The right dash cam app serves to record and backup video footage of the road in front of your car. You'll need to use your smartphone for it, making it difficult or impossible to use other apps at the same time, and it'll eventually drain the battery. As a result of these restrictions, a dash cam app is unlikely to be a great longterm solution, although it can work fine for one or two roadtrips. If you want a dash cam to use on a daily basis, we'd recommend investing in a hardware unit.