Stones and debris falling off lorries actually causes a lot of issues like this. It's one of the reasons we always recommend dash cams, even to people who argue they'll never get into an accident. To record footage of the other side of the road, or for multiple lanes of traffic, you'll want something with a wide angle lens. You haven't stated a budget, but for something with very little faff to set up, a decent lens and an affordable price (£45) - I'd recommend the YI Smart. We reviewed it here (you can also buy straight from the review page if you like the sound of it): kit.honestjohn.co.uk/reviews/review-yi-smart-dash-.../

You can either plug it in every time you get in or out of your car (which I do) or you might be able to get it hardwired, which won't drain the battery if you leave it plugged in.