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.