Watch Now


FTR touts benefits of 33-foot double trailers

Firm suggests 10% savings for fleets with little impact on truckload operations

Every year, it seems, a proposal for allowing 33-foot double trailers on the nation’s roadways resurfaces. Again, this year, a push is being made to influence Congress to make these longer tandem trailers legal.

Industry and safety groups have differing opinions of the trailers. A new market analysis by Noel Perry, truck & transportation expert for FTR Transportation Intelligence, argues the economics of 33-foot doubles – and, based solely on economic reasons, there is a valid case, Perry says.

“Predictably, the proposal has found strong objections from railroads and highway safety groups, and, surprisingly, some truckload TL carriers oppose the idea as well,” Perry notes. “The idea gets strong support from LTL (less-than-truckload) and parcel carriers. The latter two industry segments would be the prime users of the larger combination trailers.”

Perry argues that moving to 33-foot doubles will not impact large segments of the industry and that they will reduce the amount of work required to move goods, and therefore the number of trucks on the road. In fact, according to Perry, the use of 33-foot trailers will likely remain within the domain of those currently using the legal 28-foot combinations – LTL and parcel operations.

“Importantly, [current 28-foot doubles] regulations still restrict doubles operation to 80,000-pound gross weight, so there is only a cubic capacity advantage over conventional single-trailer rigs. Gross weight is still subject to the same federal limitations as single-trailer rigs,” Perry says.

The analyst notes that current 28-foot doubles offer a 4% capacity advantage over a standard 53-foot trailer, allowing LTL and parcel companies the ability to haul more freight to local destinations and then splitting the trailers into single pups for final delivery moves.


The additional length allows an 18% increase in cubic capacity compared to the current 28-foot double operations. The additional length would also increase the cubic capacity advantage relative to 53-foot trailers – a 24.5% increase for 33-foot doubles versus the 4% increase earlier for 28-foot doubles.

— Noel Perry, truck and transportation expert, FTR

“Second, there is also a maneuvering advantage due to the shorter wheel-base of the trailers,” Perry adds. “The rear trailer follows the track of the lead trailer, allowing the rig to turn much more easily than a 53-foot trailer.”

The current proposals call for increasing doubles to 33 feet but leaving the 80,000-pound weight limit intact.

“The change would allow the operators to use two more pallet positions per trailer (i.e., use more cubic capacity while still staying below the gross vehicle weight limit),” Perry says. “The additional length allows an 18% increase in cubic capacity compared to the current 28-foot double operations. The additional length would also increase the cubic capacity advantage relative to 53-foot trailers – a 24.5% increase for 33-foot doubles versus the 4% increase earlier for 28-foot doubles.”

For shippers, the longer trailers would reduce shipping costs. Even the trucking companies will see benefits. Perry notes a 10% savings in overall equipment costs.

“The increase in length will increase new trailer costs by approximately 12%,” he says. “Since there will be no appreciable changes to tractor costs (the biggest cost component), the increase in cost for the entire rig averages out to just 4%. … Against this increase one must factor in the substantial reduction in total rigs required, up to 18% when comparing 28-foot combinations to 33-foot combinations. This decrease is due to the increase in cubic capacity per rig. That gives us a maximum savings in capital of 14% (18% reduction in rigs offset by the 4% increase in rig costs). Since the fleets will not always use the full capacity of the new rigs, the actual number falls to an estimated 10% capital savings.”

Less fuel – about 10% less, Perry says – and labor (15%) would be needed as well. Add in a 10% savings in maintenance due to a reduction in the number of trucks and trailers needed to move the same amount of freight and 10% reduction in total over-the-road operating costs.

All of these cost savings become important due to the growing e-commerce segment.

“This savings is especially relevant today because parcel, and to a lesser extent LTL, is an essential part of the fastest growing supply chain segments, those that serve the exploding online marketplace,” Perry says. “LTL and parcel carriers support the length change proposal because it will simplify their operations and ease difficult driver shortage issues.”

Perry adds the public benefits of 33-foot doubles as well, which include a 10% reduction in emissions, a 10% reduction in wear and tear on already stressed highways, and less congestion.


Brian Straight

Brian Straight leads FreightWaves' Modern Shipper brand as Managing Editor. A journalism graduate of the University of Rhode Island, he has covered everything from a presidential election, to professional sports and Little League baseball, and for more than 10 years has covered trucking and logistics. Before joining FreightWaves, he was previously responsible for the editorial quality and production of Fleet Owner magazine and fleetowner.com. Brian lives in Connecticut with his wife and two kids and spends his time coaching his son’s baseball team, golfing with his daughter, and pursuing his never-ending quest to become a professional bowler. You can reach him at [email protected].