I’m reading Bob Mionske’s excellent book Bicycling & the Law (available from velogear), here is what I distilled out of the section on car insurance and liability systems as it relates to Arizona.
Arizona operates on the traditional “tort liability” system. By comparison, the three other systems used in decreasing order of popularity are: no fault, hybrid, and choice.
Furthermore, Arizona uses the “pure comparative negligence” basis — that is where damages are awarded solely (“purely”) according to whatever percentage is assessed. The other two systems are modified comparative and contributory negligence.
As an aside — the contributory negligence scheme seems particularly onerous. That is where a party having any percentage (think e.g. 1%) of negligence cannot recover any of his damages. I’m sure there’s some historical reason for all of this, interestingly all the states that use contributory negligence are clustered in the mid-Atlantic region: Virginia, Maryland, D.C., North Carolina, and Alabama.
Here is an article that has more details on Comparative Negligence in Arizona by Greer & Alles, PLC… “Arizona follows the doctrine of pure comparative negligence. The comparative negligence statutes are found in A.R.S. § 12-2501 et seq. …The comparative negligence laws provides that each defendant is only liable for the amount of plaintiff’s full damages allocated to that defendant in direct proportion to the defendant’s percentage of fault and a separate judgment shall be entered against the defendant for that amount”