Trailer Bike (Kid's Tandem)

A few years ago we bought a trailer bike, or a kid's tandem, from a local bike shop.  Our kids could bike, but it was very slow going at their pace.  So we thought if we could attach them to us it would be better.  The investment of that trailer bike was a very good one.  We have taken long bike trips with the kids.  How does a trailer bike work, you ask?  The trailer bike attaches to an adult bike, and the child can pedal all (s)he wants.  The child can not brake.  When the child pedals, it helps the adult in front in the effort of moving, especially up hills.  Does it help the child learn balance?  I don't think it does.  But you and your child get a workout and enjoy the outside world.  The child does not have to pedal, so if the child has her/his feet on the pedals not moving, the adult can still pedal away.
The one issue to be aware of is that when coming to a stop the child needs to stop pedaling.  A child pedaling excessively can make both of them go into a dangerous intersection.

http://en.wikipedia.org/wiki/Trailer_bike