Missouri’s new 75 mph law takes effect Friday, but drivers will not see immediate changes

Missouri’s new speed-limit law takes effect Friday, August 28, but drivers should not assume they can immediately drive 75 mph on rural highways.

Senate Bill 1408 raises the statutory maximum speed limit on eligible rural interstates and freeways from 70 mph to 75 mph. The law does not automatically change the speed limit on every road covered by the new maximum.

Until MoDOT completes its review, a location-specific change is approved and new signs are posted, the number on the roadside sign remains the enforceable limit.

What SB 1408 changes

Gov. Mike Kehoe signed SB 1408 in July. The Missouri Senate’s bill record lists August 28, 2026, as the effective date and shows the measure as signed by the governor.

The enacted bill text defines a rural interstate as part of the federal interstate system outside an urban area. It sets the uniform maximum speed limit on rural interstates and qualifying freeways at 75 mph, up from 70 mph.

The law leaves other categories unchanged under the statutory schedule. Rural expressways remain subject to a 65 mph maximum, while interstates, freeways and expressways in urbanized areas remain at 60 mph. Other roads remain governed by their applicable statutory or posted limits. The new law does not generally apply to ordinary U.S. routes or two-lane roads.

Why signs will not change automatically

MoDOT and the Missouri Highways and Transportation Commission still control the process for setting individual speed limits on state roads. Under the law, the commission may set a limit higher or lower than the uniform maximum when MoDOT recommends the change.

The law also creates a rebuttable presumption for enforcement that the posted speed limit is the legal speed limit. In practical terms, the effective date creates authority for possible increases; it does not give drivers a statewide 75 mph authorization.

MoDOT Director Ed Hassinger told ABC 17 News that drivers should continue following the signs after August 28. MoDOT’s own update says no changes will take effect until the department completes its evaluation.

How MoDOT is reviewing highways

MoDOT says it is reviewing eligible locations individually rather than applying one limit across all rural interstates and freeways. The department is considering:

Current traffic volume
Truck traffic volume
Crash history
Terrain
Road design and safety countermeasures
Speed limits in neighboring states near eligible Missouri border areas
Active construction

The Jefferson City News Tribune reported that the review would continue past the law’s effective date. MoDOT is aiming to complete the evaluation and provide an update by the end of 2026, but that timing is a target rather than a guaranteed deadline.

I-70 will not be raised during current construction

Interstate 70 will not receive a higher speed limit while the Improve I-70 rebuild and expansion program is underway. MoDOT cited active construction and work-zone conditions in excluding the corridor from changes during the project.

The department plans to reevaluate I-70 after the construction program is complete. Current work-zone restrictions and any other posted limits on the corridor therefore continue to control.

What drivers should do now

On Friday, drivers should obey the posted speed limit on every highway, including temporary reductions through construction zones. A 70 mph sign remains 70 mph, and a lower work-zone sign remains enforceable, regardless of the new law’s effective date.

Some rural interstate or qualifying freeway segments may eventually receive 75 mph limits after MoDOT completes its review, makes recommendations and the commission approves the change. Drivers should look for an official sign change before adjusting their speed.

For now, the immediate effect of SB 1408 is a higher legal ceiling for certain roads—not an automatic increase on Missouri’s highway signs.

Sources

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