Now I'm confused. If CA is a no fault state (which it isn't) then there shouldn't be a criminal case, since if there is no law against it, you can't be charged with it. That's logical.
However, every time someone is injured or killed in an off road incident, the CHP comes out and investigates the details, takes BAC measurements, which indicates to me that someone can be held accountable in an off road collision and the facts of the collision, including the BAC of the parties involved may very well come into it.
This was copied off of a law firm website, link below. They don't mention no fault, but do discuss assignment of liability.
Off roading accidents frequently result in severe injuries and even death. Many off road vehicles, such as ATVs, ROVs, and dirt bikes, provide very little protection for drivers or passengers. When an injury occurs as a result of an off roading accident, liability may be difficult to assess and
the injuries can be rather severe.
In an off roading accident involving no other vehicles, frequently the driver of the vehicle will be considered to be at fault. If there were passengers who were injured, they would potentially have a claim for damages against the driver. If the vehicle malfunctioned or crashed as a result of a defect, the manufacturer could potentially be held liable. Additionally, if the land or vehicle were in a condition that made them dangerous to off road on or in, then the respective owners may be held
liable for negligence.
Passenger Injury and Assumption of Risk
In some situations, a passenger may be presumed
to have assumed the risk of injury when they decided to ride as a passenger in an off road vehicle. For example, if a passenger knew that the driver of the off road vehicle was drunk or even inexperienced, it can be argued that the passenger assumed the risk of injury by agreeing to participate in a highly dangerous activity.
Simply going off roading likely does not mean a person is assuming the risk of injury. However, if circumstances, such as riding with a drunk driver, make the activity clearly more dangerous, then the legal theory of assumption of risk may apply. The legal theory may totally or partially defeat an injury claim depending on the circumstances.
Insurance Coverage
Even though an accident happened off road, frequently if the vehicle does have a valid auto insurance policy, then there may be insurance coverage for any injuries sustained. Unfortunately many off-road vehicle owners do not purchase liability insurance for vehicles like ATVs or dirt bikes if there is no plan to drive them on regular roads. The CPSC actually recommends
not using off road vehicles on roads due to multiple safety concerns.
If there is no auto insurance, a homeowner's policy may be able to provide coverage for injuries. Additionally, where a minor is liable for the accident, a parent's home owner's policy may be able to cover the injuries.
https://www.findlaw.com/legalblogs/personal-injury/off-roading-accident-liability/