Question State and local authorities: Answers Must post the same speed limit for all roads that are similar to one another. May adjust statewide speed limits by posting speed limit signs. Do not have the authority to post varying speed limits. Must never post a speed limit lower than 35 miles per hour. Explanation Regardless of standard speed limit maximums set by law, state and local authorities may adjust speed limits in specific areas by posting speed limit signs. When it is reasonable and prudent, follow the posted speed limit. Pass your DMV Written Test with flying colors Take me to the cheat sheet Idaho This questions appears in the following tests: Idaho Practice Test 27 Idaho Practice Test 20