Speed limits in various states, including Texas, Utah, Massachusetts, New Hampshire, Connecticut, Ohio, Oregon, and Rhode Island are prima facie. Other states have a hybrid system: speed limits may prima facie apply up to a certain speed or only on certain roads. For example, speed limits in California up to 55 miles per hour or 65 miles per hour on highways are prima facie, and those at or above those speeds are absolute.  The National Maximum Speed Limit (NMSL) was a provision of the U.S. federal government`s Emergency Highway Energy Conservation Act of 1974 that effectively prohibited speed limits of more than 55 miles per hour (89 km/h). It was designed in response to oil price spikes and supply disruptions during the 1973 oil crisis and remained in effect until 1995. The highest speed limits are typically 70 mph (113 km/h) on the West Coast and eastern states inland, 75 to 80 mph (121–129 km/h) inland states and Arkansas, Louisiana, Maine and Michigan; and 65 to 70 mph (105 to 113 km/h) on the East Coast. Alaska, Connecticut, Delaware, Massachusetts, New Jersey, New York, Puerto Rico, Rhode Island and Vermont have a maximum limit of 65 mph (105 km/h) and Hawaii has a maximum limit of 60 mph (97 km/h). The District of Columbia and the U.S.
Virgin Islands have a top speed of 55 mph (89 km/h). Guam and the Northern Mariana Islands have speed limits of 45 mph (72 km/h). American Samoa has a top speed of 30 mph (48 km/h).  Two U.S. Minor Outlying Island territories have their own speed limits: 40 mph (64 km/h) on Wake Island and 15 mph (24 km/h) on Midway Atoll. , Unusually for any state east of Mississippi, much of Interstate 95 (I-95) in Maine north of Bangor allows up to 75 mph (121 km/h), and the same goes for up to 600 mi (966 km) of highway in Michigan. Parts of the highway systems in Idaho, Montana, Nevada, Oklahoma, South Dakota, Texas, Utah, and Wyoming have shift limits of 80 mph (129 km/h). The highest speed limit in the country is 85 mph (137 km/h) and can only be found on Texas State Highway 130, a toll road that bypasses the Austin metropolitan area for long-distance traffic. On the other hand, the Insurance Institute for Highway Safety (IIHS) released a study in April 2019 that monitored global weather trends, unemployment rate, percentage of young drivers, and seat belt use rate. The study concluded that increasing speed limits not only increases vehicle speed, but can also cause additional fatalities: «A 5-mile increase in speed limits was associated with an 8.5% increase in fatality rates on highways/highways and a 2.8% increase on other roads.»  The California Trucking Association, the largest trucking association in the United States, objected to different speed limits on the basis that they were «not appropriate for safety reasons».  During World War II, the U.S.
Office of Defense Transportation imposed a national «victory speed limit» of 35 mph from May 1942 until August 1945, when the war ended, in order to save gasoline and rubber for the U.S. war effort, at the end of the war. For 13 years (January 1974–April 1987), federal law held federal funds in trust for highways for states that had speed limits greater than 55 mph (89 km/h).  From April 1987 to December 8, 1995, an amended federal law authorized speed limits of up to 65 mph (105 km/h) on rural interstate and rural highways built to Interstate Highway standards. The speeding ticket is the most common speeding ticket in most U.S. jurisdictions and is usually paid without incident. However, motorists sometimes face a driver`s licence suspension or other severe penalties through a ticket, including insurance increases, especially if the violation is considered «excessive» or if the motorist has previously committed traffic violations. If you want to get the best possible result for your ticket, you should talk to a traffic lawyer in your area. The law sets the maximum at 70 miles per hour, allowing the Texas Transportation Commission to set a speed limit of 75 miles per hour or 80 miles per hour or 85 miles per hour if the highway is designed for that speed on the road network if that speed is deemed safe and appropriate according to a traffic or engineering study.
An 80 mph speed limit in 10 counties on Interstate 10 and Interstate 20 is also allowed. The number 55 has become a popular abbreviation for the 55 mph speed limit. For example, a hand with a pair of five in Texas Hold`em poker is called a «speed limit».  Rock musician Sammy Hagar released «I Can`t Drive 55,» a hit single protesting the rule. The title of The Minutemen`s critically acclaimed double album, Double Nickels on the Dime, refers to NMSL and Sammy Hagar`s single. Films like Smokey and the Bandit and The Cannonball Run were popular and humorous taunts at the NMSL. Footnote 1 In Hawaii, the speed limit is set by a county order or by the Director of Transportation. ↩ In 1984, an extensive study by the National Research Council found that lower speed limits saved 3,000 to 5,000 lives in 1974 and 2,000 to 4,000 lives a year thereafter, due to slower and smoother speeds on U.S. roads.  A constant speed of vehicles in a traffic flow ensures the safest use. Published speed limits can help keep traffic flowing, provided the majority of drivers find the appropriate speed limits.
This is called «voluntary compliance.» To achieve voluntary compliance in the best possible way, speed limits must be consistent across the state. Speed limits also give motorists an idea of a reasonable speed to drive in an unfamiliar place. A black and white sign indicates the maximum speed a driver is allowed to drive in ideal conditions. It may be of legal value or must be approved by the Commissioner of Transport. Footnote 2 In Idaho, the speed limit on certain stretches of highway can be increased to 80 mph based on engineering and traffic study.