"Brian D. Taylor, director of UCLA's Institute of Transportation Studies, argues against linking hybrids with car pool lanes, which he says exist for an unrelated purpose: taking cars off the road."
Yes, and part of the reason for taking cars off the road is to increase the fuel efficiency per passenger mile. Hybrids also do this.
"In April 2003, about 2,500 hybrid drivers in Virginia registered their cars and asked for 'clean fuel' license plates, allowing them to use the car pool lanes, Morris said. By May of this year, the number had more than tripled – to about 9,000."
Even if ALL NINE THOUSAND HYBRIDS ARE ON THE SAME ROAD AT THE SAME TIME, this isn't what's increasing congestion in the HOV lanes in Northern Virginia. These are roads that see several times that amount of traffic in an hour. As an example, I-66 in Northern Virginia sees nearly 200,000 vehicles per day.
Non-issue.