Yes if your speed worry you, you should not be recording video with anything while driving, cuz< your speed can always be ascertained as a result of something ( 2 points ) you can go measure the distance in between, and the time in the video it took you to cover said distance, then it is just a matter of math to scale up to your kmh or mph speed.
If it is a matter of the look of the video, you can crop the bottom part with the speed out of the video, but this of course mean you have to do some post production.