55 mph Speed Limit Day Date in the current year: January 2, 2025

A speed limit is the legal maximum speed at which a vehicle may travel on a given stretch of road. Most countries have set speed limits for road safety and to reduce the environmental impact of road traffic (emissions, vibration and noise); they are enforced by police and judicial authorities. Depending on the country, speed limits may be measured in kilometers per hour (km/h) or miles per hour (mph).

Interestingly, speed limits predate the use of automobiles. For example, in 1652, the Dutch colony of New Amsterdam in North America passed a law limiting the speed of horse-drawn wagons, carts, and sleighs. The first speed limits for mechanically propelled vehicles were set in the United Kingdom by the Locomotive Act 1861 (10 mph on open roads and 5 mph in inhabited areas).

The first state in the United States to adopt a numerical speed limit for motorized vehicles was Connecticut in 1901; the limit was set at 12 mph in cities and 15 mph in rural areas. By 1912, numerical speed limits had been established in all but 12 states. As motor vehicles became faster, speed limits increased accordingly.

Until 1974, each state set its own speed limits. The situation changed with the passage of the Emergency Highway Energy Conservation Act of 1974 that effectively prohibited speed limits higher than 55 mph. The law was passed in response to the oil price spikes and fuel shortages caused by the 1973 oil crisis; its primary goal was to reduce gasoline consumption in the United States. The limits (50 mph for cars and 55 mph for buses and trucks) were based in part on the belief that vehicles achieve maximum efficiency at these speeds.

Richard Nixon signed the Emergency Highway Energy Conservation Act into law on January 2, 1974; the new speed limit went into effect 60 days later. It was highly unpopular with drivers nationwide, and compliance was very low. In 1987 and 1988, the speed limit was modified to allow the speeds of up to 65 mph on certain rural roads. The National Maximum Speed Limit was repealed by Congress in 1995, and the authority to set speed limits was fully returned to the individual states, with most states reverting to their pre-1974 speed limits.

Although the Emergency Highway Energy Conservation Act was highly controversial and the speed limit it set was widely unpopular, some people observe 55 mph Speed Limit Day on January 2. Regardless of how you feel about speed limits, it is a good time to think about road safety, energy conservation, and the environmental impact of vehicles.

You can celebrate 55 mph Speed Limit Day by pledging to never drive the speed limit, paying off your outstanding speeding tickets if your have any, educating your children safety, looking up speed limits in different countries just for the fun of it, and spreading the word about the holiday on social media.