I absolutely do not think that you are being overly worried. A car is a car and you should ALWAYS use a car seat. The worst thing you can do is put your child on your lap - if you are in an accident, your weight will push your child forward, compounded with speed - bad idea. Never let people bully you about your child's safety or anything else for that matter. Every time I second guess myself and do what someone else thinks rather than what I think, even those with our best interests at heart, whether it's nap skipping or whatever, I always regret it. Now, for your question, I do recall seeing a fold-up, if you can believe it, car seat, but I'm not recalling the name, I do recall it being expensive. I walk everywhere. On the bus into the city I do have her on my lap, but I don't know of any other options. She's 18 months. Hope this helps you, in some small way!!