I heard mention of the Caltrans study this morning on KCBS news radio, then found this article in today's San Jose Mercury-News.

• One Less Reason to Hate Hybrids
  Stickered Cars Aren't Clogging Bay Area Carpool Lanes
  By Gary Richards
  Mercury News
  Article Launched: 06/12/2007 01:30:58 AM PDT
  
  "Caltrans' latest traffic count shows that only 6 percent of cars in the region's busiest diamond lanes are exempt hybrids - Toyota Priuses, or Honda Civics or Honda Insights - containing just one occupant. That also includes vehicles powered by natural gas or electricity, which have no limit."

I wish the Mercury-News had used a different headline for the article, one with less of an us-and-them attitude.