Washington Post 5/18/06
----snip
Think Virginia, and especially HOV, is overrun with hybrids? Well, you're right. There are 11,843 hybrids in the D.C. area and 8,280 of them are in Virginia. And these aren't a bunch of crunchy liberals in Arlington. These are primarily folks in the outer suburbs who are presumably using hybrids to drive in HOV without any passengers. The highest concentration of hybrids is in Prince William County, where there are 14.8 hybrids per 1,000 households. Loudoun comes next, followed by Fairfax.
---snip
Link to article