State comparison · Updated October 2026
Montana vs. Wyoming Driving Laws (2026)
Montana and Wyoming differ on 5 of 9 topics we track: phone law, learner's permit age, car sales tax, new resident deadline and lane splitting.
A drive from Billings to Cheyenne crosses the state line, and 5 of these laws change on the way. Main routes are I-90 on the Montana side and I-80 in Wyoming; the capitals, Helena and Cheyenne, write the laws for each side.
The largest difference: the state tax on a $30,000 car differs by $1,200. Residents of Missoula who drive to Casper, or the other way around, deal with both sets of rules: Montana's on I-15 and Wyoming's following the state line on I-25. Read the Montana vs Wyoming guide before driving from Billings to Cheyenne.
For a weekend trip from Helena to Cheyenne, keep a helmet and proof of insurance, set navigation before leaving, and expect the same 80 mph top limit after crossing.
| Topic | Montana | Wyoming |
|---|---|---|
| Max speed limit | 80 mph | 80 mph |
| Phone law | No texting ban | Texting ban only |
| Learner's permit age | Permit at 14 | Permit at 15 |
| Car insurance | 25/50/20 | 25/50/20 |
| Car sales tax | None | 4% |
| Car inspection | No regular inspection | No regular inspection |
| New resident deadline | 60 days | Right away |
| Helmet law | Under 18 | Under 18 |
| Lane splitting | Filtering only | Not allowed |
Driving laws side by side: Montana vs Wyoming
Montana vs Wyoming: Montana and Wyoming agree on 80 mph for max speed limit.
Cell phone and texting laws: Montana vs Wyoming
The rule is stricter in Wyoming on phone law, with Montana at no texting ban and Wyoming with texting ban only. Phone use that is fine in Billings cannot be near Cheyenne once you cross.
Driving age and teen license laws: Montana vs Wyoming
Montana is earlier on learner's permit age: Montana with permit at 14 and Wyoming with permit at 15. Teens in Billings taking a trip to Cheyenne are bound by Wyoming's permit rules there.
Owning a car: Montana vs Wyoming
Montana vs Wyoming: Montana and Wyoming match on car insurance: 25/50/20 and No regular inspection for car inspection.
Car sales tax: Montana vs Wyoming
Montana is lower on car sales tax, with Montana with none and Wyoming at 4%. On a $30,000 car, state tax comes to roughly $0 in Montana and $1,200 in Wyoming. Shoppers in Missoula and Casper owe car tax of the state where they register, not the dealer's.
Moving deadlines: Montana vs Wyoming
Montana is longer on new resident deadline, with Montana at 60 days and Wyoming at right away. Households relocating from Missoula into Casper ought to book DMV visits ahead.
Motorcycle: Montana vs Wyoming
Montana vs Wyoming: Wyoming and Montana agree on helmet law: Under 18.
Lane splitting: Montana vs Wyoming
Wyoming is stricter on lane splitting: Montana with filtering only and Wyoming at not allowed. Riders splitting time between Missoula and Casper must change habits at the line.
Moving or buying across the border
- Montana vs Wyoming: relocating from Montana to Wyoming means right away, as soon as you become a resident for the car registration and up to one year for the license switch.
- Moving from Wyoming to Montana: 60 days to register and 60 days to switch licenses.
Montana vs Wyoming: FAQ
Where may you drive faster, Montana or Wyoming?
Wyoming and Montana each allow up to 80 mph.
Is it cheaper to buy a car, Montana or Wyoming?
Montana costs less at the state level (None vs. 4%).
Is a motorcycle helmet mandatory in both Montana and Wyoming?
Montana: Under 18; Wyoming: Under 18.