In Michigan it is 45 max on highway and you must go over into the next lane if available and/or possible.
the posted speed limit
The speed limit for vehicles merging onto the highway from an on ramp is typically the same as the posted speed limit for that section of the highway.
The speed limit is 55mph.
The normal speed limit on the highway.
No, it is not legal to exceed the speed limit on a highway under any circumstances.
The off-ramp speed limit on the highway is typically 25-35 mph.
Montana
The speed limit in the fast lane is the same as the speed limit for the road or highway you are driving on.
55 on the highway, and 30 in the city.
It all depends on the type of highway and the speed limit signs.
Whatever the posted speed limit is.