Assuming the roads are safe and clear, how fast can you legally go? Well, it depends on where you are. 

In an urban district, the speed limit's 30mph. On unpaved roads, the speed limit's 35mph. Paved country roads usually have a speed limit of 45mph. Specific sections of highway might have a speed limit of 65 or 70mph, but most other areas, including highways not otherwise posted, have a speed limit of 55mph.

Other than that, you're likely to see speed limit signs indicating a wide range of limits based on a variety of conditions, like constructions zones, school zones, or half-finished-then-abandoned bridge zones. Just remember to never drive faster than the speed limit—and slower still if conditions are poor—so that you don't go ramming into the rear end of a hatchback or flying off into a swamp.