Just curious-is this safe?

DD is 5 years 6 months, 44lbs and 42 inches.

She normally rides harnessed in her Nautilus in our main car (2005 Ford Freestar). She does not seem to fit right in the Nautilus in booster mode and to be honest, I like that she can do the straps herself. In DH's car, she rides in a highback Turbobooster.

Due to company and shuffling of seats this weekend I suddenly realized this morning that the Nautilus and the Turbobooster were in Dh's car (at work), leaving me with our spare backless Cosco booster seat that we sometimes use for dd's friends who are normally in nothing in their parent's cars. I let her ride in the backless booster for the first time because I figured it was better than nothing.

Surprisingly, the fit was great. The lapbelt was low across her lap and the shoulder belt seemed to fit her just right, too. Also, she loved it. Most of her friends ride in these and I think she finally felt "normal." We didn't go very far. Just to school, but it got me thinking. How much less safe is she in a well-fitting backless booster than she is in her Nautilus or her turbobooster? Would it be OK to occassionally let her ride like that? I just have always heard no backless boosters until at least 8, but what if the fit is great?

I am not planning on making any drastic changes, but like I said, it just got me thinking.

Two articles... one that says highbacks are best http://www.eurekalert.org/pub_releases/2005-09/chop-htb090905.php

And one that says it may not matter (to the surprise of the people doing it, based on the above, earlier study!) http://www.webmd.com/parenting/news/20091019/car-booster-seats-cut-injury-risk-for-kids

I'd be leary of using a backless before my child was at least as tall as the 5th % adult female dummy, who's head is high enough to reach the airbags in a car with curtain airbags (I think 31" is the number, butt to top of head when seated in the car) that I've read.

My van has no curtain airbags so I keep my outboard kids in boosters as long as possible, 10-12 or so, and honestly, they don't care, they know it's because it's safest and not negotiable (they ride backless in other's cars, I figure it's easier and a backless is safe enough for only a few miles here and there).

From what I understand, it's not that they will fit poorly in a backless at that age. I think it's more the extra protection and a place to lay their head when they sleep so they dont slouch into a dangerous position. Mainly, the extra protection of course.

It's safe. But it's another step down. KWIM? Kinda like a older RFer (say 3.5 yrs old) is safe FFing if properly strapped in, but would be safER RFing. The kinda thing that's your call and neither is really dangerous.

JMO. I could be way off. lol. I'm interested to see what others say.

I'm not comfortable at that age letting a child ride in a backless booster. High backs are 70% safer. Keep in mind most accidents happen close to your home. In an emergency yes it's safer than just the seat belt.

In the situation you were in, yes, you are fine. For other emergency situations like that, Yes, you're fine. For daily use, I wouldn't. My ds is 8 1/2 and only recently moved to a backless and that's only because he's too tall for the back on his TB.