I figured it out. It's pretty annoying.
1. Use the first spring to jump to the second.
2. Double jump on the second spring to reach the top platform.
3. Make sure to land on the far left part of the platform, and as soon as you land, tap your boost until you reach the right edge of the platform.
4. When you reach the edge of the platform, do a double jump and boost the rest of the way to the top of the police car.
Hope this helps.