Ridekick International, a Colorado-based group whose mission is to encourage people to replace short car trips with bicycle rides has come up with a handy solution for parents who might be hesitant to pedal off on errands with the kids in tow. The Ridekick Electric Child Trailer is a motorized carrier that slots onto the back of your bicycle, and with a DC hub motor and a lithium-ion battery can push a bike on a single charge for up to 15 miles.