CDL Doubles/Triples case studies
CDL Doubles/Triples · Put your knowledge to work in context.
The Doubles/Triples (T) endorsement is added to a Commercial Driver's License to authorize operating a combination of two or three trailers - the configuration used by less-than-truckload carriers, package and parcel linehaul runs, and fuel or beverage operations that pull pup trailers. It is a knowledge endorsement, not a separate license: you must already hold (or be working toward) a CDL, and your state licensing agency determines what else it wants to see before the endorsement appears on your record. The CDL Doubles/Triples case studies are 5 cases and about 3,869 words.
1The Right Turn That Fits on Paper
You are driving a three-axle tractor pulling two 28-foot pups, 74 feet bumper to bumper, northbound at 0600 on a five-lane arterial posted 40 mph. You need the right turn onto a two-lane street.
782 words, about 4 min2Coupling a Converter Dolly in a Sloped Yard
You are building a set in a distribution yard with a noticeable slope. The lead pup is loaded and its rear pintle hook sits at about 32 inches.
820 words, about 4 min30430 Pre-trip: Five Findings, One Clock
It is 0430 and 34 degrees. You are doing a pre-trip on a triple set you did not build, three loaded 28-foot pups, and dispatch wants it rolling at 0500.
777 words, about 4 min4Leak Test Math on an Eight-Glad-Hand Set
You are assigned a triple set: tractor plus three 28-foot pups, eight glad hands in total. In the yard the system is charged to 112 psi, engine off, wheels chocked, trailer air supply valve pushed in.
742 words, about 4 min5Empty Tail Trailer at 58 mph
You are pulling a set of triples on an interstate: three 28-foot pups, the first two scaled at about 12,000 lb each and the last one empty. The wind is from the right at 25 mph, gusting to 35.
748 words, about 4 min