Select "Time Trial"
There are 16 tracks, four in each zone. Pick any track.
If PERSONAL BEST is listed on the track ghost times, you have completed it already, so back out and take the next track. Otherwise, pick the Staff ghost or a global time to compete against (you do NOT need to beat that time)
Enter the race with any car you wish. You will get a rolling start and a full boost meter with four boosts. Simply drive one single lap around the track. When you cross the finish line, you will get a Personal Best sign. Immediately exit that track, and then move to the next track.
Once you have done this on all 16 tracks, the achievement will pop. If you can't remember if you have a done a track, no problem. If you don't have a personal best listed after you select a track, you still need to do it.
This can be paired nicely with the Wheeler Dealer achievement, complete a race with every car in the game. Just switch to a new car each race. Doing one lap on a time trial counts as completing a race for that achievement.