Speed limits on the majority of streets in Minneapolis and St. Paul are dropping to 25 and 20 miles an hour.
The news was announced at a joint press conference featuring Minneapolis and St. Paul leaders, sparking a 6-month process to replace speed limit signs across the two cities.
The limit is reducing from 30 mph on city-owned streets to 25 mph on arterial streets and 20 mph on residential streets.
It comes after state lawmakers gave cities the power to set their own speed limits last year.
The move will see more than 1,000 speed limit signs changed between now and October. The citywide speed limit in both cities will be 20 mph unless otherwise signposted.
It follows a study by both cities' public works departments on how best to improve safety on city roads.
"The lower speed limits are in line with national trends toward lower urban speed limits to support safety," a statement from the cities read.
"Lower traffic speeds reduce the likelihood of a crash and make all types of crashes less likely to lead to death or a life-changing injury. A person hit at 35 mph is three times as likely to die as someone hit at 25 mph."
Some city streets will keep the 30 mph limit, namely busy roadways used heavily by transit such as Park and Cedar avenues in south Minneapolis, Central Avenue in northeast Minneapolis, and Penn Avenue in north Minneapolis.
There is no speed reduction however for Lyndale Avenue South, which has been the site of a number of protest in recent months because of the number of traffic incidents, particularly those involving pedestrians.
You can find a map showing how speed limits will change in Minneapolis here.