3odys4me:
<font face="Verdana, Arial" size="2">I have seen this one before. When you say "permanently installed," how so?</font>
In that it's mounted like a baby seat: you strap it in with the car's seat belt and it stays there and the car's seat belt never comes undone; instead, you use the seat's 5 point harness for the child.
<font face="Verdana, Arial" size="2">My concern frankly is relying on two systems to work effectively in the event of an accident; the vehicle seat belt and the car/booster seat's belt as opposed to just one. I know firsthand that the seat belt alone worked great in the accident we had. No matter how tight you get it, seats secured with the seat belt seem prone to move</font>
Oh my--then you need to go to the local police or fire station and have someone install the seat for you and show you how it's done.
My car seats have never moved. It takes some effort, but the goal is that the child seat becomes one with the car's original seat. The child seat should never move relative to the car's seat. If it does, it's not really installed correctly.
For example, I have a Britax Roundabout. I tighten the harness by pulling a strap at the lower front of the seat. I don't need to hold onto the Britax seat to hold it still as I pull the strap; I just pull the strap. The Britax seat doesn't pull forward as I do this, because it's held to the Ody's seat like it was welded there.
If you're the type to remove and reinstall the child seat regularly for whatever reason, it's more likely that you're not installing it well enough. For example, I bet most people who try to use one car seat for both parents, or to give to the grandparents as they babysit, don't use the tether in something like the Ody. It's just *that* much more difficult, and they rationalize its use away.
I realize that's the human tendency; that's why I buy car seats for everyone, car seats that we leave in the car. I have one in my little Civic, just for emergency purposes. It stays there, properly installed, even though it gets used maybe once every month or two. Sure, it's $100 sitting in the back of my car doing nothing most of the time. So what? It's rigidly installed, super tight, with tether attached. So when we need to put the boy in there for whatever reason, we don't hesitate or hem and haw or reason that "we're only going 6 blocks, he'll be OK without a car seat, we'll just drive slowly". He's buckled into HIS seat just like Daddy is buckled into Daddy's seat, no questions asked.
We also put one in Grandpa's car, where it sits the same way. I consider these to be "permanently mounted" in that they don't go in and out all the time; they just stay there, ready for use just like the regular passenger seats in a car.
Hey, think about it: why did I buy an Ody in the first place? Partly because of the Magic Seat! Because I don't think part of the car owning experience involves removing and installing passenger seats. The same goes for child seats, IMHO.
Go talk to your local fire department. They'll tell you all about this. You *can* properly install a child seat so that it becomes one with the car, and there's no concern over using two systems.
Also ask them about a 5 point harness. I think they'll agree that if it's available, it's preferable. Quite frankly, it's much easier--particularly on a regular and ongoing basis--to get the 5 point harness onto the child properly each time than to maneuver the car's seat belt onto a belt-positioning booster properly. (And that's the same as with the LATCH philosophy: LATCH is easier. LATCH isn't necessarily better than car belts, but you're more likely to use LATCH properly than you are car belts.) But again, that depends on how well you've installed the child/youth seat using the car's belts and the manufacturer's tether.
<font face="Verdana, Arial" size="2">I don't know for sure. I'm just into minimizing risks.</font>
Sure. We understand. And the 5 point harness seat, appropriate for the child's weight and size, installed properly according to the manfuacturer's directions and taking into account the laws of physics (i.e., strap that baby TIGHTLY to the car's seat so that the child seat doesn't move a millimeter in any direction), is the best bet for minimizing risks.
We're also going to put our soon-to-be infant into the very center seating position, I think, again to mimimize risk. She'll be the weakest one, and she'll need all the advantages she can get if an accident occurs.