Q. National Speed Limit
Speed limits are regulated by the states, not by the US DOT.
We suggest that you submit your comments to your elected federal or state representatives, asking for their assistance. For contact information, please see http://www.usa.gov/Agencies.shtml
For more information on what was known as the "national speed limit," please see the Federal Highway Administration web site at http://www.fhwa.dot.gov/interstate/faq.htm#question13
For information on the relationship between speed and fuel efficiency, see: http://fueleconomy.gov/feg/driveHabits.shtml
For information on how gas prices are established and how they fluctuate, Answer Link