We got a hand-me-down iBert bike seat (thaaaaaank you A+S+J).
Most people biking with a kid have the seat that attached to the back of the bike. There’s also the trailer that sits on it’s own wheels, down on the ground behind the bike. Our front-attached bike seat is much rarer. It’s a newer design, and there are grumblings that it’s not as safe — though I disagree.
I’m not an expert. I’m not sure who would be the most qualified to speak to the safety of each bike seat, but I can give you my opinions. I’ve been in bike crashes before, and if my bike slides out from under me I’m going to have my hands on my handlebars and be able to have a small amount of control of the front of the bike, and help guide it down. If it’s a head-over-handlebars, I don’t know if either seat is going to be better or worse. That’s where wearing a helmet, long pants, and shoes is important.
In summary, the iBert is the best commuting or street-biking seat style.
The other option I’d consider is the bike trailer:
The safety issue for me is having a trailer down where cars can’t see it. An upside to this kind of trailer is that there’s lots of room (you can put two kids in there), there’s protection against the elements, and if you were to lose your balance they’d be low to the ground already.
The trailer is a great option if you’re on bike trails, or otherwise not in traffic.
The most popular bike seat I’ve seen is the rear-attached seat:
I’m not a fan of this seat. It puts the kid level with your ass, so their main view is blocked. It’s also hard to hear them, and you can’t see them without turning around and looking down (which is hard to do and dangerous while biking). They do have a higher back, providing more support for wobbly heads. The downside is some models don’t account for the child wearing a helmet, which means the child’s head is pushed forward and they can’t rest comfortably.
You can get the iBert on Amazon for something like $90, which is the same price as the mid-range rear-attached seat, so I can heartily suggest the iBert.
Here’s a video of Jason and 80 in the seat: