Mercedes Night View Assist Plus Test

Look at the Stelvio Pass from any direction and you get an inkling of the fun to be had from its 48 hairpin bends. Drive it and you'll reset your parameters for what makes a great road. No surprises that this ribbon of tarmac covering a one-and-a-bit mile vertical ascent in the Italian Alps has been voted Europe's greatest driver's road.

But it's not just a hedonist's paradise; there are its drops (steep) and concrete walls (solid) that will punish even the smallest misjudgement with at best badly scraped paintwork, at worst the unthinkable. And that's during the day. At night it's deserted, a testament to the dangers inherent on such a challenging piece of road. The perfect place to stage a road test in the dark with no lights, then.

It sounds foolhardy. And it would be if we didn't have a very powerful weapon standing between us and certain disaster: Mercedes-Benz's Night View Assist Plus. The system, a $1750 option that's available on the new E-Class, S-Class and CLS has been designed to work as a supplement to regular headlamps. Unlike the far infra-red of the systems used by the police that simply pick up the heat of humans and vehicles, near infra-red technology offers a much more comprehensive picture. Lights at the front of the car throw out a beam that's invisible to the naked eye. However, it enables the camera located in front of the rear view mirror to 'see' enough to present the driver with a comprehensive black and white picture of the road.

It meant that even with the powerful headlamps on our new E-Class test car covered with masking tape, there was still a clear picture of the road ahead from the driver's seat. But would it be good enough to drive by? Mercedes had also lent us a C-Class to ensure the road ahead was free of traffic so every base was covered. Almost.

As a safety feature Night View Assist Plus doesn't start working until the car's doing 10 mph. So we had to start with at least 165 feet of straight road to allow the system to kick in before one of the Stelvio's notorious hairpins. With a crackled all clear over the radio, I slot the big Merc into Drive and plunge into the night. And what a leap of faith it is. Thankfully in less than two seconds the black and white screen in front of me flickers into life and I have a clear image of the road ahead.