Car-Pool Lanes
Your editorial (Jan. 15) welcomed the opening of the new car-pool lane on the San Diego Freeway as a “realistic and workable alternative.” Recently established facts prove otherwise. The loss due to vehicular underutilization of the lane far exceeds the gain due to additional motivated car pools.
In order to maintain the car-pooling incentive, a car-pool lane must, does and always will carry significantly less vehicle traffic than a mixed-flow lane. The loss of vehicle capacity, which is so obvious to the casual observer, is rather easy to evaluate by traffic counts. Over the congested period of the day the Costa Mesa car-pool lane is currently carrying about 47%, a little less than half of the traffic of the adjacent mixed-flow lanes. In other words, what we really have is a 3.47-lane freeway rather than the four-lane freeway we would have if the car-pool lane were converted to mixed flow. This represents a real loss of 14% vehicle capacity for the freeway as a whole.
Thus the car-pool lane could be a winner in terms of net person carrying capacity if and only if it were to motivate a 14% or greater increase in the average number of occupants per vehicle (Average Vehicle Occupancy or AVO) for the freeway as a whole.
In fact, however, the car-pool lane motivated increase in the average number of occupants is far less than the break-even amount, 2% at most. This is based on the only three existing independent determinations of this quantity, two of which (2.0% and 1.3%) are by our organization on different databases, and the third (0.7%) by (former UCI researcher) Genevieve Giuliano of the UCI Institute for Transportation Studies and USC (LA Times, Dec. 7). Thus the Costa Mesa Freeway is a net loser by a huge margin of at least 7 to 1. Furthermore, to the best of our reasonably well-informed knowledge, there has never been a showing of a car-pool lane locally or nationally that has ever proven to be a net winner in this sense.
Evaluated on a net-benefit basis, the car-pool lane is counterproductive to its expressed aims and enormously costly to the Orange County economy and environment. At the same person-carrying load, for example, the net loss of approximately half of a freeway lane of person-carrying capacity due to the car-pool lane on the 11-mile Costa Mesa Freeway is directly responsible for unnecessary congestion costing about $274,000 in lost man-hours, 44,000 gallons of fuel, and 5 tons of atmospheric pollution every weekday of operation. Car-pool lane effectiveness is a false myth, perpetuated by well-meaning but incomplete, wishful thinking.
JACK MALLINCKRODT
Drivers for Highway Safety
