Don't mean for this to be a political discussion, but it seems like that's where a few of the of GM monstrosity class hybrids have gone to. LA Car.com - The Cars and Culture of Southern California Magazine & Directory - BACK SEAT DRIVING - JULY 2009
Surprise! Surprise! And most are hybrids in name only...awful fuel economy relative to the average car.
If you're driving a car on the taxpayer dime, it should be no more than a fully loaded Prius V, Camry Hybrid or XLE I-4, Civic Hybrid, Accord EX-L but preferably a rent-a-car spec Impala, Malibu, Fusion or Charger.
Why not give them the same spec vehicles that the fire and police and other agencies get. Ford Taurus, Crown Vic, Dodge Charger.
The 'Vic is overkill, it's a V8 that isn't too terribly good at gas mileage but it is also a very reliable and solid car. I think the Charger 3.5L V6 is a much better choice, or the V6 Chevy Impala.
Legislators don't need vehicles as big as the Taurus and Charger, I think; they are fairly large cars. Plus the Taurus and Charger get something like 22 MPG. Obviously, Priuses would be a good idea both on cost and environment. The LA Times says that the state keeps the car, and the resale value of Priuses is good. From American nameplates (though I see Lexus and Toyota on there), at roughly the $30K level, why not the Ford Fusion hybrid? Good ratings and much better MPG; I'd recommend that.
If there's a reason they should be driving those three models, it's that there (may) be pre-existing state-operated infrastructure for serving these vehicles as opposed to requiring relatively expensive dealer-provided service.