Reporter's note: One of the upsides to a long distance road trip is seeing how things are changing in the world of transportation. I'm referring, in this case, to changes being made to semi-truck rigs, tractors and trailers. I'd noticed the addition of trailer skirts several years ago. But on a trip to Seattle I noticed, for the first time, sheet metal looking flaps attached to the rear of cargo trailers-trailer tails.

When I saw the first trailer tail I thought it was a homemade device someone had added to squeeze a few more cubic feet of cargo onto the end of the trailer. Finally I saw a rig, at a rest stop, and understood it was actually a manufactured add-on. When I got back home I did some internet searching and learned the trailer tail has a purpose. In the process of educating myself I learned there's a lot of new technology on semi-trucks, some seen and some not so visible. In the final analysis it's all about fuel efficiency, carbon footprint reductions and, well, about saving money to be more competitive.

One of the premiere trucking companies, and there are many, using new technology to save fuel and be more competitive, is Nussbaum Transportation out of Hudson, IL. Having grown up in Illinois I recalled seeing Nussbaum haulers when I was a kid. I connected with their Vice President of Operations and learned there is a world of changes going on the freight hauling business. Here's what I learned:

Nussbaum Transportation, an industry leader

Brent Nussbaum, current CEO of the company, noted in his blog that the regional trucking business is celebrating its 70th anniversary this year, having been started by his father in Normal, Illinois in 1945. As part of the anniversary the business has painted a number of its trailers with the theme "Celebrating faith and family." They must be doing something right because they are still competing in a very competitive market. And they have garnered many awards from governmental agencies for their work to reduce their carbon footprint and by many trade associations for their innovative approaches to remaining a viable competitor.

From the company website (www.nussbaum.com) I found a contact that I believed could help me figure out the strange contraptions I had seen attached to the rear of trailers. These trailer tails were noted on several companies' trailers during my trip to Seattle. And looking at various transportation related websites, I'd seen the name of Phil Barker, Nussbaum's Vice President of Operations. I caught Barker, between meetings, and he was willing to talk about the 'new world' of trucking.

Trailer tails

When asked about trailer tails, Barker said, "We have them on 600 of our cargo trailers. Basically, they divert the wind past the end of the trailer to reduce drag." At other sites there were scientific explanations of how wind turbulence at the tail of a trailer creates a vacuum that tends to pull the entire rig backwards. The science was a bit beyond my pay grade, but it seemed to make sense. Some readers have likely used the 'pull' from a trailer to get a few extra miles per gallon by following a trailer-way too close for safety, but efficient at times.

There are a number of producers of 'trailer tail' products. But most agree, based on testing, that at 65mph a trailer tail can be expected to deliver about 6.6% in fuel efficiency-that's about eight gallons of fuel saved for every 1000 miles driven. Readers can do the math for a dollar value.

An average cost of a trailer tail, per Barker, is about $1500 installed. He noted operators with large fleets enjoy some economy of scale when purchasing large numbers of trailer tails at one time. He added, "When diesel fuel is averaging $4 a gallon, we figure our payback is about 14 months. When fuel drops to around $2 a gallon, the payback takes a while longer. On a trailer with an expected life of about 10 years there is still a good amount of savings regardless of the price of fuel."

Trailer tails have not been around long enough to have good data about maintenance costs. One figure, from a truck driver's blog, noted, "I drive for a company with about 100 trailers with tails. In two years we've used the tails I encountered only two trailers where the 'pistons' that hold the door in place needed replacing. That seems a pretty good record for the number of miles driven."

Other innovations for fuel savings

Barker listed several other innovations that contribute to fuel economy. Trailer skirts, the long plastic or metal skirts that are attached to the undersides of a trailer, also work to divert air that creates drag when it hits the rear wheels and axles. The skirts became widely adopted by truckers around 2008 and are quite common now. A manufacturer of trailer add-ons noted in a promotional piece, "...together the skirts and tails can deliver 8-12% fuel savings." The different ways in which the two devices are configured account for the variation in savings.

Another innovation, and this seems to be gaining popularity, is larger single tires rather than dual tires on trailers. Barker said, "A wider, single tire has less wind drag and less road friction. The savings are smaller, but still noticeable."

For Nussbaum Transportation, there are more innovations that are less visible. Barker explained that all his company's tractors now are purchased with only one functioning drive axle, though the tractor will typically have two axles at the drive position. He added, "For most of the haling we do on highways, there's no need for double drive axles on tractors. Weight is reduced as well as wind drag, there are fewer moving parts to maintain and the initial purchase cost is less for a new tractor."

Even the lowly mud flap plays a role in fuel efficiency. Barker said, "To reduce road spray during weight conditions, someone designed a porous mud flap. The 'fly swatter design lets the water flow through, causing less water to be thrown up by the wheels. The new design was better for safety with reduced spray but turned out to reduce wind drag under the driver and trailer wheels, improving fuel efficiency." That's a classic case of solving one problem and inadvertently solving another.

Many transport companies now use anti-idling devices and separate power units for heat or air conditioning when a driver is sleeping-both allow fuel savings by allowing the tractor engine to be shut down when the truck is not moving. And many companies, Nussbaum included, are setting fleet wide speed limits to reduce fuel costs and improve safety for truck drivers and other motorists.

Asked "Where does the innovation end?" Barker said, "The impact of some innovations is hard to measure (like the idea of replacing the large mirrors on truck tractors, and the wind drag they create, with digital cameras). If we think an innovation is good for our drivers, our fleet and the environment, we will use it. And, it also depends on the payback time to recoup our initial investment. Fluctuating fuel prices are also a concern, we have a hard time actually calculating a payback when fuel prices vary wildly." He did say there is probably a point at which real economies become negligible through add-on devices. He believes the next step involves totally new designs for tractors and trailers.

What's in the future to improve fuel efficiency?

Answering that question is like asking, "How high is up?" But, there is still innovation going on. Wal-Mart, which logs millions of miles annually with its fleet, unveiled a prototype tractor and trailer configuration at the Mid-America Trucking Show in March, 2014. The prototype tried to incorporate a large number of aerodynamic and mechanical/electrical innovations and involved the combined efforts of several equipment manufaturers. To say the least it's futuristic.

Courtesy Photo

Trailer tails are devices attached to the rear of a semi-trailer to divert wind away from the trailer and reduce backward pull on the trailer. Manufacturers of trailer tails and trailer skirts (the long plastic or metal skirts attached to the bottom of trailers) say the combination of the two devices can reduce fuel use about 8-12%.

Barker, with Nussbaum, said, "I have a photo and article about the Wal-mart prototype on my desk. It's a ways in the future in my opinion, but it is interesting to contemplate the various combinations it uses. A major difference from current equipment is in the power train, which incorporates a turbine engine with a lot of other new but not widely available components."

Trucking has changed and there are more changes in the future. In recent years we've seen obvious changes-tire type, add-ons like skirts and tails. The future changes will likely be less noticeable, but perhaps dramatic as well. It will always be a combination of fuel prices, length of time for an investment to be paid back and government regulation. That formula will be one constant in an otherwise changing industry.