I wish I could put college students in a trailer and carry them around. Then I could drop my 2nd car and be in really great shape. =) I would be really doing well on mileage reimbursement too. LOL Keep it up at least as long as the kids are willing. Your kids are getting fresh air and are being modeled to not be sedentary humans. Being obese is the worst health risk in the country and I think you might be keeping your kids from falling into that category with you current habits which lowers their health risk. So is really riding in a car safer? Maybe maybe not. There are so additional variables that haven't been considered by your co-workers. Maybe you are worse driver than you are a bike rider. j/k although I know some people like that.