We live in a city too, don't have a car, and we have a car seat. Well, it's in storage now and DD now uses a booster. There are times when we need it: we couldn't leave the hospital (DD was born in a hospital) without one. My parents bought it at Costco, I believe, but it was safe and is still in good condition. Are you in NYC? If so, PM me and we'll give it to you.
Although we don't have a car, we rent cars from time to time to travel to the mountains or out of state, and it has gotten good use. FYI, as it now stands in NYC, cabs and cars for hire don't require car seats...they only require that the child be restrained (either in seatbelt on parent's lap, seatbelt if under 12, or sling/carrier on parent's lap. I rode in a police car with DD in a Bjorn on my lap (our apartment was broken into and the police took me down to the police station to report).
I just think it is good policy to have a car seat for whatever crops up. Again, I have a car seat that I'd like to give away. If you're in my town, PM me!
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