You accidentally tap a barrier while you're at full throttle. Barrier penalty: 4 seconds. Your car becomes unstable from the penalty and wipes out into the grass in the center. Shortcut penalty: 4 seconds. You're still trying to get out. Shortcut penalty: 4 seconds.
You're recovering from overshooting, a car sideswipes your front end. Ramming penalty: 4 seconds.
You overshoot into the inner area of the next turn. Shortcut penalty: 4 seconds.
You're taking a tight turn, a car hits you from behind. Ramming penalty: 4 seconds.
You're taking a turn and clip the car in front of you. No penalty. The clipping sends you inward. Shortcut penalty: 4 seconds.
You try to pass on the inside and your left wheels are in the grass. Shortcut penalty: 4 seconds. Which causes you to lose control and overshoot. Shortcut penalty: 4 seconds.
A heavier car forces your right wheels of the track. You spin out. Ramming penalty: 4 seconds.

OMG WTF? DIEPLZKTHXBYE