If you want to get a good place on the sandy beaches level listen up. If you go through the waterfall that is one shortcut. But if you veer left and accelerate to a fast enough speed, you can launch yourself over the gaurdrail and into a lake. Sometimes you may pop up as close to the finish line as the last nitro but sometimes as far away as just around the corner.

NOTE: Make sure not to jump backwards because you may get sent back to the tunnel that is through the waterfall.