Seven States Still Hold Trucks to a Lower Speed Limit
Date Published
A split speed limit means heavy vehicles are held below the limit that passenger traffic runs on the same road. Seven states still do it.
The list
California holds trucks to 55 statewide under Cal. Veh. Code 22406, against a car limit of 65 or 70. That is the widest gap in the country.
Oregon holds motor trucks over 10,000 lb GVWR, and truck tractors over 8,000 lb GVWR, to 55 on any highway under ORS 811.111, with named segments running higher: on Interstate 84 from the eastern city limit of The Dalles to the Idaho line, trucks may run 65 and cars 70.
Washington holds vehicles over 10,000 lb gross weight and all combinations to 60 under RCW 46.61.410, while cars reach 70 on raised rural interstate segments.
Montana holds trucks over one ton rated capacity to 70 on interstate under 61-8-312, against 80 for cars.
Michigan holds trucks of 10,000 lb or more, truck tractors and combinations to 65 where the posted limit is above 65, under MCL 257.627.
Indiana holds vehicles other than buses with a declared gross weight over 26,000 lb to 65 on rural interstate under IC 9-21-5-2, against 70 for everyone else.
Arkansas holds commercial motor vehicles to 70 on a rural four-lane divided controlled-access highway under A.C.A. 27-51-201, against 75 for other vehicles.
What changed
Idaho left this list in 2026, when chapter 108 amended Idaho Code 49-654 to make the limits for five-or-more-axle vehicles over 26,000 lb the same as for lighter vehicles.
It follows a long trend. States have been equalising splits steadily, and any list of split states is accurate only as of the date it was compiled.
Reading the gap, not the number
A truck limit on its own does not tell you much. Seventy miles per hour means something different in Montana, where cars run 80, than in Arkansas, where they run 75. The differential is the operationally meaningful figure, and it is the one most tables omit.