I have two kids, aged 2 and 4, which I drive to kindergarten every morning.
I currently have a rear seat and a trailer, but the roads and sidewalks are a little too narrow for the trailer.
I want to move my older daughter to a trail-a-bike, and have my younger son on a child seat.
I heard many warnings about using front mounted seats, but most trail-a-bikes don't allow a rear seat as well. (I only found one that does allow, but it costs 350 EUR http://www.roland-werk.de/engl/addbike ).
I thought of buying a trail-a-bike which attaches to the seat post, and weld a rear chair to it. Has anybody done such a thing or thinks it is unsafe for some reason?