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: Ohio Practice Test 39 Oregon Practice Test 17 Colorado Practice Test 2 Florida Practice Test 6 Hawaii Practice Test 6 Idaho Practice Test 18 Indiana Practice Test 40 Indiana Practice Test 31 Louisiana Practice Test 38 Maine Practice Test 10 Michigan Practice Test 3 Michigan Practice Test 18 Minnesota Practice Test 34 Missouri Practice Test 13 Montana Practice Test 6 Montana Practice Test 24 Nevada Practice Test 40 New Hampshire Practice Test 5 New Jersey Practice Test 43 North Carolina Practice Test 15 North Dakota Practice Test 14 North Dakota Practice Test 22 Ohio Practice Test 8 Ohio Practice Test 20 Oklahoma Practice Test 19 Oregon Practice Test 14 Texas Practice Test 3 Utah Practice Test 17 Vermont Practice Test 13 Virginia Practice Test 16 West Virginia Practice Test 22 Wisconsin Practice Test 48