This project assessed current or proposed protocols for improving the usability of LATCH (Lower Anchors and Tethers for Children). LATCH hardware in the left second-row position of 98 2011 or 2010 model-year vehicles was evaluated using ISO and SAE LATCH usability rating guidelines. Child restraint/vehicle interaction was assessed using ISO and NHTSA proposed procedures.ISO ratings of vehicle LATCH usability ranged from 41% to 78%, while vehicles assessed using the SAE draft recommended practice met between 2 and all 10 of the recommendations that apply to all vehicles. There was a weak relationship between vehicle ISO usability ratings and the number of SAE recommended practices met by a vehicle. Twenty vehicles with a range of vehicle features were assessed using the ISO vehicle-child restraint form and 7 child restraints; ISO vehicle-child restraint interaction scores ranged from 14% to 86%. Twelve vehicles and 7 child restraints were evaluated using the proposed NHTSA fit criteria in the left second-row position. Most styles of child restraints met the criteria in most vehicles, with the exception that rear-facing convertible restraints did not meet the proposed criteria in most vehicles.Testing with volunteers using 12 vehicles and three child restraints indicated that the overall ISO vehicle rating, ISO vehicle-child restraint interaction rating, or the number of SAE recommended practices that were met were not associated with the rate of correct child restraint installations performed by volunteers. Vehicle-child restraint pairings meeting the proposed NHTSA fit criteria had error-free installations four times as often as those that did not, but still few were error-free (16% vs. 4%).