From BoardGameGeek.com...
After drawing your rally-track (by connecting sides of 1,2,3 or 4 boards that are each double-sided, one side with asphalt, and the other side with snow) you begin the race.

The movement system is simple : each die rolled, you advance one space. So you have 5 dice for each of the speeds and 2 of 'gas' to continue moving without changing your speed. Each die is playable once and only once each turn. When you stop your movement, you take a card corresponding to the last speed that you started: the higher your speed, the lower your time.

The track has obviously straight lines and turning areas require a certain speed that you can pass with different manners (by skidding, sharp turning, ...).

You must roll the die because it determines the speed selected, but may show a "!" which will put you in danger. The 3rd "!" displayed, your car will risk going spinning off the road, resulting in loss of time (1'00instead of the scheduled time on your card) but sometimes also damage to the vehicle as the landscape in which you go (grassland, mountain forest : loss of 0 to 2 of speed used in each round.

At the end of each round, each player adds his times for his total time. The winner is the player who accumulates the least time in total.

The ability to take risks to scrape a few seconds (and then release them to ensure a tricky) or the tire management (is it better to take slicks on the short portion snow tires or snow on the portion asphalt in a special joint ?) adds more to the simulation.