For most cars and carseats, the middle position is safest. But if for some reason you cannot put it there, the drivers side is safest. Statistically, side impact crashes happen more on the passengers side due to the drivers natural instinct to protect himself/herself.
Just thought I'd throw that out there in case you didn't think of it. I have the type of luck that, heaven forbid, I were to get into an accident, it would happen on the side the carseat was on, but the statistic gives you a reason to put it on that side instead of just randomly choosing.
Re: PSA: Carseats
This. I'm trying to decide where to put DD and new baby. I'm leaning towards new baby on drivers side and DD on passenger.
The backseat is very safe. Rear facing is even safer. The safest place for your carseat is where you can get a good solid install and correctly buckle your child in.
Vanessa
Child Passenger Safety Technician.
See "most cars".