In a region where transportation is high on the list of hot topics, discussion is particularly heated over high-occupancy vehicle lanes, otherwise known as HOV, carpool or diamond lanes (for the pavement symbols used to distinguish them from non-restricted lanes). The Metropolitan Transportation Commission (MTC) recently reduced the hours for HOV lanes on I-80 and recommended dropping HOV lanes on I-580 through Richmond. Balancing this are calls for adding HOV lanes to the gridlocked Sunol Grade on I-680 and on Hwy. 101 between San Carlos and San Francisco. As overall congestion on Bay Area highways increases, the role of HOV lanes is being re-evaluated to determine when they are an appropriate solution.
Controversial since their introduction in the 1970s, HOV lanes still give rise to emotional debates among Bay Area drivers. Goals for what HOV lanes will accomplish differ, with transportation planners, environmentalists, and weary commuters each looking at a different picture. Among those goals are congestion relief (fewer cars, faster speeds), pollution reduction, and reduced dependence on the automobile.
A 1997 report from the Bay Area Air Quality Management District (BAAQMD) fueled the debate with its conclusions that carpool lanes should be supported although they do not consistently reduce congestion and air pollution. Two other reports, one from the Orange County Transportation Authority and one by the University of California Transportation Center, have also indicated that unless certain conditions are in place, HOV lanes are not effective in reducing congestion. However, RIDES for Bay Area Commuters, Inc. reported in its recent Commute Profile 1999 that almost 25% of respondents with a carpool lane on their route to work used the lane regularly, and over 85% of users saved time by doing so.
The UC study showed that HOV lanes work better than mixed-flow lanes only when there is severe congestion and many high-occupancy vehicles are already using the route. Consistent with this, the greatest success with HOV lanes in the Bay Area has been on corridors such as Highway 101 northbound into San Jose, where in 1998 the carpool lane carried 42% of morning commuters. In Contra Costa, HOV lane use tripled on I-680 between 1994 and 1998.
On the theoretical level, HOV lanes should provide the incentive of fast, uncrowded lanes for people who carpool or take transit, speeding their trip and reducing air pollution by reducing the number of cars and the amount of stop-and-go traffic. Solo drivers should support HOV lanes because, in concept, when other solo drivers move into carpools or transit, the general use lanes will be less congested as well. In actuality, there are several factors involved, and any one can cause problems.
Speeding the trip and reducing air pollution work only if enough people, but not too many, choose to carpool, so that the number of vehicles on the road declines. If only a few carpools use the HOV lane, more drivers will be inconvenienced by congestion than would be the case if the HOV lane were given to general use. If new solo drivers replace those using HOV lanes, there will be no decrease in congestion in the general use lanes, or in the resulting air pollution. If the number of carpools approaches the capacity of the HOV lane, the result is increased congestion for everyone, and even the carpool lanes become slower, as has happened in Santa Clara County on Highway 237.
Therefore, the incentive is truly an incentive only if 1) HOV lanes are uncongested, 2) non-HOV lanes are unacceptably congested, and 3) it is more inconvenient to brave the congestion as a solo driver than to carpool or take transit. Staggered work hours (intended to reduce congestion), diverse work destinations and the actual or perceived need for a car during the workday all work against the carpool and transit options, while cost often works in their favor.
However, even if drivers are attracted to carpools or transit by other incentives, such as cost savings, HOV lanes may be the deciding factor. This is borne out by the RIDES report which shows that in heavily traveled corridors a significant number of commuters cite the availability of HOV lanes as a reason why they carpool, vanpool or ride transit, and say that without the lanes they would not continue to do so. Transit agencies also report increased ridership on lines which take advantage of HOV lanes to speed the trip, often matching or beating solo driving times.
The often-gridlocked Sunol Grade in Alameda County exemplifies the past, and the possible future, of the HOV issue. Early HOV lanes, including one in Alameda County, were converted from general use to HOV, and were discontinued after protests from displaced drivers. As a result, state law now prohibits changing a "mixed flow" lane to an HOV lane, meaning that new HOV lanes require new highway construction. In addition, legislation also banned new HOV lanes in unincorporated Alameda County. When transportation planners concluded that an HOV lane would be effective on the Sunol Grade, new legislation had to be passed.
Now there is debate on how to use the proposed new lane most efficiently, with some groups arguing that a carpool must be defined as three or more occupants, rather than the two people per car allowed at some locations in the region, because many commuters already try to cope with the Sunol Grade by doubling up, and switching them into the HOV lane would not improve congestion.
Another possibility is to create a high-occupancy/toll lane (HOT lane) which allows non-carpool drivers to pay a toll, varying by time of day, to use lanes otherwise restricted to high-occupancy vehicles. This has proven successful in Orange County, drawing vehicles from other lanes and reducing overall congestion. One problem with HOT lanes is that unless they were built as toll lanes, it may not be possible to convert them without encountering resistance from taxpayers who feel these lanes have been paid for with tax dollars and should be free.
HOT lanes are one compromise between those who feel that there should be no HOV lanes and those who feel that there are still good reasons for continuing to build a connected network of high-occupancy lanes throughout the region. Other options include reconsidering the number of occupants needed for a carpool and adjusting hours of restricted use. Another compromise has been suggested in the legislature, where bills were introduced during the last session to require regular monitoring and evaluation of HOV lane effectiveness, with ineffective lanes returned to general use. Since they cannot revert to HOV lanes once returned to general use, even if growing congestion warrants it, many planners are reluctant to advocate such a step.
As long as only newly constructed lanes can be HOV lanes, new construction plans will probably continue to include them, because it is the best way to ensure that they are available if they prove to be the most efficient alternative to congestion. Support will be there from transit operators and others who hope to reduce air pollution and fuel consumption. However, non-carpool drivers will still feel discriminated against unless the lanes are well-used. With roads and highways in the Bay Area projected as inadequate for the region's traffic even after proposed construction, the debate will continue.
Who Controls Bay Area HOV Lanes: The master plan for HOV lanes in the Bay Area is developed by the Metropolitan Transportation Commission (MTC) and was last updated in 1997. Caltrans and the county Congestion Management Agencies provide input. Information from the plan is incorporated into the Regional Transportation Plan. When HOV lanes are proposed as part of a specific project, MTC has legislative authority to approve them. Approval is done as part of the funding approval process.
An ad-hoc regional HOV lane committee, with representatives from MTC, Caltrans and the California Highway Patrol, tracks issues of efficiency and enforcement of HOV lanes and will make changes as appropriate. Caltrans also does extensive monitoring of all existing HOV lanes twice a year and produces an annual report. Based on ongoing Caltrans monitoring results of HOV lanes on I-580 in Richmond, the 1997 HOV Master Plan recommended eliminating them. State legislation does not give specific authority for elimination of HOV lanes, so the recent Commission recommendation has been sent to Caltrans for final action, which is expected by December 1999.
Leslie Stewart
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