Automakers should make shielding the electronic and computer systems of vehicles from hackers a priority, developing layers of protection that can secure a vehicle throughout its life, U.S. regulators said on Monday.  The cyber security guidelines issued by the U.S. National Highway Traffic Safety Administration are recommendations, not enforceable rules. However, they mark a step toward establishing a road map for industry behavior as lawmakers and consumers pressure automakers to show how they will protect increasingly connected and automated vehicles from cyber attacks. U.S. calls on automakers to make cyber security a priority