U.S. wants 4-year phase-in for higher NAFTA auto content thresholds U.S. wants 4-year phase-in for higher NAFTA auto content thresholds April 30, 2018 dzadmin Comments 0 Comment The latest proposal for updating NAFTA’s automotive rules from the United States would carry a four-year phase-in to meet a higher, 75 percent regional value threshold as well as new labor rules.