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 11 Florida Practice Test 22 Florida Practice Test 16 Hawaii Practice Test 20 Idaho Practice Test 17 Idaho Practice Test 30 Indiana Practice Test 9 Indiana Practice Test 31 Louisiana Practice Test 20 Louisiana Practice Test 39 Maine Practice Test 32 Michigan Practice Test 41 Michigan Practice Test 9 Minnesota Practice Test 16 Minnesota Practice Test 31 Missouri Practice Test 24 Montana Practice Test 32 Montana Practice Test 1 Nevada Practice Test 27 Nevada Practice Test 10 New Hampshire Practice Test 37 New Jersey Practice Test 48 New Jersey Practice Test 30 North Carolina Practice Test 17 North Dakota Practice Test 17 Ohio Practice Test 15 Oklahoma Practice Test 8 Oregon Practice Test 20 Oregon Practice Test 30 Texas Practice Test 23 Utah Practice Test 22 Vermont Practice Test 14 Virginia Practice Test 26 West Virginia Practice Test 1 Wisconsin Practice Test 50