Question The most common color of warning signs is: Answers Red. Yellow. Green. Blue. Explanation Most warning signs are diamond-shaped and yellow with black markings. These signs warn drivers about unexpected conditions that may not be readily apparent. Pass your DMV Written Test with flying colors Take me to the cheat sheet Idaho This questions appears in the following tests: Colorado Practice Test 20 Florida Practice Test 30 Hawaii Practice Test 5 Idaho Practice Test 23 Indiana Practice Test 5 Louisiana Practice Test 11 Maine Practice Test 12 Michigan Practice Test 47 Minnesota Practice Test 40 Missouri Practice Test 15 Montana Practice Test 4 Nevada Practice Test 30 New Hampshire Practice Test 33 New Jersey Practice Test 7 New Jersey Practice Test 32 New Jersey Practice Test 16 North Carolina Practice Test 28 North Dakota Practice Test 21 Oklahoma Practice Test 1 Oregon Practice Test 11 Texas Practice Test 26 Utah Practice Test 4 Vermont Practice Test 1 Virginia Practice Test 9 West Virginia Practice Test 17 Wisconsin Practice Test 48