Why am I at fault if I swerved to miss a car that ran me off the road?

I was on a roadtrip with a friend when we saw a car driving all over the road. We tried passing him but he started moving into our lane so I jerked the wheel to avoid being hit. We managed to avoid an accident, but I hit a big rock on the side of the road that damaged my car. I called my insurance company to file a claim and they told me that I would be considered at fault since there was no other vehicle involved in the accident. How can I be at fault when I avoided an accident with another driver that was being reckless?

In most single-vehicle accidents, the driver involved is normally considered at-fault because there simply isn't another person on which to place blame. The situation might have very well gone in your favor if the other driver had made contact with your vehicle, but it would be next to impossible to prove the other driver was the reason for the accident when no other vehicle is damaged. Avoiding an accident is a tricky thing, but driving your vehicle off of a roadway can be significantly more dangerous and will normally lead to a finding of fault by your insurance company if you file a claim. Essentially the insurance company is saying that you made the choice to move your vehicle off of the roadway rather than being physically pushed by another vehicle. It is nit-picky and I'm not exactly a fan of being blamed for avoiding an accident either, but that's usually how it works in this type of incident.