You must complete 30 laps of the Sprit-Raceway R track;
(This track must be unlocked by completing races in Career mode)
At the Main Menu select Single Race.
Then the easiest way to win this race and unlock the achievement is by selecting the following pre-race options:
Nitro Booster: On
Vehicle Damage: Off
Number of Laps: 30 (as required by achievement)
Number of Opponents: 1
Opponents' Vehicles: Mixed
Oppenents' Strength: Easy
Track Type: Circuits > Autobahn > Sprit-Raceway R
Now complete the race and after all 30 laps, your achievement will unlock.
(You don't even have to win the race, just complete 30 laps).