It varies by state, and also the sort of area you're driving through. School zones may be 25 - 35 Miles Per Hour, whereas, in Texas, you have two-lane roads where you're allowed to run 70 MPH. You'd have to check with each state's individual laws on this.
It varies between states, although only a couple states have differing daytime and nighttime speed limits - Texas and Montana are the ones I'm able to think of offhand. IIRC, both allow speeds of up to 70 on two lane roads.
You need to specify a state. As you're specifying a specific daytime speed limit, you might be referring to Texas, where the answer would be 70 MPH.
65mph is the most you are able to drive on a highway.
75mph on an interstate some can be 80 mph.
Some two lane roads in Texas have a speed limit of 70 MPH.
It varies by jurisdiction. Some such roads in Texas have a speed limit of 70 - other states might not allow a speed higher than 55.
70 mph Minimum is 50 mph
It varies by state.
45
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