Speed limits in the USA are set by the state rather than at national level and are posted in miles per hour (mph) and generally use increments of 5mph. Some states have reduced speed limits for trucks and when driving at night. The general rule of thumb is that states with vast open freeways will tend to have higher speed limits, whereas smaller states with higher populations and busier freeways are likely to have the slower maximum speed limits.
Washington D.C unsurprisingly has the lowest speed limit in the USA at just 55mph, although technically it doesn’t have any rural freeways, so its fastest roads are urban freeways. Texas has the highest speed limit in the USA at a brisk 85mph. Taking all states into account, the average maximum speed limit in the USA by state is 69.8mph, whilst the median speed limit is 70mph.
Are there Minimum Speed Limits in the USA
Some states impose a minimum speed limit of 40mph, typically on freeways (motorways) to ensure that traffic using them keeps to a safe speed and flow of traffic.
Are there Speed Limits at Night in the USA
Some states impose reduced speed limits when driving at night. Where these are applied, any speed limit sign will state the general speed limit for the road (white sign / black text) with the night time speed limit immediately below with a black sign with white text. Whilst rare, you’re likely to see night time speed limits in the following locations;
- Arizona – where no street lights present
- Florida – named ‘Panther Zones’ or Panther X-ing’
- Colorado – Highway 13 drops from 65mph by day to 55mph at night
- Washington – Highway 20 drops to 45mph at night due to high number of deer on the road at night
Rural Freeway Speed Limits by State