This time of year we hear about the dangers of heatstroke in locked cars. Well, there’s technology to prevent that. Nissan says Rear Door Alert will become standard on all their four-door models. If you drive a 2018 Nissan Pathfinder you already have the safety device. Here’s how it works: door sensors detect if the rear door is opened prior to the vehicle being set in motion. If that's the case, along with a message display on the center instrument panel, Rear Door Alert honks the horn to remind drivers to check the back seat after the vehicle is parked and the rear door is not opened. Nissan plans to add the safety feature to eight more models for 2019, including the Rogue and all-new Altima. By model year 2022, Rear Door Alert will be standard on all Nissan four-door trucks, SUVs and sedans.