JEFFERSON CITY, MO — August 20, 2026 (STL.News) Missouri drivers expecting to legally travel 75 mph on some rural interstate highways beginning Aug. 28 will have to wait.
Although a new Missouri law takes effect Aug. 28 allowing maximum speed limits of up to 75 mph on eligible rural interstates and freeways, the Missouri Department of Transportation says motorists should not assume the higher limit automatically takes effect when the law does.
MoDOT is still evaluating which sections of Missouri highways can safely support the higher speed limit and has not announced a date when the first 75 mph signs will go up.
For drivers, the immediate rule is straightforward:
Obey the speed limit posted on the highway sign.
If a rural stretch of Interstate 70 is posted at 70 mph on Aug. 28, the legal limit remains 70 mph. The new state law does not give motorists permission to drive 75 mph until MoDOT actually changes the posted limit.
The Missouri State Highway Patrol says troopers will continue enforcing posted speed limits.
Missouri law allows 75 mph but doesn’t require it
The distinction between what the Legislature authorized and what MoDOT must implement is important.
The legislation increases Missouri’s allowable maximum speed limit from 70 mph to 75 mph on qualifying rural interstates and freeways.
But lawmakers did not simply order every 70 mph interstate sign in Missouri replaced with a 75 mph sign.
Instead, the legislation gives transportation officials authority to establish higher limits where they determine those speeds are appropriate.
That means 75 mph is a maximum permitted under state law, not an automatic statewide speed limit.
The legislation originated with Republican state Sen. Jamie Burger of Benton and was approved during the 2026 legislative session. Gov. Mike Kehoe subsequently signed the measure into law.
MoDOT says safety reviews will take time
MoDOT says it is now evaluating potentially eligible highway segments.
The department told KCTV that several factors must be considered before increasing a particular roadway’s speed limit, including:
- Traffic volume
- Crash history
- Overall safety
- Terrain
“MoDOT has the responsibility to set speed limits that are reasonably safe considering the various factors of each roadway, such as traffic volume,” the department said in a statement provided to KCTV.
MoDOT said passage of the legislation allows it to raise limits where a higher speed is considered reasonably safe, but emphasized that evaluating those locations will take time.
The agency has not provided a firm timetable for completing the evaluations or installing the first 75 mph signs.
That creates an unusual situation beginning Aug. 28: Missouri law will permit 75 mph limits, but drivers may not immediately encounter any highways where 75 mph is actually legal.
Don’t automatically drive 75 mph on Aug. 28
The Missouri State Highway Patrol is emphasizing that point.
“For now, the posted speed limit, whatever sign you see on the roadway, is going to be the speed limit that we enforce,” Highway Patrol Sgt. Justin Ewing told KCTV.
In practical terms, drivers should not add five miles per hour to the speed displayed on existing signs.
A 70 mph sign means 70.
A 65 mph sign means 65.
Only after MoDOT formally establishes a 75 mph limit and appropriate signs are installed should motorists treat 75 mph as the legal maximum for that section.
The distinction could prevent considerable confusion — and potentially speeding tickets — after the new law takes effect.
I-70 could eventually see higher limits
Some of the greatest interest will likely involve Interstate 70, particularly rural sections between Missouri’s metropolitan areas.
During the legislative process, MoDOT indicated that most interstates and freeways currently posted at 70 mph could potentially qualify for consideration if they are outside urban areas.
MoDOT spokesman Jacob Luecke told ABC 17 earlier this year that “most interstates and freeways currently posted at 70 miles per hour could potentially increase to 75 miles per hour.”
That doesn’t mean all of those highways ultimately will.
Individual roadway characteristics will determine which sections receive higher limits.
Drivers traveling through the St. Louis and Kansas City metropolitan areas also should not expect the higher rural maximum to translate automatically into higher urban interstate limits.
Higher speed limit generated safety debate
The legislation drew both support and opposition as it moved through the General Assembly.
Supporters argued Missouri’s existing 70 mph maximum was unnecessarily low on appropriate rural interstate sections, particularly when neighboring states already permit higher speeds.
Kansas raised its maximum interstate speed limit to 75 mph in 2011.
Nebraska has also increased limits on certain divided highways.
Supporters have additionally pointed out that raising the maximum to 75 mph does not require motorists to drive that fast.
A driver who is more comfortable traveling 65 or 70 mph can continue doing so, as long as they otherwise follow traffic laws.
Safety advocates, however, warned lawmakers that higher speeds can increase crash severity.
Speeding was reported as a factor in approximately 34% of Missouri’s fatal crashes, compared with about 29% nationally, according to information presented during debate over the legislation.
The National Road Safety Foundation also raised concerns about the relationship between higher speeds and serious injuries.
Those concerns help explain why MoDOT isn’t simply replacing every qualifying 70 mph sign on Aug. 28.
Missouri has an enormous highway system
Evaluating the change also represents a significant undertaking for MoDOT.
Missouri maintains one of the largest state highway systems in the country.
MoDOT says the transportation system includes approximately 33,814 miles of roads and 10,427 bridges.
The department is simultaneously managing major infrastructure projects, including the statewide expansion of I-70 and planning and construction associated with improvements to Interstate 44.
That makes implementing the speed-limit law more complicated than changing a few highway signs.
Engineers and traffic planners must consider engineering and traffic data, make decisions about individual highway sections, change signs, and inform motorists where the higher limits apply.
I-70 is already undergoing major changes
The speed-limit debate also comes as Missouri invests heavily in Interstate 70.
The state is widening approximately 200 miles of I-70 between Blue Springs and Wentzville to three lanes in each direction.
The massive project is changing one of Missouri’s most heavily traveled transportation corridors and will continue affecting motorists for years.
Construction zones will remain governed by their separately posted speed limits regardless of whether surrounding rural interstate sections eventually increase to 75 mph.
Drivers will therefore need to pay close attention to signage.
A highway might eventually carry a 75 mph limit through one rural section before dropping substantially when approaching construction, congestion or an urban area.
Why didn’t MoDOT prepare before Aug. 28?
Some motorists may reasonably wonder why the state authorized the change without having the new limits ready when the law takes effect.
MoDOT’s explanation is largely procedural.
The department could not treat the legislation as final until it completed the legislative process and was signed into law.
Only then could transportation officials begin implementing the authority lawmakers granted and make final determinations about individual roadways.
The law also doesn’t instruct MoDOT to raise every eligible limit.
The department still decides where 75 mph is reasonably safe.
That requires more analysis than simply identifying every road currently posted at 70 mph.
Higher limits could eventually shorten trips slightly
For motorists traveling long distances across Missouri, a five-mile-per-hour increase could modestly reduce travel times.
The difference would be relatively small on shorter trips but more noticeable across hundreds of miles.
Still, the higher limit represents a maximum, not a required travel speed.
Weather, traffic, construction and road conditions can make driving at the posted maximum unsafe even when it is technically legal.
Missouri’s Highway Patrol is reminding drivers that increased speed comes with increased responsibility, and that speed remains an important factor in serious and fatal crashes.
Watch the signs, not the calendar
For Missouri motorists, the most important date may ultimately not be Aug. 28.
It will be the date MoDOT changes the sign on the particular highway they are traveling.
Until that happens, existing speed limits remain enforceable.
MoDOT says it will communicate updates as it makes decisions about eligible locations, but the department has not announced when the first 75 mph roadway will become operational.
The new law therefore changes what Missouri can do beginning Aug. 28.
It does not immediately change how fast every Missouri motorist can drive.
For now, drivers tempted to begin traveling 75 mph on rural interstates should follow the simplest rule available:
Read the sign.
If it still says 70 mph, the speed limit is still 70.
Editor’s note: MoDOT had not announced a firm implementation date or a final list of Missouri highways that will receive 75 mph speed limits at the time of publication. Drivers should follow posted speed-limit signs.
