More and more children are going without booster seats in cars—to potentially devastating effects. “The single largest killer of American children is car crashes,” says Jon Sumroy. “This is a public-health emergency.” One contributing factor could be that kids’ booster seats are too bulky to easily carry when using ride-sharing services like Uber and Lyft. Sumroy’s company, Mifold, hopes to help reverse the trend with the Hifold ($160), a 10-lb. high-backed booster seat that has already been adopted by tens of thousands of families. Designed for kids from 33 to 100 lb., the Transformer-like device has adjustable head, torso and seat panels and collapses to roughly the size of a backpack for easy toting. “The world today is going through a personal transportation revolution,” says Sumroy. It’s time that booster seats caught up. —J.R. Sullivan