Mostly unavoidable. It could have been gusting more than you realize, plus the gimbal pitch angle and drone flying speed matters too. Slower gives cleaner results. Most often it comes down to editing out things of that nature. I understand this is an example video to show the problem, but a lengthy video of following the car is not interesting and would (should) typically be edited down to short edits mixed in with different angles. Unless it's for a specific reason, people need to be brutally honest about how interesting a video is in whole, which usually means trimming out a good 50% and more. Anyway, good luck and have fun.