WATERTON LAKES, AB. – Pickup trucks are a key segment of overall vehicles sales across Canada, but where they really rule is in the sprawling plains and foothills of Alberta. It seems that everyone drives a pickup here, but the trucks that are really kings are the heavy-duty models.

While their smaller kin may be more popular with casual truckers, the workhorses are the HDs. They account for about 20% of the national full-size pickup market, with about 62,000 HD trucks sold in this country last year.

Whether getting dirty at a construction site or an oil rig, or flexing their muscles hauling horse trailers or huge fifth-wheel travel trailers, there’s no question the HDs "git ‘er done."

It was, therefore, a logical choice for General Motors to introduce its 2015 HD lineup – the Chevrolet Silverado and GMC Sierra 2500/3500 models – to the media in this beautiful but rugged region of Wild Rose country southwest of Calgary.

True to the working nature of these vehicles, our testers were fitted with a range of loads that would challenge their capabilities – a bed filled with firewood, a huge bale of hay, even a 1,000-kilogram skid-steer loader stuffed into the box.

On the afternoon drive from Calgary to Waterton Lakes National Park, I had the opportunity to check out the Silverado 3500 duallie that was lugging that loader. Despite the hefty weight in the box, the truck purred along at the speed limit without a hint of stress.

The source of its power was a 6.6-litre Duramax diesel V-8, the optional engine choice, coupled to a six-speed Allison automatic transmission. The base engine is a 6.0-litre gasoline-fuelled Vortec V-8, rated at 360 horsepower and 380 lb-ft of torque and paired with a six-speed Hydramatic transmission.

The optional diesel powertrain carries a sizeable price tag – a total of $11,115 – but in the HD world it’s the logical choice. In fact, 60% of all HD trucks sold in this country are oil burners, due in part to the dependability and lower operating costs of a diesel over the lifetime of the truck.

In Chevy and GMC HD applications, the 6.6L diesel generates 397 horsepower and a massive 765 lb-ft of torque, while the gasoline engine is rated at 360 horsepower and 380 lb-ft of torque.

The diesel's massive grunt was obvious when faced with a grade or a request to overtake a slower vehicle. No hesitation, no stumbling – the Allison gearbox instantly downshifted and the engine responded, despite the hefty load in back.

In fact, the only time that load was evident occurred when I had to slow down abruptly for a minivan making an unannounced lane change. The brakes on the Chevy 3500 work fine, but reining in the momentum such a load creates is still demanding.

One feature unique to the Duramax models is an exhaust brake. Activated by a switch on the centre stack, the system uses the variable vanes of the turbocharger to generate back pressure, helping prolong brake life and minimize brake overheating – an especially welcomed feature when descending long, steep grades with a heavy load.

It’s worth noting here that throughout this drive, up and down grades and in highway cruising, this big Chevy truck accomplished it all in a most hushed manner. The changes made to the GM cabs, including triple seals around the door openings, hydraulic body mounts to reduce noise and vibration and inlaid doors that minimize wind noise, all contributed to the quietness of the cabin.

Sitting back, wrapped in luxurious leather seating with a premium audio system cranking out tunes, it was easy to forget I was driving a big, bad-ass HD truck with 1,000 kilograms of construction machinery in the box.

GM reworked the exteriors and cabins of its half-ton lineup for 2014 and much of that freshened look is carried over to the HDs for 2015. Aerodynamics have been improved with rounded edges and tighter gaps that also result in a cleaner look overall.

The Silverado and Sierra grilles and surrounds have been changed, reflecting the design of the 1500 models, and both nameplates feature one-piece chrome bumpers unique to each brand. The hoods and headlamp assemblies are both specific to the HD line.

Some of the features introduced on the 2014 light-duty GM trucks have been carried over to the big boys, including the simple but so effective corner step rear bumper for easier access to the cargo bed.

Upper tie-down points, with up to nine locations, have also been added to the HD models, as has under-rail LED lighting and a dampened tailgate that can be lifted or lowered with ease. For customers preferring a spray-in bed liner, GM now offers that feature factory installed.

Beyond the freshened exteriors, the structure underneath remains familiar. The hydroformed, fully boxed steel frame rides on asymmetrical rear leaf springs and a fully independent front suspension has been tweaked through the use of new bushings for an improved ride.

Customers who plan to use their GM HD rig for hauling or towing will appreciate the new fully integrated cruise control and auto grade braking system, which maintains a more even speed up and own grades.

The integrated trailer brake control is simple to operate and easy to reach on the instrument panel. It displays the gain on the driver information centre.

Drivers will also appreciate the hill start assist system when moving from a standstill on a grade, and likewisefor controlling speed on downgrades.

GM’s StabiliTrack stability control system with integrated trailer sway control is standard on all Silverado and Sierra HD models.

New safety features include a driver alert package with segment exclusive forward collision alert and lane departure warning, plus an available safety alert signal in the driver’s seat. Other features include a rear vision camera, side curtain and seat-mounted side airbags and available front and rear park assist.

Uber-high-end models are now offered in both Chevy and GMC lineups.

The GMC Sierra Denali offers signature features, including distinctive interior and exterior trim, LED headlamps, an eight-inch full-colour customizable driver display, heated and cooled perforated leather front seats with contrasting stitching and 12-way power assist, six-inch chrome step bar and bright sill plates.

Chevy’s top-of-the-line trim level is the High Country HD, the brand’s first premium heavy-duty pickup. It also has distinctive exterior features, including projector headlamps, a chrome grille, body-coloured bumpers, the six-inch step bar and special chrome accents.

It also is fitted with special wheels – 20-inch chrome on the 2500, 18-inch chrome on the 3500 single rear wheel configuration and 17-inch polished aluminum on dual rear-wheel models.

Much like the competitive models from Ford (the F-250/350 King Ranch) and Ram (the Laramie Longhorn), High Country owners will be wrapped in a western-themed, saddle brown cabin with perforated premium leather seats that are heated and cooled, a premium Bose audio system and an eight-inch touch screen featuring Chevrolet MyLink connectivity.

GM is offering truck buyers a wide range of combinations and options so they can tailor their HD truck to fit their specific needs, whether it’s a basic work truck or a fully loaded weekend hauler.

In fact, there are more than 150 configurations available in both the Chevy and GMC lineups, including regular, double and crew cab body styles; a choice for two- or four-wheel drive, 6.5- or 8.0-foot bed lengths, rear axles ratios of 3.73 or 4.10, and gas, diesel or natural gas powertrains.

The latter bi-fuel engine is available on both 2500 and 3500 models and with all three cab styles. The CNG engine also features a full factory warranty.

With this lineup of refreshed, refined trucks, Chevrolet and GMC are poised to claim a bigger share of the competitive HD marketplace.