From what I have been told, the EPS foam actually has little effect. Kids need to be in a carseat or a
booster until around 4'9", 8 years or 80lbs. Basically until they can pass the 5 step
booster test
Boosters Are For Big Kids
With the
Radian, they JUST passed it to that 53" height, BUT this means that your child's shoulders can go over the top harness slots. As a tech, I just don't see how they were able to pass this. When a child is
FF and their shoulders are over the slots, if involved with a crash like this, it causes spinal compression. So, I really don't know how they have done it.
do you have any other children that ride with you? The
Regent is a very large seat, but I have seen it in 2 door Cavalier's, small Kia Optima's, etc. If you are wanting to get a seat that will basically fit your child until you are done with carseats/boosters, the best route would be the
Graco Nautilus. (there are rumors that
Britax is releasing a seat POSSIBLY in April called the Frontier. It is supposed to harness to 65lbs, then
booster to 100+lbs)