Truck Speed Limits by State and the Seven States Where Trucks Run Slower Than Cars

California holds a loaded tractor-trailer to 55 mph on a rural interstate where the car next to you can legally do 70. That 15 mph gap is the widest in the country. Truck speed limits by state differ from car limits in seven states as of October 2026, plus eight Illinois counties around Chicago and St. Louis. Idaho was on that list until July 1, 2026, when it let trucks run 80 wherever cars do.

Seven states set a lower limit for trucks than for cars

The numbers come from the Insurance Institute for Highway Safety table of maximum posted speed limits, current as of October 2026, with Idaho's July 2026 change added. A range like 75–80 means the higher limit is posted only on specific segments. They are ceilings. The sign over your lane is the law on that stretch, and work zones, curves and city limits drop it fast. Click a state for the ASTEL page about hauling there.

City interstates drop to 55 in nine states

The rural number is the one drivers quote, but much of a week happens inside metro areas. Nine of the 48 states cap urban interstates at 55: Connecticut, Delaware, Illinois, Indiana, New Jersey, Oregon, Rhode Island, Vermont and West Virginia. Missouri and Washington sit at 60. In Indiana that means a truck goes from 65 to 55 as I-65 enters Indianapolis.

Cities also post their own lower limits on freeways, often 50 or 45 through interchanges and bridges. A truck that holds the rural speed into town is the one that meets a trooper at the first exit. Slow down when the skyline shows up.

California holds every truck with three axles to 55

Section 22406 of the California Vehicle Code sets 55 mph for any truck or truck tractor with three or more axles and for any truck pulling another vehicle. A five-axle reefer combination fits both tests. The limit applies on every road in the state, including the stretches of I-5 and I-15 where cars are signed for 70.

California also wants those vehicles in the right-hand lane or in a lane signed for trucks. Long grades such as the Grapevine on I-5 are where that 55 and a low gear matter most. Our mountain driving guide covers the brake side of those grades.

Drivers coming in from Nevada or Arizona feel it at the state line, where the limit falls from 75 or 80 to 55 in a single sign and the CHP knows exactly which trucks forget. Set the cruise before the border.

Washington and Oregon split speeds by weight and by road

Washington sets 60 mph for trucks over 10,000 pounds, and cars may run 70 on most rural interstates and 75 on signed segments. The 60 holds on I-90 across the Cascades and on the long, flat stretches east of Ellensburg, where it feels slow.

Oregon is the patchwork state. Its statute still says 55 for heavy trucks, but the state posts higher truck limits by segment. Since 2017 most of rural I-5 has carried a 60 mph truck limit, while on I-84 east of The Dalles toward the Idaho line trucks may run 65 next to cars doing 70. Near Roseburg, I-5 drops to 55 for trucks again. Read the signs in Oregon and don't trust the number you saw an hour ago.

Michigan, Indiana and Arkansas cap trucks at 65 or 70

Michigan raised car limits to 75 on some rural freeways in 2017 and set the truck limit at 65. On I-75 north of Bay City you can be doing exactly the limit while traffic passes you at 80. Indiana runs 70 for cars and 65 for trucks over 26,000 pounds on rural interstates, so the I-65 and I-70 corridors through the state carry that split.

Arkansas raised its car limit to 75 on rural interstates and set the truck limit at 70. On I-40 between Little Rock and Fort Smith the gap is only 5 mph, but it is still a ticket if a trooper paces you at 74.

Montana gives trucks 70 where cars get 80, and Idaho dropped its split

Montana posts 80 for cars on rural interstates and 70 for trucks, which on I-90 and I-94 means a long day of cars passing you at 10 mph or more while you sit legally in the right lane. It wears on you.

Idaho went the other way. House Bill 664 took effect on July 1, 2026, and made the limit for vehicles with five or more axles over 26,000 pounds the same as for other traffic. Where I-84 and I-86 are posted at 80, a truck may now do 80. The Idaho State Police said the goal was fewer crashes from cars and trucks running at different speeds. The Idaho Trucking Association expected little change, since a loaded truck often can't hold 80 on the hills anyway. Urban stretches, such as I-84 through Boise, stay at 65 for everyone.

Around Chicago and St. Louis, eight Illinois counties hold trucks to 55 and 60

Illinois allows 70 on rural interstates for cars and trucks alike. Eight counties opted out with their own ordinances: Cook, DuPage, Kane, Lake, McHenry and Will around Chicago, plus Madison and St. Clair across the river from St. Louis. In those counties the maximum for large trucks is 55 inside urban districts and 60 outside them.

It matters for Chicago runs. ASTEL's yard is in Chicago, and the yard has showers, a sauna and a laundry for drivers between loads. Every trip home to the yard runs through Cook or Will County, where the truck limit is lower than the car limit on the same interstate. The Chicago-area tollways add their own rules, covered in our guide to truck tolls.

Texas posts 85 on SH 130, and your governor decides the rest

State Highway 130, partly a toll road between the Austin area and Seguin, carries an 85 mph limit, the highest posted in the United States. Sections of I-10 and I-20 in West Texas are posted at 80, and because Texas has had no separate truck limit since 2011, on paper an 18-wheeler may run any of those speeds.

In practice the truck decides. Most fleets set the engine governor well below 80, and a truck governed in the 60s cannot use an 85 limit at all. There is no federal speed-limiter rule. FMCSA and NHTSA withdrew their proposal for heavy-truck speed limiters on July 24, 2025 (90 FR 34822), so governor settings stay a carrier decision. Ask about it when you compare companies. It changes how many miles you can run in a day, as the trip math below shows.

Fifteen over is a serious violation in any state

State limits differ. The federal penalty doesn't. Under 49 CFR 383.51(c), driving a CMV 15 mph or more over the posted limit is a serious traffic violation. A second serious violation within three years takes your CDL for 60 days. A third one takes it for 120 days.

The math gets ugly in the split states. Doing 70 on I-5 in California, where cars are legal at that speed, is 15 over the truck limit. In Nevada it's legal. The full list of violations that cost a CDL, including the ones in your own car, is in our guide to CDL disqualification.

Traffic school won't hide it. Under 49 CFR 384.226 a state may not mask, defer or divert a CDL holder's conviction for a moving violation in any vehicle, so the ticket lands on your record even when a car driver in the same court would get it dismissed. Recruiters pull that record when you apply.

Tickets also cost money that never shows up on the citation. ASTEL pays a Safety bonus of +$0.02 a mile, and one of its conditions is three months without tickets or DOT violations. A single speeding stop resets that clock.

A truck at the limit still makes 600 miles a day

ASTEL's expectation is 600–700 miles a day in 11 hours of driving. Divide it out and that is an average of about 55–64 mph over the whole shift, fuel stops and city miles included. You get there by using every legal hour, not by running 10 over. Our hours-of-service guide explains how the 11 and 14 hours fit together.

California is the honest exception. At a 55 mph ceiling, 11 hours of driving tops out around 605 miles if nothing slows you down, so a day spent entirely inside California will land at the low end. Dispatch knows. Build the speed limits of each state into your plan with the steps in truck trip planning.

Lower speed also pays at the pump. Fuel burn climbs fast above 60 mph, and ASTEL's Fuel bonus adds up to $0.02 a mile for good MPG and fueling by the rules. The numbers on speed and fuel are in our fuel-efficient driving guide. A truck that holds 62 in the right lane often finishes the week with more money than one that chased 70.

Frequently asked questions

What is the speed limit for semi trucks in California?

55 mph on every road in the state. California Vehicle Code 22406 applies it to any truck or truck tractor with three or more axles and to any truck pulling a trailer, even where cars are posted at 70. Those trucks are also expected to stay in the right-hand lane or a lane signed for trucks.

Which states have different speed limits for trucks and cars?

As of October 2026, seven states set a lower truck limit on rural interstates: California, Washington, Oregon, Michigan, Indiana, Arkansas and Montana. Eight Illinois counties around Chicago and St. Louis also cap large trucks at 55 and 60. Idaho ended its split on July 1, 2026.

What is the fastest a semi truck can legally drive in the US?

85 mph on State Highway 130 in Texas, which has the highest posted limit in the country and no separate truck limit. Most fleets govern their trucks well below that, so the practical top speed is set by the carrier.

Is there a federal speed limiter requirement for trucks?

No. FMCSA and NHTSA withdrew the proposed heavy-truck speed limiter rule on July 24, 2025. Governor settings are a carrier decision, and many fleets set them in the 60s.

How fast can trucks go in Washington state?

60 mph for trucks over 10,000 pounds, on any road in the state. Cars may run 70 on most rural interstates and 75 on signed segments. Posted lower limits, such as work zones, still apply.

Sources: Insurance Institute for Highway Safety, "Maximum posted speed limits," October 2026; California Vehicle Code sections 22406 and 21655; Idaho House Bill 664 (2026), effective July 1, 2026, as reported by KMVT on June 25, 2026; Oregon Department of Transportation speed zone review (2017) and Oregon truck limits on I-84, as reported by FleetOwner and local media; Michigan, Indiana, Arkansas, Montana and Washington limits per IIHS; Federal Register, 90 FR 34822 (July 24, 2025), withdrawal of the heavy vehicle speed limiter proposal; 49 CFR 383.51(c) (eCFR, October 2026). Current as of October 2026; posted limits change by segment and by law, and the sign on the road always applies. General information, not legal advice.