look like any other street or highway lane, except that it is typically delineated with signs and diamonds painted on the pavement. But there is a great deal of variety in the design and operation of HOV lanes. Some, called concurrent flow lanes, lie adjacent to, and operate in the same direction as general purpose lanes. Others, called contraflow lanes, operate in the opposite direction of adjacent lanes, enabling HOVs to drive on the "wrong" side of the highway with barriers separating them from oncoming traffic. Reversible lanes, usually placed in the highway median, run in one direction in the morning, then in the opposite direction in the afternoon. Busways are usually physically separated from adjacent lanes, and are reserved for bus use only. HOV lanes are delineated by several methods, including barriers, medians rumble strips, buffer areas, and pavement markings.
  7. How many HOV lanes are there in the U.S.?
    It is getting harder and harder to quantify this as new facilities and some older ones advance to include HOV service as part of a larger project. The new lexicon cites "managed lanes", which at the broadest definition could refer to any dedicated or restricted lane that is not purely general purpose. However, the colloquial use refers to that subcategory of highway lanes that are managed via price control (HOT, tolling, etc.) or vehicle exemption (HOV, truck-only tolls, bus-only, etc.) and are often managed dynamically, i.e., by varying price or restrictions in response to demand or time of day. The last strictly HOV inventory was published in December 2008 in FHWA's A Review of HOV Lane Performance and Policy Options in the United States. That document identified 345 facilities; 301 were open at the time, 14 were under construction, 10 were still being actively planned, 15 were still under environmental and preliminary design review, and five were constructed but still inactive at the time of the study. However, that study did not report aggregated lane mileage. The 2012 Priced Managed Lane Guide states that "as of May 2012 there are 14 operating priced managed lane facilities nationwide (the colloquial definition) with an additional 14 under construction and 25 others in planning." An HOV element exists in most of that list. That guide sums up the HOV experience thusly; "today, HOV lanes remain the most prevalent form of managed lane (the broad definition) in the United States, with lane-miles in service doubling from 1,500 in 1995 to over 3,000 in 2005." (That number has since been re-estimated at 3,300 miles in 2010.)
  8. Is it legal to restrict publicly-funded highway lanes to HOVs?
    Most state Departments of Transportation have the legal authority to regulate use of the highways, as long as the rules are applied fairly and serve a public benefit. Also, federal legislation – the Clean Air Act Amendments of 1990 and the Intermodal Surface Transportation Efficiency Act of 1991 – specifically encourage states to consider, and implement, if feasible, HOV lanes in areas experiencing air quality or traffic congestion problems.
  9. Who is responsible for building and operating HOV lanes?
    Public agencies, such as State Departments of Transportation and transit agencies, construct and operate HOV lanes, often with federal funding support. Some municipal transportation agencies have built HOV facilities on local roadways, and in California, a private company has built a toll road on State Route 91 which serves carpools.
  10. How are HOV lanes enforced?
    All HOV projects rely on state or local police officers to monitor and enforce HOV lane requirements. In Washington State, a "HERO" program adds an element of self-enforcement, by encouraging commuters to report HOV lane violators to the State Police.
  11. What happens to drivers who violate HOV lane rules?
    Violators can be stopped and cited by the enforcement officer monitoring the HOV lane, or simply re-directed back into the slower-moving general purpose lanes. Fines accompanying the citation vary from state to state, from $50 in Massachusetts to over $300 in California depending on the number of citations offenders have received.
  12. Why do some HOV lanes allow a minimum of two passengers per vehicle, while others require a minimum of three?
    Entry requirements are set according to local travel conditions, levels of existing congestion, and projected use of the lane. If there are a high number of existing two-person carpools, then letting them all in might cause congestion in the HOV lane. If there are not enough three-person carpools and buses, then the lane might be perceived by the public as "empty." In all cases, entry requirements are designed to allow for high speed travel, without allowing the lane to become perceived by the public as underutilized or congested. The balancing of these objectives can be difficult. Some states, in an effort to achieve this balance, have experimented with entry rules, changing them by time of day or raising or lowering the number of vehicles that can use the facility.
  13. Do children and infants count as passengers?
    Yes. All states with HOV facilities count children and infants as passengers.
  14. Why do HOV lanes often appear empty?
    HOV lanes, designed to be free of congestion, sometimes have the appearance of being lightly traveled, especially when compared with adjacent, congested unrestricted lanes. When the number of people traveling in an HOV lane is compared, though, HOV lanes are typically busier than unrestricted lanes. HOV lanes carry more people than unrestricted lanes, making them highly efficient as well as beneficial to air quality.
  15. Why are motorcycles allowed in some HOV lanes?
    Motorcycles are permitted by federal law to use HOV lanes, even with only one passenger. The rationale behind allowing motorcycles to use HOV lanes is that it is safer to keep two-wheeled vehicles moving than to have them travel in start-and-stop traffic conditions. States can choose to override this provision of federal law, if they determine that safety is at risk.
  16. What about two-seater vehicles? Are they allowed to use HOV lanes with three-person requirements?
    Usually not, although in isolated cases two-seater vehicles are permitted. Most states wish to maintain a consistent approach to enforcing entry requirements, and do not allow exceptions to entry rules. The entry rule is based not on how full the car is, but on how many passengers are in it.
  17. Are other vehicles prohibited from using HOV lanes, even with the appropriate number of passengers?
    Yes. Many states prohibit oversized vehicles, such as tractor-trailer trucks, for safety reasons. For the same reasons, parades, processions and certain types of heavy trucks and large recreational vehicles are sometimes precluded from using HOV lanes.
  18. What is the safety record of HOV lanes?
    HOV lanes have existed going on four decades now. Safety and operational analyses have improved upon the design, operation, and enforcement with each iteration of HOV advancement, including to retrofit the earliest designs, and to exhaustively critique the newer "managed lanes" that may include tolled vehicles and/or "intelligent" operation. Studies have shown that HOV lanes are frequently as safe as, and in many cases safer than, unrestricted lanes. The safest HOV lanes are those that are physically separated from the adjacent lanes with a concrete barrier, but that would be the case for general purpose lanes too.
  19. Do HOV lanes operate only during rush hours?
    Operating hours vary from state to state. Some states operate their HOV lanes only during rush hours, when traffic is heaviest and HOV lanes are most likely to save time for car-poolers. During off-peak hours, these states either open the lanes to all traffic or simply close them until the next scheduled opening. Other states operate their HOV facilities around the clock. This approach helps to provide ridesharing incentives at all times, and provides travel time savings during times of unexpected congestion, for example, during special events or when there is an incident or accident.
  20. Are HOV lanes effective?
    Yes, though results vary from state to state. Nearly every state with HOV lanes reports that ridesharing and overall corridor person moving efficiency has increased since the lanes opened.
  21. What are some of the measures of effectiveness?
    Evaluating HOV lanes is in some ways similar to evaluating other highway facilities – safety, vehicle volumes, and level of service are generally evaluated on both types of facilities. HOV evaluations also examine impacts on person movement (how many people, as opposed to how many vehicles, use the lane) modal shifts (how many people changed their travel behavior to take advantage of the HOV lane), and travel time savings are all important indicators of HOV lane performance.
  22. Can HOV lanes be put to other uses as well?
    Yes. Some states open carpool lanes to all traffic when the rush hour is over. Others temporarily open the lanes to all traffic during rush hours if there is a major accident, causing much more severe congestion than usual of the highway. Some locales are considering allowing trucks to use the lanes during off-peak hours.
  23. Some say that HOV lanes aren't as good for air quality as they were originally thought to be. Is that true?
    Several studies have been conducted on this topic, and while conclusions vary as to how much HOV lanes contribute to cleaner air, none dispute that their impact on air quality is positive.
  24. There are some areas with more than one HOV lane. Are these facilities coordinated with one another?
    Yes. Many states and regions develop HOV "systems plans" to ensure that they are prepared to meet future HOV needs while coordinating the development of existing facilities. Washington State, California, Nashville and Texas all have conducted system planning to coordinate area-wide HOV facilities.
  25. How can I learn more about HOV facilities?
    The HOV Facilities page of this web site and the HOV Pooled Fund Study web site provide more information on HOV facilities.
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