Nissans will remind you to check the back seat before walking away

The idea came from the smell of sun-baked lasagna.

Smart cars don't just mean built-in Google Maps or radar-assisted cruise control. Nissan, for instance, is making a different kind of safety feature standard equipment: a sensor that reminds you to check the back seat for any errant loved ones. The feature was inspired by a pair of engineers, and the resulting days-long stench of garlic and cheese after one left a plate of lasagna in the car overnight. Those engineers, Elsa Foley and Marlene Mendoza, hold the patent for Rear Door Assist.

Rear Door Alert works by monitoring if the rear doors were opened at the start of a trip, but not opened when you park. RDA will start with an instrument cluster notification to check the back seat, and from there it "progresses to subtle, distinctive chirps of the horn" if you still haven't opened the rear door.

Nissan promises the feature will be in all its vehicles by 2022, and in the 2019 model year it's baked into the Altima and Sentra sedans, and the Rogue. You might've even spotted it in 2018 Pathfinder SUVs, too. This isn't the first time we've seen the feature -- GM offers something similar -- and Nissan promises soon enough we'll hear word of another five models rocking it as standard equipment.

Of course, you could always double-check the cargo area and back seat yourself before leaving, but it's nice to have a reminder in case your infant or dog is taking a nap.