Are cars designed to get the best gas mileage at a certain speed and if so, what is the target speed?

gdec1

A vehicle will reach its maximum fuel efficiency at 55 to 60 mph, according to the FTC. Anything over 60 mph will decrease gas mileage. A car or truck’s maximum gas mileage is dependent on the vehicle’s engine, weight, drivetrain (transmission, rear end) and aerodynamic efficiency (the sleeker the car, the easier it cuts through the air, thus saving gas). However, achieving a vehicle’s maximum fuel efficiency is solely dependent on the driver, so don’t blame your Cavalier the next time you get 10 mpg. A combination of driving techniques and vehicle maintenance can ensure a properly running and gasoline-efficient car or truck. http://www.ferris.edu/TORCH/news.htm#6 Aug 16 06, 7:44 AM

BungeeAZ

Speed limits were set at 55 in the late 70's and early 80's to prevent overconsumption of gas. In the 90's some states raised the speed limit to 65, and more recently, some states have areas where you can drive 75. Cars are more fuel efficient now than they had been, especially with the inventions of direct fuel injection and variable valve timing. Some cars built within the last 12-24 months have double direct fuel injection where it injects fuel as the pistons move up as well as down. Triptronic automatic transmissions also increase fuel efficiency by allowing the driver to force upshifts over and above what the car's computer would choose. Higher gears mean that the engine wouldn't have to work as hard to make the car go, thereby increasing fuel efficiency. Just remember keep your tires properly inflated. Do not overinflate. For maximum fuel efficiency, you can inflate your tires to the maximum allowed on the tire, the drive characteristics of the car will change. Keep your car well maintianed. Don't fly from a standstill. And remember to change your gas filter when scheduled. Gas tanks have sediment which are filtered by the gas filter on the fuel's way to the engine. Happy motoring. Aug 16 06, 10:16 AM