State comparison · Updated October 2026
Montana vs. North Dakota Driving Laws (2026)
Montana and North Dakota part ways on 4 of 9 topics we track: phone law, car insurance, car sales tax and lane splitting.
A drive from Billings to Fargo takes you across the border, and 4 of these laws change on the way. Main routes include I-90 on the Montana side and I-94 in North Dakota; the capitals, Helena and Bismarck, write the laws for their side.
What changes most: the state tax on a $30,000 car differs by $1,500. Drivers based in Missoula who travel to Bismarck, or the other way around, obey both rulebooks: Montana's on I-15 and North Dakota's once they cross on I-29. Read the Montana vs North Dakota guide before driving from Billings and Fargo.
For a quick visit from Helena to Bismarck, pack your documents if you ride, plan the route ahead of time, and watch for the same 80 mph top limit at the border.
| Topic | Montana | North Dakota |
|---|---|---|
| Max speed limit | 80 mph | 80 mph |
| Phone law | No texting ban | Texting ban only |
| Learner's permit age | Permit at 14 | Permit at 14 |
| Car insurance | 25/50/20 | 25/50/25 |
| Car sales tax | None | 5% |
| Car inspection | No regular inspection | No regular inspection |
| New resident deadline | 60 days | 60 days |
| Helmet law | Under 18 | Under 18 |
| Lane splitting | Filtering only | Not allowed |
Driving laws: Montana vs North Dakota
Montana vs North Dakota: North Dakota and Montana match on 80 mph for max speed limit and Permit at 14 for learner's permit age.
Phone law: Montana vs North Dakota
North Dakota is stricter on phone law, with Montana at no texting ban and North Dakota at texting ban only. Phone use that is fine near Billings might not be in Fargo on the other side.
Owning a car: Montana vs North Dakota
Montana vs North Dakota: North Dakota and Montana match on No regular inspection for car inspection and new resident deadline: 60 days.
Car insurance: Montana vs North Dakota
The rule is higher in North Dakota on car insurance, with Montana at 25/50/20 and North Dakota at 25/50/25. Montana is at-fault while North Dakota is no-fault. An insurance policy from Billings has to be switched after a move to Fargo.
Car sales tax: Montana vs North Dakota
The rule is higher in North Dakota on car sales tax, with Montana with none and North Dakota with 5%. For a $30,000 purchase, state tax is about $0 in Montana and $1,500 in North Dakota. Buyers from Missoula or Bismarck owe car tax based on their registration address, not the dealer's.
Motorcycle side by side: Montana vs North Dakota
Montana vs North Dakota: North Dakota and Montana agree on helmet law (Under 18).
Lane splitting laws: Montana vs North Dakota
The rule is more permissive in Montana on lane splitting, with Montana at filtering only and North Dakota with not permitted. Commuters riding between Missoula and Bismarck get no exception.
Moving or buying across the border
- Montana vs North Dakota: moving from Montana to North Dakota gives you 90 days for the car registration and 60 days for a license.
- Moving from North Dakota to Montana: 60 days to register and 60 days to switch licenses.
Montana vs North Dakota: FAQ
Where can you drive faster, Montana or North Dakota?
Both Montana and North Dakota top out at 80 mph.
Is car tax lower — Montana or North Dakota?
Montana costs less at the state level (None vs. 5%).
Do I need a helmet in both Montana and North Dakota?
Montana: Under 18; North Dakota: Under 18.