The reduction is aimed at improving safety.
The 40-mph signs will be put up starting at 9 p.m., Wednesday. All signs will be in place by 6 a.m., Thursday, Sept. 19. By state law, the new speed limit goes into effect when signs are posted.
The 40-mph speed limit will cover Range Line Road between Newman Road and 44th Street. Following studies of traffic along Range Line Road, MoDOT decided to lower speed limit to 40 mph.
MoDOT traffic engineers found the number of crashes along Range Line Road is higher than the statewide average for five-lane roads. Many of these crashes are rear-end type as cars and trucks turn onto and off of Range Line Road at the many streets and business driveways.
The 40-mph is comparable to the 40 mph speed limit on Glenstone Avenue in Springfield where similar issues of safety and access are present.
The Joplin City Council in August approved an ordinance supporting the speed limit reduction.