CDL Combination Vehicles Exam Questions With 100% Correct Answers | Verified | Updated HOW CAN YOU TEST THE TRAILER EMERGENCY BRAKES? - Correct Answer-Place the tractor emergency valve in the emergency position, try to nudge the vehicle forward. COMBINATION VEHICLES ARE USUALLY HEAVIER, LONGER, AND REQUIRE MORE DRIVING SKILL THAN SINGLE COMMERCIAL VEHICLES. - Correct Answer-True WHAT TYPE OF TRAILERS CAN GET STUCK ON RAILROAD-HIGHWAY CROSSINGS? - Correct Answer-Low slung units and single-axle tractor pulling a long trailer with its landing gear set to accommodate a tandem-axle tractor. THE AIR LEAKAGE RATE FOR A COMBINATION VEHICLE (ENGINE OFF, BRAKES OFF) SHOULD BE NO MORE THAN ____ PSI PER MINUTE. - Correct Answer-3AIR LINES ON A COMBINATION VEHICLE ARE OFTEN COLORED TO KEEP THEM FROM GETTING MIXED UP. THE EMERGENCY LINE IS ____; THE SERVICE LINE IS ____. - Correct Answer-Red, Blue THERE ARE TWO THINGS THAT A DRIVER CAN DO TO PREVENT A ROLLOVER. THEY ARE "GO SLOW AROUND CORNERS" AND _____. - Correct Answer-Keep the weight of your cargo as close to the ground as possible. YOU ARE DRIVING A SEMI AND THE TRAILER BREAKS AWAY, PULLING APART THE AIR LINES. YOU EXPECT THE TRAILER BRAKES TO COME ON