Only way to really judge a truck nowadays is to take a real good look inside the cab. The aerodynamic styling of Class 8s that's now almost unremarkable arrived out of the blue back in 1985 with the Kenworth T600, and now a less ballyhooed but nonetheless signification transformation in truck design is well under way. While demand for fuel-sipping trucks has not abated in 20 years, now OEMs, along

Only way to really judge a truck nowadays is to take a real good look inside the cab.

The aerodynamic styling of Class 8s that's now almost unremarkable arrived out of the blue back in 1985 with the Kenworth T600, and now a less ballyhooed but nonetheless signification transformation in truck design is well under way.

While demand for fuel-sipping trucks has not abated in 20 years, now OEMs, along with meeting other changing demands, must also do all they can to help fleets woo and keep truck drivers.

The resulting cab and sleeper upgrades and redesigns aren't visible to passersby but they sure are noticed — and appreciated — by truck drivers

For truck drivers what matters right along with engine and brake performance and ride quality is how well the cab and sleeper contribute to three interrelated human factors: comfort, safety and productivity.

Complicating matters for truck designers and engineers is that nowadays there really is no one physical type of trucker. There are still plenty of hefty male drivers but there are also slighter males and even women to take into account. Thus adjustability of seating and controls is a greater design factor than ever.

Now that the ranks of truck drivers are being drawn from a much wider slice of American society than even 10 years ago, it's also less likely most truckers will like the same interior styling cues and features, which means even trim packages are thought out more than in the past.

To be sure, the days of spec'ing out a hose-it-out “fleet” interior are as gone with the wind as slab-front “flying brick” exteriors.

Like beauty, distinctiveness is in the eye of the beholder. Looking beyond their trademark sheetmetal, OEMs appreciate they can make their trucks stand out to truck buyers and operators alike with a distinctive interior “look” and unique appointments.

Unlike the tractor that astonished drivers dubbed the Anteater on its debut a decade ago, new interiors have not burst onto the trucking scene. They are evolving from what was offered before but changing at a faster clip than ever to keep up with the times.

And just as each OEM offers its own distinctive aerodynamic and “classic” truck models, the overall interior package designed for every nameplate is exclusive and supportive of the individual brand's image.

Indeed, the engineers, designers and marketers of each Class 8 marque have their own “take” on what the interior design of their trucks should deliver for the buyer and user:

  • Kenworth Truck Co., according to assistant chief engineer Jim Bechtold, launched its new interior in mid-2005 specifically “to raise the bar on fit, finish and quality of materials and to enhance ergonomics.”

  • Volvo Trucks North America design director Ruben Perfetti says interior design must take into account that “drivers want a sense of security, including passive and active safety, and visibility to know what is around them and a sense of home.”

  • International Truck and Engine, according to Dave Allendorph, chief designer-heavy vehicles, uses ergonomics to “not just focus on how big drivers are but how they use the truck; what kinds of tasks they are doing while driving.”

  • Mack Trucks' Jerry Warmkessel, marketing product manager-highway products, points out that mastering the “ergonomic triangle,” encompassing the seat, steering column and pedals, is crucial to ensuring maximum flexibility for different drivers.

  • Freightliner Trucks' Jennifer Harris, product marketing manager-on-highway segment, says “interiors are a focal point and in all these decisions we are focused on driveability, productivity and driver retention.”

  • Western Star and Sterling trucks are designed with different buyers in mind, points out Matt Stevenson, manager of product development for the two Freightliner LLC nameplates, but interiors for both marques are designed “to keep costs down while improving ergonomics and helping drivers keep their eyes on the road.”

  • Peterbilt Motors, relates chief engineer Landon Sproull, rolled out its new interior in late ‘05 as a “more upscale design” for driver appeal but “engineered to be cost-effective” for buyer appeal.

Clearly, all OEMs are on the same page, striving to make the insides of their cabs and sleepers as driver-friendly as possible and without sticking it to the bottom line.

Today's Class 8 interior designs are replete with advanced technologies and finished with great attention to detail yet each design ultimately reflects the brand identity of its nameplate and what each OEM thinks is of key importance to truck buyers.


Kenworth's Bechtold describes the OEM's new interior as “very distinctive in some respects and very KW in others” and a hit with buyers — “it's a strong selling point and the response has been overwhelming.”

He says the approach Kenworth took to designing this interior reflects its view of itself as a technology company that is willing to look outside trucking fro its benchmarks. “Early on we started looking a lot at high-end luxury cars to see what makes them stand out and if those attributes could be translated to a truck interior. We wanted to get some of that ‘feel’ in a truck while addressing what's important for the driver to do his or her job.”

Kenworth reached out to material suppliers that had done work for luxury car makes BMW and Lexus. “We wanted to use their technology to improve the fit and finish but also the style of our products,” Bechtold relates.

One of the luxomobile adaptations is a dash top made of Recticel polyurethane that Bechtold says is appealing to the eye and soft to the touch. It also reduces sun glare and windshield reflections thanks to its low-gloss finish and is so durable he says “you can jab a screwdriver in it and hardly see any damage.”

Bechtold says a lot of attention was paid to instrumentation. “We carefully placed the gauges within the ‘driver package,’ added LED backlighting and worked on the fonts [lettering], numbers and symbols used to make them more readable. We've placed warning lights within gauges where they make sense and have warning lights that can be customized as well by use of truck. The new setup uses space better and gets the information across.”

Kenworth did not stop at what the driver sees. Behind the dash, the instruments are linked as part of a “highly multiplexed electrical system developed at DAF, our sister truck-building operation in Europe,” Bechtold notes. “Multiplexing allowed us to simplify wiring behind the dash, then color-code and number it for easier servicing.”

Beyond the dash, other ergonomic developments include a new turn stalk on the steering wheel that adds intermittent wiper controls. Even more impressive is a new “pedal package” design that uses a suspended throttle pedal and complementary brake pedal placement for easier operation. Bechtold notes the suspended pedal gains 2 inches of legroom.

The center console has two 12-volt outlets, a place to stash a cell phone within easy reach of driver and passenger. There's also a new standard CB radio tray built into the header with an eye to accommodating slipseat drivers.

Bechtold also points out that Kenworth has improved its Quiet Cab package to achieve a 20% — equal to one full decibel — reduction in noise levels by placing special sound-deadening materials in key areas.

“Truck interiors,” Bechtold adds, “have to be about fit and finish, durability, ergonomics and safety, all wrapped up in a package appealing to drivers.”


Perfetti of Volvo Trucks North America states that designing a truck always begins with the brand image. “We're very aware of Volvo's European heritage to be concerned with safety and the environment and its Scandinavian cultural appreciation for making things that serve and that last.

“Over time,” he continues, “incorporating those elements becomes automatic and the values they represent are perceived by the customer. But we do make modifications to Volvo's global platform for North American considerations. “

When it comes to interiors that means adjustments for ergonomics based on who's driving trucks here and how those trucks are being used. “As a result, features found in Europe may be taken out of a North American model and other features may be added.”

Perfetti points out that the NAFTA market for trucks is so large that when the truck design process begins “North American needs are addressed from the beginning so we do not end up adapting a global design for use here. For example,” he adds, “we may want a bit more ‘bling’ or fabrics that are more luxurious.”

When it comes to learning what grabs the American driver, Perfetti says he and other Volvo designers and engineers use their CDLs to get out and experience the real world where their products work. “We know what it's like to be jouncing down a bad road or trying to operate switches etc. while under way,” he remarks.

“From my perspective, I think drivers want to climb into the cab and have a sense of security, which includes passive and active safety. They also want to understand what's in front of them but have a sense of ‘home’ as well.”


According to International's Allendorph, the OEM surveyed 1,500 drivers, capturing hundreds of 36-point “body measurement profiles” as they performed various tasks to help make its new ProStar Class 8 tractor [due out next year] as ergonomic and comfortable as possible.

“Our ergonomics team has been very involved n ProStar,” he states. “The key thing is they looked into not just the size of drivers but how they use their trucks.

“In designing the ProStar, we sought to produce a more spacious interior environment, physically and perceptively and to increase storage,” he continues. “We looked at everything from bigger windows to lighter colors to expand the space and then balanced our choices with the rigors of trucking, which gets things get dirty.”

Allendorph says the ProStar research was eminently practical. “To get storage right, we polled drivers on what they take with them, including personal items like laptops etc. Then we packed that stuff in each time [we reviewed the design]. We looked at what we and the competition were doing, and kept working at how much stuff we could get in.”

As a result, he says the ProStar will boast a “variety of storage spaces from slots to drawers to pockets, and these will be as user-definable as possible. We keep in mind that while a truck is finite in capacity, it's used by an almost infinite audience of customers.”

Ergonomic improvements on the new model touted by Allendorph include an integrated driver information center positioned in the wing panel of the dashboard. “This will integrate all the different truck computer systems by presenting data to drivers with one graphic interface.”

Allendorph says lighting — “forward, rearward, interior” — is crucial to making a operating a truck safe, comfortable and appealing. “You have to pay attention to even esoteric things like the lighting in the sleeper because it all contributes to making the truck a great place to work and live in for the driver.”

While seeking to make the cab appealing to a range of drivers, Allendorph admits there are limits. “You want to keep things as straightforward as possible to keep costs in line [with buyer expectations].”

He adds that International's design effort is aimed at “wanting the driver to be attracted by the truck's exterior and then have them find that everything inside fits them, is within reach and can be adjusted as needed.”


Mack's Warmkessel says development of the Pinnacle highway model put a heavy focus on meeting driver needs.

“The biggest change to our highway truck interior was making the day cab version four inches deeper,” he points out. “This gives more leg and belly room and boosts the seat-angle recline to more than 20% so it's more comfortable for more drivers, especially the taller ones.”

While that's the biggest single change, Warmkessel says it came part and parcel with Mack's attention to “positioning the ergonomic triangle [seat, steering wheel, controls] to accommodate more than just the 95th-percentile person. Today, trucks have to fit the traditional driver as well as those who are smaller or slighter.”

He says a key ergonomic improvement is the Pinnacle's “cockpit style” dash that boasts a new primary gauge cluster and space for up to 25 switches. “The wrap-around dash helps that 98th percentile person lean in and make the adjustments they need.”

There is a new suspended pedal arrangement that allows the operator “to move easily from throttle to brake, like in a car and the adjustable steering column no longer has detents, so it can be placed exactly where the driver wants it.”

Warmkessel says other big improvements aimed at driver satisfaction include increased firewall insulation “to help reduce the noise level to what we believe is an industry standard”; interior lighting that is “best in class”; and a HVAC system with 15% larger a/c outlets “for a 15% boost in the coldness of the air and its volume.”

He says these and other features “add up to an interior environment that promotes safety, eases service and provides a level of comfort that's sure to help attract and retain drivers.”


Freightliner's Harris says all the attention being paid to the inside of trucks can be summed up as getting the “HMI — the human/machine interface — right so that drivers can be both productive comfortable.

“Really, there are pretty substantial changes being made to improve truck interiors,” she continues. “That's certainly the case with all Freightliner models.”

Harris points out that “just last year we went to a new under-bunk storage system for sleepers; added an upgraded inner-spring mattress that reduces ‘bounce’ by 20% to benefit team drivers; and we introduced a premium mattress option that is more bed-like for drivers who want more.”

Sleepers for Century, Columbia and Coronado models also were treated to an “extreme insulation package” that Harris says affords better sound quality and improved temperature control to help decrease the idling time needed to maintain a comfortable temperature. She notes that ant-idling devices, be they gen sets or battery-powered systems, are a “hot button” for fleets concerned about fuel economy and state and local noise regs.

“Among the latest improvements,” Harris relates, “is a new steering column design on Coronado, Columbia and Century Class trucks that entered production in August. It's a tilt/telescopic unit with a wide range of adjustment. It uses a gas spring so it's not dependent on air being available to make entering and exiting the cab easier when the engine is off. It accommodates larger drivers but offers great adjustability for smaller drivers.”

Harris says helping seat drivers well while keeping cost down was the inspiration for the proprietary EzyRider seat the OEM developed with Sears Seating.

“When we developed this there was no high-back air seat with the features fleets wanted available at a low enough cost,” she relates. “The EzyRider features a wider seat cushion and seatback as well as longer armrests to ensure a very comfortable seating position. It also has a parallel bar instead of a scissor suspension to reduce side-to-side rocking.”


Western Star/Sterling's Stevenson says that the two distinct nameplates appeal to different sets of buyers but all models must have driver appeal and must be developed with cost in mind “because the trucks must ultimately make good business sense.”

As for designing for drivers, he says “the overall goal is to help keep the driver's eye on the road and improve ergonomics for comfort as well.”

Stevenson notes that Western Stars are fitted with an automotive-style “soft touch” dash. “We look at automotive materials but there has to be a balance struck between car and truck styling.

“Both Western Star and Sterling models are designed with the idea of putting everything in better reach of the driver. I think in the near term we will see GPS, communications and radios etc. being placed into one centralized place to make it easier for the driver to access these features.

“The goal is to help drivers feel comfortable, safe and productive at work,” he adds. “There really is no such thing as a stripped-down interior anymore — not if you want anyone to drive the truck. Drivers expect the best.”


Peterbilt's Sproull figures a truck's interior design should deliver “practical luxury” by making the most of driver ergonomics to boost both comfort and productivity

He argues “drivers are becoming more sophisticated and are expecting a higher-quality interior. At the same time, when driver turnover is over 100%, a fleet can justify buying a more expensive cab and sleeper — yet we still must design it to be as low cost as possible. The challenge is reaching the right audience without overstepping the bounds.

“The new interior we launched in ‘05 was a departure for us,” he continues. “We bench-marked luxury car makers and from there we designed an upscale but cost-effective interior.”

Sproull says a central goal of the new interior was to improve fit and finish to reduce squeaks and rattles, “because as cabs get quieter, more of these noises start to show up.”

He says that Peterbilt “invested in tooling up soft and hard trim items that are dimensionally stable so there is little variance. This makes for better fit and finish and that what eliminates squeaks and rattles.”

Another big change was to goose up the airflow from the HVAC system “by 20% for better side-window defrosting and faster heating and cooling — by 20%.”

Outward visibility was improved by lowering the “beltline” of the door windows by two inches in the front and one inch in the rear, and by changing the contour of the dash.

Sproull notes that Peterbilt will offer a 63-in. sleeper with many of the premium amenities found in its 70-in. model so “our customers can get luxury in a smaller package to help them offset the higher cost of trucks due to the ‘07 emissions regs.”

Despite their different approaches and distinctive end results, the ultimate goal for all Class 8 truck builders is to design interiors that help make their trucks a destination — the place where truckers would want to spend time making their living.

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