Regulation 613 of The Highway Traffic Act stipulates that children in booster seats (under eight years old, weighing less than 36 kilograms and under 4-foot-9) can only sit in the front if the air bag is deactivated. In Ontario, turning off the air bags when kids are sitting in the front seat isn't just a recommendation - it's the law, says Ontario's Ministry of Transportation. "A sophisticated seat occupancy detector measures the weight of a passenger and can regulate the deployment of the passenger airbag." "It is definitely possible for a child to be a passenger in the smart fortwo," says Mercedes-Benz Canada spokesman Michael Minielly. Some cars, like the Smart car, turn off the air bags (or adjust their speed) for you, based on the weight of the passenger in the front seat. "Even in a small crash at low speeds, if the child is under 4 foot 9, they can get neck lesions and face lesions from the air bags." "If it's possible, deactivate the air bag - or if you can't, push the seat back as far as you can," Cyr says. The front seat has extra perils: front air bags deploy at 300 km/h or faster, and the front seat is closer to the impact in a front-end collision. If you're in a two-seater car or a truck without a back seat, it's fine to put a child in front, as long as they're in the correct seat for their height and weight - that varies by province. The CPS and the Canada Safety Council say the back seat is the safest place for children, period. "The law says you have to use an age-appropriate safety seat and it has to be buckled up." Claude Cyr, a pediatrician on the Canadian Paediatric Society's (CPS) Injury Prevention Committee. "It's not prohibited for kids to be seated in the front," says Dr. The front is fine as long as the kids are properly restrained and the front air bags are turned off, safety experts say. There are no specific laws banning kids from the front seat in any vehicle. What is the law regarding children under 10 riding in the passenger seat of a two-seater car such as a Smart Fortwo?