The most effective safety device is the person behind the wheel. I wouldn't buy my daughter an IQ, only because I won't ever buy her a car! Cars are a luxury that people earn money to buy, not something that is given to them. What I WILL pay for is good driver training, including emergency handling and some track time to explore what a car will really react when you push it to the limit. What I will invest in is lots of supervised time behind the wheel to learn about looking ahead and anticipating problems and traffic flow. What I will instill is the pride in being a good driver.
We have had a bunch of fatalities in Alberta recently, and many of them involved full-sized trucks and SUVs. Why? Poor driving. Seven people were killed when someone passed in a double-solid line zone ascending a hill. We are lucky that governments decided to mandate safety as priority in terms of vehicle equipment, but they missed the most important thing: the operator. If you're concerned about your children and their safety, teach them to drive well.