Freeway Management Program
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Freeway Management Program > Managed Lanes and HOV Facilities > HOV Facilities

Frequently Asked HOV Questions

The Office of Operations gets many questions regarding high-occupancy vehicle (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 HOV lanes 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 other vehicles are allowed on HOV lanes?
  19. What is the safety record of HOV lanes?
  20. Do HOV lanes operate only during rush hours?
  21. Are HOV lanes effective?
  22. What are some of the measures of effectiveness?
  23. Can HOV lanes be put to other uses as well?
  24. Some say that HOV lanes aren't as good for air quality as they were originally thought to be. Is that true?
  25. There are some areas with more than one HOV lane. Are these facilities coordinated with one another?
  26. 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 required in a vehicle to use the HOV lane.
  2. How do HOV lanes work?
    HOV lanes are intended to incentivize throughput (move more persons per car, per lane) and save time for carpoolers and bus riders by enabling them to bypass congestion in the regular, or “general purpose” lanes. HOV lanes offer carpoolers a reliable and congestion‑free ride during rush hour to serve as a strong incentive for ridesharing. HOV lanes also provide (primarily peak hour) commuters a needed alternative to congestion, which is not always possible if all lanes are opened to everybody. A congested HOV lane undermines the integrity of a reliable trip for carpoolers, therefore it is paramount to preserve the purpose of HOV lanes.
  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. High-occupancy travel (that is, more passengers in fewer vehicles) helps ease congestion in heavily traveled metropolitan areas by reducing the number of single-occupant cars. Second, reducing the traffic burden on highways helps 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. Expanding HOV lanes to High Occupancy Toll (HOT) lanes allows drivers who are willing to pay a toll to accrue the HOV benefits of time saved and less congestion.
  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, up-to-date information on transit alternatives throughout the area, and general rules for HOV lane usage. Contact your State Department of Transportation (e.g., via their website) to learn about ridesharing programs in your area.
  5. Are there other types of HOV facilities, besides carpool lanes?
    While the most common type of HOV facility is a carpool lane, here are some other types of HOV facilities: 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.

    Two other similar facilities are High Occupancy Toll (HOT) lanes and Express Toll Lanes (ETL).

    An HOT lane is fundamentally an HOV lane by preserving the HOV-free concept, while also permitting non-qualifying HOVs to use it, such as toll paying single-occupant vehicles (SOVs) or qualifying energy-efficient vehicles, like electrics, that display a permissible decal or license plate. The public authority that oversees the facility can allow these extra vehicles only if the HOV lane has sufficient capacity and maintains a legislatively mandated minimum speed. If these exempted vehicles overburden the HOV lane causing speeds to decline below the threshold, they may be managed or removed to preserve the integrity of the HOV’s purpose (e.g., carpooling). For more information on HOT lanes, please visit the Office of Operations website “HOT Lanes, Cool Facts” at  https://ops.fhwa.dot.gov/publications/fhwahop12031/fhwahop12027/index.htm.

    An ETL, or commonly, “Express Lane,” is a third type of facility. Like an HOV lane or HOT lane, an ETL typically runs parallel to, and within the same right-of-way as, the general-purpose highway, but an ETL typically charges all vehicles a toll regardless of vehicle occupancy. An ETL operator may permit qualifying HOVs a discounted or free trip, but that is at the discretion of the operator and the regional transportation oversight.

  6. What does an HOV lane look like?
    HOV lanes often look like any other street or highway lane, except that they are typically delineated with signs and diamonds painted on the pavement. Most of the differences are in the operation of HOV lanes. Some, called concurrent flow lanes, are 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.?
    As of July 2023, there are 105 HOV facilities in 19 states. Also, there are 37 HOT facilities in 10 states. The full list, by state, can be found on FHWA-HOP-24-018 which can be found at https://ops.fhwa.dot.gov/freewaymgmt/mngd_lns_hov.htm.
  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—e.g., 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. Motorists always have the availability of the free adjacent general-purpose (GP) lanes; that is to say, HOV lanes complement, and don’t usurp, GP lanes for the same trip.
  9. Who is responsible for building and operating HOV lanes?
    Primarily public agencies, such as State Departments of Transportation and regional transit agencies, construct and operate HOV lanes, often with federal funding support. However, there are several instances of cooperative public-private partnerships (PPPs) which help reduce the States’ financial burden in return for some private equity and toll revenue for the participating private company.
  10. How are HOV lanes enforced?
    All HOV projects rely on state or local police officers to monitor and enforce HOV lane requirements. Vehicle occupancy enforcement is largely done by side-of-the-road observation, but increasingly by camera detection. There is ongoing research to develop in-car apps or similar that would allow motorists to “self-comply,” thereby, effecting enforcement by compliance rather than reliance on punitive measures. (See item 11 also.)
  11. What happens to drivers who violate HOV lane rules?
    Many HOV/HOT lanes are enforced via police stops; the motorist will get a citation then and there. Other HOT lanes are electronically enforced (e.g., overhead or roadside camera); the agency will mail a ticket to the registered vehicle owner. Fines accompanying the citation vary from State to State, depending on the States’ laws and the number of citations offenders have received. However, as noted above in the answer to question 10, a strong push exists to develop enforcement not solely as a punitive measure, but rather to enable “compliance” to promote rewards for using an HOV lane, and to reduce the burden on law enforcement and follow-up adjudication. An example of how this might be accomplished is that a motorist might use his or her smartphone app to “declare” vehicle occupancy compliance and receive a credit against their toll account. Of course, police will continue enforcement-of-compliance too.
  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 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 a generally congestion free, reliable trip, without allowing the lane to become perceived by the public as underutilized or congested. The balancing of these objectives can be difficult. Some States, 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. Pregnant individuals are counted as one seat-occupant.
  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 via a “shall” condition to use HOV lanes, primarily because they do not/cannot carry more than one person. While there are some 2- and 3-wheeled vehicles that may meet “motorcycle” definitions, consideration of these vehicles as motorcycles for the purpose of HOV lane usage depends on the State. 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 congested traffic conditions on the general-purpose lanes. States can choose to override this (explanation is in the provision of federal law under U.S.C. Title 23 Section 166(b)(2)) 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, e.g., as in question 15 above, it depends on the States’ own definition of motorcycles. But generally speaking, two persons in a two-seater coupe would not be exempted on a 3+ facility. Most States wish to maintain a consistent approach to enforcing entry requirements and do not allow exceptions to entry rules.
  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-trailers, or maybe tow-and-hitch vehicles, 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. It’s best to pre-check with your State’s permissions.
  18. What other vehicles are allowed on HOV lanes?
    Federal law, not State laws, stipulates permissions. Motorcycles and on-duty blood transport vehicles have shall permissions. Public transportation vehicles, over-the-road buses serving the public, certain qualifying low emission and energy-efficient vehicles, and single occupant vehicles paying a toll —which makes the HOV lane a HOT lane – are may permissions. All of these may be found in U.S.C. Title 23 Section 166.
  19. What is the safety record of HOV lanes?
    HOV lanes have existed for nearly 5 decades. 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. For example, in single-lane HOV facilities, the “escalator” principle applies; that is, everyone (every ‘car’) is essentially going the same speed in single-file, with no passing or lane-changing, i.e., movements that would otherwise increase safety risk. HOV lanes are like regular lanes; they have the same pavement,  lane widths and speed limits. The safest HOV lanes are those that are physically separated from the adjacent lanes with a concrete barrier or median, but that would be the case for general purpose lanes too.
  20. Do HOV lanes operate only during rush hours?
    Operating hours vary from State to State and even from facility to facility in some States. The hours are always posted. Some States operate their HOV lanes only during rush hours when traffic is heaviest and HOV lanes are most likely to save time for carpoolers. 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 crash. States have autonomy to open the HOV lanes during rare extreme events or under special circumstances (e.g., a shutdown on the mainline). Usually, these facility operators have internal guidelines and thresholds developed in advance.
  21. 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. And carpooling is inherently beneficial to air quality.
  22. What are some of the measures of effectiveness?
    Evaluating HOV lanes is similar to evaluating other highway facilities; e.g., safety, vehicle volumes, and level of service are generally evaluated on all types of facilities. But 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, which are all important indicators of HOV lane performance. Because HOT lanes permit other-than HOVs, they are uniquely mandated to complete annual certifications that the lanes are operating “sufficiently” (i.e., congestion free) to maintain the HOV integrity thereon. If those other vehicle permissions were to slow the lane to below the criteria, then they may have to be mitigated or removed.  HOV-only facilities do not face the same mandate, but are otherwise managed to maintain sufficiency, for a clogged and congested HOV facility would be averse to the purpose of HOV lanes.
  23. 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 when a major crash or event might cause much more severe congestion than usual on the highway. Some locales are considering allowing trucks to use the lanes during off-peak hours. The facility operator, in conjunction with the police, typically determines when HOV lanes should be opened to other traffic. Currently there are no Federal mandates concerning when or how to manage HOV lane purpose for other than ‘carpoolers’; these decisions are at the facility-operator level, but often in consultation at least with the respective FHWA Division office.
  24. 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, no studies dispute that HOV lanes positively impact air quality. Over the years the auto industry has improved emissions on their own merits. For example, an electric car is emission free whether in a HOV lane or a GP lane. But the basic premise is that more persons traveling in fewer vehicles, presuming at-speed and not idling in congestion, is much better than the inverse.
  25. There are some areas with more than one HOV lane. Are these facilities coordinated with one another?
    Often, 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, for example, have conducted system planning to coordinate area wide HOV facilities.
  26. How can I learn more about HOV facilities?
    The HOV Facilities page of this website and the HOV Pooled Fund Study website provide more information on HOV facilities.