HOV Lanes Exposed

Carpool lane facts for the San Francisco Bay Area

Updated 8/24/00

The bottom line:

Fewer people carpool today than before carpool lanes even existed.

Carpool lane construction increases solo-drivers more than HOVs, by more than twice as much.

The facts below, all from government data, contradict the "politically correct" facade of HOV lanes. This facade was created by highway construction interests, including Caltrans, to achieve their real goal: more highway construction.

The definition of carpool is a distortion of the concept:

Carpool lanes18 greatly increase solo drivers:

Carpool lanes increase air pollution:

Fewer people carpool today than before HOV lanes existed:

Carpool lanes are promoted by highway construction interests:

Increase in Vehicles resulting from adding HOV lanes, San Tomas Expressway (Santa Clara County).3 Vehicle counts in the peak commute direction were taken before and two years after increasing the lanes from 4 to 6. Data from Santa Clara County Transportation Agency. The increase in 2-Occupant does not mean a switch from solodriving as much as a switch from driving parallel roads to the less congested HOV lane, thus decreasing 2-Occupant on paralleling routes. When this figure was made, the definition of HOV nationally was at least three occupants.


Carpool lanes reduce mass transit usage, increase automobiles:

Solution for carpool lanes:

Three reasons why carpool lanes harm mass transit:

This page was compiled by Akos Szoboszlay, an engineer and President of the Modern Transit Society.
Articles by the Modern Transit Society:

Carpool lane facts

HOV lanes cause huge solo driver increase on Montague Expressway, Traffic engineers' disinformation on HOVs

HOV lanes cause huge solo driver increase on San Tomas Expressway and Rt. 237

Reallocate HOV lane construction funds

Casual carpooling reduces transit patronage, increases pollution

MTS rebuts RIDES claims

Bay Area Commuters data, 1980 & 1990 Censuses

Also see the Federal Transit Administration web site about HOV lanes:

Re-Thinking HOV - High Occupancy Vehicle Facilities and the Public Interest


1 Source: RIDES study quoted in Mercury News 1/24/99, p. 4B

2 Mercury News 1/24/99, p. 4B

3 HOV lanes cause huge solo driver increase on Montague Expressway; Traffic engineers' disinformation on HOVs:

HOV lanes cause huge solo driver increase on San Tomas Expressway and Rt. 237:

4 "Carpool Trivia" by Caltrans in Mercury News, 1/24/99, p. 1B.

5 Mercury News, 10/18/97, p. 1A, 22A.

6 Caltrans' unstated goal: moderntransit.org/ctc/ctc07.html#caltrans

7 Non-attainment of Clean Air Act at BAAQMD web site at http://sparc2.baaqmd.gov/sip/aboutsip.htm. Web page is called BAAQMD SIP.

8 RIDES report "How Bay Area Residents Commute," Table 5, on web site: http://www.rides.org/plan/pcmode.html

9 Much detail provided by the Free Market for Transportation Plan by the Modern Transit Society at moderntransit.org/fmt

10 Details in U.S. News&World Report, 2/8/99, p. 28

11 From a Rt. 237 questionnaire [Caltrans report dated March 1, 1989]

12 Employee Parking Cashout and Results of 10 studies

13 Rides report at http://www.rides.org/lv2corner/lv3ccrpt/cc3survey6.html
The report continues by clicking "next" or click "index."

14 Source: MTC Working Paper 5 from their web site, Table23.XLS. This is abridged on our website at
moderntransit.org/hov/ba-census.html. The original is at http://www.mtc.ca.gov/datamart/census.htm#WP (zipped, exel, win file).

15 "Demographics, Trends and Air Quality Working Paper" by SCCTA, dated Dec. 1990, page 37.

16 Letter from BAAQMD to MTC re: MTC's RTP, dated 9/30/98, page 1. From BAAQMD web site. File is mtclet.pdf

17 RIDES data on web page
The report continues by clicking "next" or click "index."

18 Carpool lanes are also called HOV lanes or diamond lanes. The original term is High Occupancy Vehicle [HOV] lanes.

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