Gas prices are extremely high right now. It appears that the high prices are causing people to buy less SUVs and more economy vehicles.
There is also a video from a fuel expert on CNN.com on how to save money on fuel costs. His primary recommendations are to drive less, carpool, lump errands together, give the smaller car to whomever drives the most in the family, etc.
Other useful tips that I have learned about from a group called the "hypermilers" are the following:
1. Tailgating- Drag the vehicle (preferably a tractor-trailer) in front of you on the highway to cut down wind resistance. They follow the preceding car by about 1 second difference, rather than the 4 seconds that is generally considered safe. This was actually tested out on the show Mythbusters on the Discovery Channel. They found that fuel efficiency was increased by an exponential function as the trailing distance decreased from 200 feet to 2 feet. The gain was approximately 4-5% at 200 feet behind a tractor-trailer, and increased to about 41% in fuel efficiency at 2 feet.
Of note, they also tested whether driving with the "windows down/AC off" or "windows up/AC on" is more fuel efficient. Initially, it appeared that "windows up/AC on" was superior (according to the MPG digital reading), but upon a retest with a more accurate method the windows down method was slightly superior in terms of fuel efficiency.
2. Overinflate the tires- this can increase fuel-efficiency by 1.4% for every 1 PSI increase
3. Drive at constant speeds- fairly obvious...avoid rapid acceleration/deceleration cycles
4. Pulse and glide- glide in neutral when the slope of the road allows (keeping the transmission engaged causes braking)
5. Coasting to a stop (in neutral)
6. Parking on a hill facing down-hill (when need to move again, can just put the car in neutral and just start rolling without starting the engine)
I don't advocate some of these manuevers, as some are unsafe (particularly tailgating and coasting). If you are in neutral and suddenly need to accelerate, you will lose a second or two until the transmission re-engages.
Of note, there is a condition called "Nempimania", which is an obsession with getting the best fuel economy possible from a hybrid car.