Food, California has comparative fault, where fault can be apportioned between all the parties, example-one party was speeding, but the other ran the light.

Joint and several liability means fault can be apportioned, but if one defendant can't pay, the others become liable for the entire amount. That is why you see cities or other state agencies named in accident suits (bad road, poor signage, etc.) because they have the money if the other motorist doesn't.

Is this fair? Not really, but the public policy is that the innocent party shouldn't suffer because one of the liable defendants can't pay the damages.