WASHINGTON, Oct 19 (Reuters) - President Joe Biden plans to nominate the No. 2 auto safety official and a former California Air Resources Board official to head the National Highway Traffic Safety Administration (NHTSA), the White House confirmed on Tuesday. Steven Cliff, who has been deputy administrator since February, has been a key figure in the Biden administration"s proposed rewrite of fuel economy standards through 2026 and is overseeing the department"s ongoing safety probe of Tesla Inc (TSLA.O) and investigation of whether 30 million vehicles produced by nearlytwo dozen automakers have unsafe air bags. Reuters first reported Cliff"s planned nomination earlier on Tuesday. An official separately told Reuters that Duke University engineering and computer science professor Missy Cummings is being named a new senior adviser for safety at NHTSA. NHTSA, which is part of the U.S. Transportation Department, faces a backlog of pending auto safety regulations and has not had a Senate-confirmed administrator since January 2017. There has not even been a nominee for NHTSA"s top job since 2019. NHTSA in August proposed dramatically revising the Trump administration"s rollback of Corporate Average Fuel Economy rules, proposing increasing fuel efficiency by 8% annually for the 2024-2026 model years. Cliff, a former deputy executive officer at the California air board, said the proposal reduces "climate pollution by approximately the same amount as if we took more than 5 million of today’s vehicles off the road." Since the COVID-19 pandemic, the United States has seen a sustained increase in traffic deaths that NHTSA has ascribed to impaired driving, speeding, a failure to wear seatbelts and other unsafe behavior. NHTSA last month estimated 8,730 people died in vehicle crashes in the first three months of 2021, compared with 7,900 deaths during the same period last year - up 10.5% despite a 2.1% drop in miles driven. Last month, NHTSA asked Tesla why it has not issued a recall to address software updates made to its Autopilot driver-assistance system. NHTSA in August opened a formal safety probe into Tesla"s Autopilot system in 765,000 U.S. vehicles after a series of crashes involving Tesla models and emergency vehicles. NHTSA in June issued an order requiring automakers and operators of vehicles equipped with advanced driver assistance or automated driving systems to immediately report crashes. Cummings in a 2018 interview said the United States needs "an entirely new regulatory framework where an agency like NHTSA would oversee" autonomous vehicles, adding the agency "does have the authority to mandate testing and other interventions, but they’re not doing it."