First, a small apology to an unidentified HGV driver: on my way to the headquarters of Mercedes-Benz UK last Friday morning, I might have inadvertently cut you up. While negotiating the incessant, anonymous web of roundabouts in Milton Keynes, I found myself in the wrong lane and needed to slip to the left in order to exit at the correct junction.

There would have been room for the lane change but at the moment that I started to pull across, a set of traffic lights on the roundabout blinked onto red and everyone ahead of me had to pull up pretty quickly. My sudden appearance in the inside lane meant the space the following lorry driver had to bring his heavy load to a halt was reduced by a few metres. Mea culpa, and as he gave me a shrill blast on the horn to voice his displeasure I shamefully slunk low in my Peugeot's seat.

I can say with some confidence that I won't make the same mistake again, because during my day at Mercedes I enjoyed a passenger ride in the latest version of the German firm's mighty Actros heavy-duty truck, and thus got an appreciation of what life is like for a long-distance lorry driver.

It might be stating the obvious, but it is impossible to not be awed by the size of the Actros. Apparently you could fit a whole Smart car inside the cabin (sadly Merc wasn't willing to let us put that theory to the test). The whole truck can be configured in a variety of cab sizes and specifications, but to someone more used to city cars and hatchbacks, they seem to range from merely 'big' through to 'gigantic'.

Even the key is huge. Forget those show-offs who flash their 911 or M3 key fobs in the pub; the Actros comes with a remote control key that's the size of a mobile phone. It doesn't just start the vehicle, but can be configured to provide tyre pressures, suspension levels and a host of other important technical information, even if you're eating breakfast in the Little Chef and your truck is in the car park.

The vastness continues when you clamber up the aluminium steps into the high-roofed cabin. I've lived in smaller apartments: the driver and passenger seats are practically on different continents, and behind both there's a decent-sized bed, with the option of an upper bunk too. Unlike many rigs, the new Actros comes with a completely flat cabin floor. This has been enabled by compact drivetrain packaging, and it means there's more space for a multitude of drawers, cubby holes and flat surfaces to make the HGV driver's life on the road as comfortable as possible. Mind you, the ultra-supple suspension seats take some getting used to, and until you learn to master the rocking motion it's easy to precariously wobble around like a Weeble.

Merc's commercial vehicles press guru Simon Wood was my chauffeur for a quick trip around Milton Keynes, and I've never been more envious that my driving licence lacks the necessary big-rig qualifications. He made driving Actros look remarkably fuss-free; the 12-speed automated gearbox can be left to look after most of the task of speeding up and slowing down, and although there isn't a surplus of spare room on Britain's roads, the truck's design is mainly straight lines, so its quite easy to sense where all the edges are. The layout of the controls brings a whole new meaning to the phrase 'driver-focused', and visibility is second-to-none thanks to the massive mirrors.

The Actros's ride felt very firm during our journey. The rig's air suspension is set up to haul 30-tonne loads, not travel without a trailer, because a truck without a trailer is a truck that isn't making money for the haulage firm that runs it. Consequently every speed bump jolts through the cabin at 5mph when the rig is unhitched, but apparently when a loaded trailer is attached, it wafts over the bumps with all the poise of an S-class.

With the cabin well over a metre off the ground, you get a different perspective on the world. Maintaining smooth momentum is key for the big rig driver carrying a load, and the fact you can see much further down the road makes it possible to plan a long way ahead (except when errant motoring hacks are in the vicinity, of course).

Although driver comfort and hauling ability are important factors in the appeal of the Actros, the over-riding consideration for haulage contractors is a tractor unit's ability to make money. Or, at least, not burn through quite so much potential profit via fuel costs – an increasingly painful headache of hauliers. Especially when you consider your new Actros can be specified with a diesel tank volume of more than 1400 litres.

The Euro 6-compliant six-cylinder engine in the Actros is said to be four per cent more efficient than the previous powerplant. If a haulage company is operating 20 trucks across its fleet, the fuel bill savings during a year could run into tens of thousands of pounds. There's also a new system called Predictive Powertrain Control that uses GPS to read the topography of the road ahead and optimises the automatic gear changes in anticipation of hills, saving more precious fuel.

So with its sophisticated technology, excellent ergonomics, cavernous storage and monstrous hauling capabilities, the Actros would probably win most games of Mercedes Top Trumps, not least because it packs maximum torque of 1844lb ft and maximum power of 503bhp when equipped with the most powerful engine option.

Oh, and the three-pointed star on the front can be illuminated at the flick of a switch. Even I'd be able to see that looming in my rear-view mirror…