Do you think that a national mandated speed limit of 45 mph should be set to conserve gasoline?

its been tested and it takes more gas to maintain a car at a lower speed than it does at 55 miles per hour,that seems to be the most desired speed for most cars to get the maximum gas mileage ,most cars will shift to much up and down when trying to maintain lower speeds and that actually uses more gas,they may be lowering the speed limits again anyway on the freeways if gas continues to rise like it is,good luck.