Tesla’s recall of more than 2 million of its electric vehicles — an effort to have drivers who use its Autopilot system pay closer attention to the road — relies on technology that research shows may not work as intended. Tesla, the leading manufacturer of EVs, reluctantly agreed to the recall last week after a two-year investigation by the U.S. National Highway Traffic Safety Administration found that Tesla’s system to monitor drivers was defective and required a fix. The system sends alerts to drivers if it fails to detect torque from hands on the steering wheel, a system that experts describe as ineffective.