Federal regulators are investigating nearly 3 million Teslas following reports of crashes linked to the automaker’s self-driving technology. The US National Highway Transportation Safety Administration (NHTSA) said Thursday it was focusing on incidents in which Teslas failed to stop at red lights or drove on the wrong side of the road — sometimes slamming into other vehicles and causing injuries. It’s the latest effort from regulators to scrutinize Elon Musk’s electric car maker, which has