There are three different car classes and boost systems in Burnout Paradise:
- Speed
- Stunt
- Aggression
The way you earn boost in these classes is quite different.
In a stunt car the most efficient way to earn boost is by doing stunts. This includes jumps, flat spins, barrel rolls, smashing billboards and so on. You also earn some boost by drifting, doing near misses and driving in oncoming.
In aggression class cars you earn most boost by doing takedowns, grinding, smashing and so on.