2024 OK CDL Practice Test: Class A - Test 7 Based on 2024 OK CDL Handbook 30. What can the “crack-the-whip” effect do? A Make trucks accelerate. B Make loud noises. C Turn over trailers. D Make trucks decelerate. Grade More 30/30 Progress 0 Errors Restart Grade Grade Class A - Test 7 Back to Test List Class A - Test 6 Class A - Test 8 Challenge Library 12 More OK CDL Practice Tests 8 Class A - Test 8 9 Class B - Test 10 Class B - Test 2 11 Class B - Test 3 12 Class B - Test 4 13 Class B - Test 5 14 Class B - Test 6 15 Class B - Test 7 16 HazMat - Test 17 HazMat - Test 2