"I was rear-ended the other day. It was hard enough to give me whiplash but was still slow-speed enough to be considered low impact. I was alone in the car (thank the gods!) but my year-old son's carseat was in its usual position in the backseat.
The carseat's literature was very clear on the subject of car seats and accidents when baby is in the car seat: replace it immediately. But it is completely silent on the subject of empty car seats and accidents.
The seat was properly fastened in the middle of the rear bench seat with the lap belt, and was tethered in place with the tether strap as per Canadian law. The provincial government's website is silent on the subject of unoccupied car seats in the event of an accident. Our insurance provider couldn't give me a definitive answer, and neither could the local police department. (The rent-a-cop at the police station's front desk actually made fun of me for asking the question!)
So what do I do? The insurance provider thought that given it was low-impact and the seat was not damaged that it should be OK. But I can't help thinking this is sort of like if your hard hat gets hit in a workplace accident: even if there's no visible damage, you replace it because it's a safety device that's been in an accident."
My only advice is to go back and kick the rent-a-cop in the shins for making fun of you for being concerned about your son's safety. Jerk.
But I went right to The Car Seat Lady, Alisa Baer, to answer your actual question. Here's what she said:
The National Highway Traffic Safety Administration (for the U.S.) recently changed its recommendations regarding replacing a car seat after it has been in a crash. The data behind these recommendations came in large part from a Canadian study. Please visit NHTSA's website for more information. Given the fact that you were injured in the crash you should replace your son's car seat (according to the NHTSA criteria) -- regardless of the fact that it was unoccupied at the time of the crash. Even unoccupied seats are stressed in a crash -- obviously less than an occupied seat, though.
One other thing I would recommend -- if your son's car seat can go rear-facing (and your son is within the weight and height parameters for rear-facing) it would be wise to keep him rear-facing until he reaches the weight or height limit for his seat. Rear-facing is about 4 times safer than forward-facing - see www.thecarseatlady.com for more info on rear-facing vs. forward-facing.
Alisa Baer, MD
Nationally Certified Child Passenger Safety Expert
So there it is, right from the actual expert's fingers. I hope your insurance company will be easily persuaded to replace your son's seat by the information in the link Alisa gave to the new NHTSA position. I hope your neck is feeling better.