Both Tank (N) and Doubles/Triples (T) are knowledge-only endorsements (no separate skills test) that meaningfully expand the kinds of jobs available to a Class A CDL holder. They serve different industries entirely, and the right pick depends on your career goals.
Tank (N) — pay and lifestyle
The Tank endorsement opens the door to fuel hauling, food-grade tanker (milk, juice, edible oils), chemical bulk, and dry-bulk pneumatic (cement, sand, plastic pellets). Tanker drivers earn an average of $58,000 to $82,000 annually depending on commodity, region, and whether the role is local, regional, or OTR. Local fuel hauling is among the highest-paying daily-home-time jobs in trucking. The trade-off: longer loading and unloading times, weight-distribution awareness, and constant attention to load surge.
Doubles/Triples (T) — pay and lifestyle
The Doubles/Triples endorsement is the gateway to LTL freight line-haul: FedEx Freight, Old Dominion, Estes, Saia, R+L Carriers, ABF, and the regional LTL networks. Senior LTL line-haul drivers earn $75,000 to $110,000 annually with strong benefits, predictable schedules, and dedicated runs. The trade-off: most LTL line-haul is overnight (dock to dock), and the multi-trailer handling has a learning curve.
Which to add first?
If you want maximum-pay specialty freight and you don't mind the load-management discipline of tankers, add Tank first. If you want predictable schedules, strong benefits, and a long-term career with one of the major LTL carriers, add Doubles/Triples first. Many premium drivers eventually hold both. Drill our Tank study guide and Doubles/Triples study guide before scheduling your knowledge exams.
Cost-of-add
Both endorsements cost essentially nothing beyond the state knowledge-exam fee — typically $5 to $20 per endorsement. Neither requires a TSA check, additional medical certification, or a separate skills test. There's almost no reason not to add both as soon as you've passed your initial Class A.