Winter actually starts in autumn at Arvidsjaur in northern Sweden and nearby Arjeplog: as early as October, the minimum daily temperature regularly drops below zero degrees Celsius, and this continues right through to May. On average, the weather station reports 186 frost days a year, with an annual average temperature of almost exactly zero degrees.

Heavy downfalls are likewise the norm – those looking for snow in the winter months have come to the right place. And once on the ground, the snow stays there: generally the daily highs do not start climbing above zero degrees again until April onwards.

The two towns on the 65th and 66th parallel are situated just below the Arctic Circle and have been important winter destinations for the Daimler Buses test team for many years. Here the main item on the agenda is the driving dynamics testing on the iced-over lakes at Arjeplog. The Electronic Stability Program (ESP), for example, has to prove itself under extreme conditions in skidpad tests on specially prepared icy surfaces.

Specialist local "icemakers" prepare bespoke driving surfaces for testing new buses and components: as soon as the lakes have frozen over, snow is regularly cleared from the ice surface to allow the ice to become extremely thick here. This clearing increases the ice's load-bearing capacity so that vehicles can drive on it. There are roughened-up lanes, ice-slicked stretches and almost impassable icy tracks coated with a fine water mist - whatever the testers ask for and the test schedule demands. Perfect for test drives under constant conditions.

The water beneath the several-metre-thick ice layer on the lakes is over 200 metres deep. But there is no danger as the disciplined test drivers always stick to the prepared areas: the ice is approved for a weight of up to 40 tonnes.

Rovaniemi: tests at Santa Claus' airport

Similar climatic conditions prevail some 500 km further to the east in the Finnish town of Rovaniemi. Located in Lapland, it is considered Santa Claus' home town. There's a Santa Claus Village here and even a Santa Claus Post Office. But this is not what regularly attracts the Daimler Buses test team to Rovaniemi every winter from January through to March: here on the 66th parallel, right on the edge of the Arctic Circle, the Daimler Buses testing department has found the ideal conditions to perform its gruelling winter programme.

At the airport complex, the test team uses its own test track with skid pan as well as brake manufacturer Wabco's proving ground: an 800-metre-long straight braking track for tests on ice, snow and tarmac. It is also possible to combine different friction coefficients, such as a heated tarmac surface offering good grip on one side of the vehicle and sheer ice on the other.

Plus there is a circular "driving dynamics" skid pan with a diameter of 280 metres, not to mention a climbing hill and a handling course. In addition, the town of Rovaniemi, which has a population of around 60,000, gives the team the opportunity to test urban regular-service buses under extreme winter conditions in real traffic situations.