Engineers don't buy a lot of trucks. That's why Freightliner relied heavily on customer input in building Cascadia. It's the truck the users told the engineers they wanted. Left to their own devices, the clever folks over at Corp III – Freightliner's design and engineering complex – can come up with some pretty interesting little science projects. But if the customers don't want 'em or don't like 'em, they're not going to sell.

To its credit, Freightliner took the customers' wish lists seriously. They started with few assumptions, save for the proven P3 chassis (if it ain't broke, don't fix it), and left few stones unturned in developing this machine. The company invested more than $400 million in engineering and product validation, and over a million man-hours of development and testing. If our 400-mile test ride is any indication, Freightliner has invested wisely.

Back in 1988 when Freightliner rolled out the FLD line, computer-aided design, computational fluid dynamics, accelerated testing and laser vibrometers were just twinkles in engineers' eyes. While the FLD was the state of the art at the time, it can't hold a candle to this one. Advances in engineering and materials science have given the bright people at Corp III a lot to work with, and their efforts have produced quite the truck – in fact, it seems a little oxymoronic to call the thing a truck.

Driver comfort and low life-cycle costs topped the list of objectives.

For example, a tremendous amount of research was done to reduce cab noise levels, and the results are impressive. Cruising at 1,300 rpm at 62 mph, my meter read 66 dB(A). My Ford Taurus – not a notoriously quiet car – cruises at 58 dB. For the record, I recorded Cascadia at 67 dB in a hard pull (1,300 rpm) and at 70 dB with the engine brake running at 2,000 rpm and the fan on.

If it's not the quietest truck on the road, Cascadia shares first place with another recently launched Class 8, the International ProStar. Steve Sturgess and I tested ProStar a week before I drove the Cascadia, and because we used different sound meters, we can't offer conclusive proof, except to say the numbers were nearly identical. Compare my numbers with Steve's measurements in his review of the ProStar on page 82.

SOUND ATTENUATION

The key to the incredible improvement in cab noise levels, according to Matt Markstaller, manager of product validation, is reducing or eliminating the offensive noise, and leaving the correct level of the right noise.

For example, human speech is fairly high-frequency sound, so when the driver environment is cluttered with a lot of other high-frequency sounds, speech becomes difficult. On the other hand, low-frequency sounds and vibrations from air suspensions, tire and engine noise or frame beaming can actually improve the ambient sound in the cab. It's an exercise in tuning the cab so it sounds good.

The science is to the point now where, with the use of spectrum analyzers and past experience, certain crankshaft vibrations common to all in-line six-cylinder engines at a particular rpm can be identified and filtered out so engineers can ignore that in searching for other noise sources.

Markstaller recalls a previous noise elimination challenge that eventually pointed to a washer on the fuel tank mounting clips. It rattled, sending vibrations into the frame, producing a squeak inside the cab. You won't hear that noise in Cascadia, but you will notice the fuel tank mounting bracket is just a little different than on previous models.

Larger and more obvious design changes aimed at noise mitigation include improved engine mounts, a hydraulic clutch linkage, and a superb insulation package. Sculpting lines on the cab sides – and particularly on the back of the cab – reduce low-frequency vibration of the body panels. They can, under some circumstances, act like big speakers, producing a unique low-frequency rumble. That's virtually eliminated in the Cascadia.

The money spent on sound attenuation was significant, and in my opinion, money well spent.

CUSTOMER-DRIVEN DEMANDS

Also tall on the list of customer requests was a larger cab. Cascadia delivers here too. While researching the design criteria, Freightliner discovered that drivers are, on average, about 17 percent heavier than they were when the FLD hit the street. In 1988, the average driver weighed 190 pounds. In 2001, the average weight was 215 pounds. Today, an average driver tips the scales at 230 pounds.

As a result, Cascadia's cab is 20 percent bigger, allowing for a larger door opening and larger seats – with more room between them.

While other OEs have been leaning toward sexier, automotive styling, Freightliner has instead been focusing on what customers want – going decidedly against the grain, in some instances.

The two-piece roped-in windshield, for example, is less expensive to replace and requires less than 30 minutes of labor, as opposed to the single-sheet bonded windshield that is more expensive and requires many hours for the adhesive to set. Chris Hofmann, director of product strategy, told HDT that while the bonded windshield may offer a slight aerodynamic advantage, customers made it very clear they weren't prepared to lose a day's work to drying glue.

The Cascadia's dash panels have gone back to easier-to-use exposed fasteners. Customers say hidden fasteners don't thwart drivers who want into the dash, and they slow down techs. The dash panels often came out the worse for a battle with the screwdriver. In the end, practicality trumped style.

Says Hofmann, "We know what we like, and the customers know what they like. Who are we to say no? Engineers and stylists don't buy a lot of trucks."

The list of engineered improvements is a long one, but among the notables:

- The dash is fully multiplexed, so all the gauges and control switches are literally plug-and-play – they pop out and snap in, and all wiring is color- and number-coded.

- The battery box has been moved from between the frame rails at the back of the cab to the driver's side door-step position. Shorter cables mean less voltage drop, even though the frame-rail position produces less battery-wrecking vibration.

- The cab extenders are much shorter, though equally effective aerodynamically, as the traditionally larger ones. They're less prone to damage, and have breakaway mounts in case a driver still manages to knock one against a trailer.

- The HVAC system boasts improved air flow and greater control, with six cab ducts and an eight-position fan switch. The rear heater core and fan motor is tucked under the cabinet behind the driver, not under the bunk, leaving more room for storage.

From a driver comfort point of view, perhaps the greatest improvement in Cascadia is the dramatic reduction in fan-on time and fan noise. A 1,625-square-inch radiator provides enough cooling capacity that Freightliner was able to lower the dependence on fan-induced air flow to provide cooling. The result is spectacular.

"Our EPA '07 design achieves the desired cooling without the fan," Hofmann told us. "Our bigger engine-mounted radiator. combined with under hood air flow design developed in our wind tunnel, ensures all the air going under hood is used most efficiently for cooling and nothing else."

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FUNCTION BEGETS FORM

Under-hood air baffles contribute greatly to improved air flow, and mitigate the aero loses associated with the larger hood opening.

"Cascadia's appearance is counter-intuitive," admits Markstaller. "It may look chunky and less-than-aerodynamic to the eye, but wind tunnel testing tells us otherwise. It's all about how we channel the air through the rad and under the hood. It's much better aerodynamically than the visual cues might suggest."

The big gain is silence. It's a real plus not having the fan roaring away under the hood – even with the A/C on. When the fan did come on, it was barely perceptible. In fact, there was less than a two dB difference in cab noise levels with and without the fan. Freightliner also gets away with a much less aggressive fan. So, with reduced fan-on time and a fan that draws less horsepower, there are fuel savings to be had here too. Big fans can draw as much as 40 horsepower in some instances.

Clearly, excessive fan-on time isn't something the industry will have to get used to. Freightliner has solved that problem rather deftly. It remains to be seen whether the others will follow its example.

Cascadia's mirrors and glass surfaces got a lot of design attention as well. First, the mirrors are smaller than some, but the visibility is exceptional. They're door-mounted and positioned lower than many mirrors, and they're set back slightly from the A pillar. This, Freightliner say, lessens aerodynamic drag, while improving airflow around the windshield and side windows. The result, they promise, is windows and mirror glass that won't accumulate dirt.

Engineers tested this using a spray of water in the wind tunnel containing fluorescent dye, recorded under UV lighting so the path of the water rivulets could be traced and recorded. Modifications we made to the design, optimizing water flow to minimize the adherence of dirty water to the glass. That improvement won't go unnoticed by drivers.

And so goes the list. Some big dramatic changes in appearance, lots of smaller tweaks asked for by customers, and a whole lot of engineering and design expertise brought to bear on the challenge. The truck is pretty well 2010-ready too, so the next hurdle won't hurt so much.

STEERING AND GEARING

Twenty miles of stop-and-go traffic is enough to annoy anyone, but that's Portland, Ore., for you at 4 p.m. Surprisingly, I was still smiling when I hauled it into the Flying J at Troutdale for an axle-weight and a coffee on the first leg of the trip. The sweet throttle response of the Cat and the tight gear steps of the Eaton Fuller 18-speed made all that shifting fun. The gear stick comes straight up through the floor, and tips left toward the driver, making it a nice, tight, easy-to-use shifter.

The hydraulic clutch linkage took a bit of getting used to. It doesn't have quite the same engagement feel as a direct-linked clutch pedal, so it feels a little dead at engagement. Drivers will get used to it quickly, and come to like it. The engineers tell me the hydraulic linkage keeps a lot of unpleasant noise and vibration out of the cab.

Armed with my scale ticket and a really nasty cup of coffee, I hit I-84 west, headed for Biggs where I'd turn south on U.S. 97, headed for Bend. As Interstate highways go, that stretch of I-84 has to be among the nicest in the land, with loads of twists and turns and modest grades. The Cat made short work of the hills, and the TRW steering gear, mated with the one-and-a-half-leaf front suspension, took the curves like a cat with sticky feet.

Rack and pinion steering is an option on Cascadia, but this truck wasn't so equipped. I drove a different one the following day with the rack-and-pinion setup, and brother, let me tell you, no matter what it costs, it's worth it. Cascadia was a dream to steer with the TRW setup, and something close to ecstatic with the rack-and-pinion gear. If you like to drive – really get in there and work the truck – Cascadia with rack-and-pinion steering will make you very, very happy.

Even in the last moments of the drive the following day, a little tired and facing Portland's stupid traffic, I was looking forward to the urban portion of the test so I could shift more gears and turn more corners. I like to drive, and I found this truck very satisfying.

After a pleasant dinner at Cousins Restaurant in The Dalles – a great place to eat if you're ever up that way (trucks can park on the shoulder in front of the place) – I hit the big hill at the top of U.S. 97. It's a long climb but the Cat wasn't even sweating. Upshifting in a climb can be risky, but not with the C15. Notably, during the climb, the fan never came on. In fact, I hardly ever heard the fan come on.

It was dark by the time I'd hit the top of the hill at Biggs, so without the usual distractions of the splendid Oregon scenery, I was free to focus on how the truck felt and sounded. While the noise damping job they'd done on Cascadia was admirable, they left enough room for a bit of engine noise to infiltrate the cab, and frankly, that's just fine. Various stretches of 97 get pretty hilly, so managing the gears was a priority. A little engine noise is helpful in this regard.

A note or two about the headlights is in order here. The low beams were a little weak at the knees, but the high beams were spectacular. I don't ever recall that kind of nighttime visibility before. Al Pearson, director of vehicle testing, told me it might have been an adjustment issue, because I found the low beams just a little too tight to the front of the truck for my taste. I suppose I could have adjusted them – I'm told tools are not required for that task – but there was nowhere to pull over on 97.

Visibility in the Cascadia is remarkable. Big windows, fine mirrors, low hood crown. What's not to like?

I spent the night in the truck in a Wal-Mart parking lot in Bend. I like to sleep in a new truck to see where I bump my head in the dark, or how hard it is to turn off the reading lights at nap time. The Cascadia sleeper gets full marks for convenience and comfort, though the sliding windows in the sleeper still need a little work. The latches are awkward, and require two hands to get them open.

The fridge sits about 16 inches off the floor, making it easy to reach into without bending over. The bunk lighting sets a nice mood, and it's fine for reading. The occupant of the upper bunk has just as much room as the lower, though the mattress is some 10 inches narrower. The climb up there isn't difficult, but the first step is a little tall. Lighting up there is good too, and so is the air circulation in the whole bunk area.

Getting in and out of the driver's seat is a cinch, though I'd omit the cup holder mounted on the floor aft of the gear shifter. I tripped over that a couple of times. The position of the gear shifter didn't obstruct egress from the seat at all. And with 21 inches between the armrests, and 38.5 inches between the cabinets in the bunk, there's no shortage of room inside the cab and sleeper.

Cascadia is a truck that drivers will take to. It's big and roomy, it's quiet, and it rides and handles like a charm.

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From a maintenance perspective, I didn't notice anything that appeared to be downright difficult, but the cab fairings will get in the way of some tasks. Engine work could be a chore on the Cat engines. They're packed pretty tight under the hood, while the Series 60 I drove with the rack-and-pinion steering set-up had a little more air between the frame rails. DPF maintenance shouldn't be much of an issue, considering how infrequently it's required, and Cascadia's DPF is frame-mounted under the bunk, easy enough to get at.

The sophisticated electronics will demand qualified technicians. Cutting into the wrong wire in a multiplexed electrical system can create problems. Its modular design lends itself to replacement of defective electronics rather than repair, so what you save in shop labor, you may incur in parts inventory. Just my guess.

CONCLUSIONS

Buyers who remain emotionally detached from the asset acquisition process will appreciate Cascadia's engineered improvements and inherent operating economy. Even if the sticker price is a little higher than the competition's, it won't take long to realize the lower life-cycle costs and high driver acceptance rates. I think Cascadia will prove to be a truck that earns its keep.

Image-conscience owner-operators may balk, initially, at its slightly boxy appearance, but those that buy with their heads rather than their loins will appreciate the benefits of this truck. It's designed for comfort, efficiency, and low cost of operation. The cab is unbelievably quiet, the ride is terrific, and there's a ton of room in the cab. It was designed to keep maintenance and repair costs to a minimum while offering substantial fuel savings through its wind-tunnel proven aerodynamic superiority.

As for the big radiator, it's likely that we'll see higher displacement engines come our way in 2010 as a means of complying with even stricter emissions reductions. The big radiator could be a necessity in a few years. In the meantime, given the choice between Cascadia's large-ish rad, and the near-constant roar of a very aggressive fan behind a smaller rad, I'll take the big hole in the nose any day.

Test Vehicle Specs

Tractor Freightliner Cascadia 72-in raised roof sleeper cab

Engine Caterpillar C15 ACERT 475 hp / 1,650 pounds-feet

Clutch Eaton Fuller 15.5-in. Solo Ceramic (hydraulic linkage)

Transmission Eaton Fuller RTLO-18918B 18-speed

Drive Axles AAC MBA ART400-4 Ratio 3.42

Rear Suspension

Freightliner Air-Liner 40,000#

Front Axle AAC AF13.3 13,300#

Front Suspension 1 1 / 2 leaf 12,000#

Steering TRW Integral gear

Foundation Brakes

Front Meritor 15X4 Q+ drum

Rear Meritor 16.5X7 Q+ drum

ABS WABCO 4S/4M Anti-lock braking system

Wheels Accuride 22.5 x 8.25

Tires

Front Michelin XZA3 275/80R22.5

Rear Michelin XDA3 275/80R22.5

Fuel Tanks 100 gallon/378 L aluminum X 2

Cab Aluminum, 125-in BBC, 3-piece composite hood

Cab Interior Premium, Two-tone charcoal

Seats National NTS 5E-P3 Elite Highback (proprietary)

Cascadia By Numbers

Wheelbase 239"

Curb weight (full fuel) 20,500 lb

Steer 11,880 lb

Drives 8,620 lb

Turning circle 33.7' curb-to-curb

Closest sight to ground apx 13' (16.6' SAE)

Cab

Shoulder width 76"

Height at standup point 94"

Seat to ceiling min 44" max 56"

Legroom min 14" max 21"

Floor height 49"

Door opening (post to post) 34"

Sleeper

Walkthrough

21" (at armrests)

27" (at seat sides)

Width at cabinets 38.5"

Height at bunk 98"

Bunk to ceiling (lower) 37"

Bunk width

lower 40"

upper 30"

Length 80"

Cab noise

Cruise 1,300 rpm 66 dB(A)

Hard pull (1,300) 67 dB

Engine brake (2000) 70 dB (fan on)

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