Looking at the cheapest webcams I have owned and useful info.
You really want 60fps with a dashcam but that is expensive. Many cameras will say they have 60 fps but in reality they record at 30fps and then copy the frame and double them all up. Ignore the IR vision on them all, it does not work with cars very well. That said I have IP Webcams for the house that actually do work very well. I would stay away from the one time sticky pads on some of the cameras, get the suction cup ones as they can be readjusted. On a hot day it can make that sticky pad fall off. When you set any of these cameras up they may give you the option to choosing the length of time for the recordings. Always choose the shortest! If you do say 10min, you get hit, power goes out and the battery only lasts a few min then it corrupts that save. I have mine set to 1min or 3min.
First off, this is one I bought around 5 years ago, it is a terrible camera quality wise. After a few months the flip screen came loose and would not stay up, it required having to tape it up. You cannot see the light if it is a bright day so you can’t check if it is definitely recording without opening the flip. You can find a listing here though.
This one I used for many years and it is grainy as fuck but it is enough detail that if someone comes out a turning, brake checks or whatever you can at least prove them the fuck wrong! Aliexpress link. I was cleaning up my vid folder the other day and actually found old footage from this one. Bare in mind it is 6am and misty lol
My suggestion since tech has improved so much
I would look for a wifi enabled version of the newer dashcams. Some days you just see something so stupid, you want to get that clip. The only issue is you have to remember to bring it in, connect to the PC, find that exact clip and so on. It’s too much effort sometimes. With a wifi dashcam you can just take the clip straight away. I have IP cameras which are basically the same and they have this ability, it works quite well. You may need to wait a few min for it to save that segment but then you can just download to your phone straight away, without interfering with the recording.