3 Min Read WASHINGTON (Reuters) - The National Transportation Safety Board (NTSB) urged automakers on Wednesday to improve electric vehicle emergency response guides that lack clear information and hamper efforts to extinguish lithium-ion battery fires. FILE PHOTO: A worker exits a Tesla Model 3 electric vehicle at Tesla's primary vehicle factory after CEO Elon Musk announced he was defying local officials' coronavirus disease (COVID-19) restrictions by reopening the plant in Fremont, California, U.S. May 11, 2020. REUTERS/Stephen Lam The recommendations follow a series of NTSB investigations into four Tesla electric vehicle battery fires on U.S. roads in 2017 and 2018, including three high-speed crashes in which the lithium-ion battery reignited after firefighters extinguished fires.