Do "trailer bikes" help kids learn to ride a bike on their own?
He is 3..... he will do what he wants to, when and how he wants. I had a lot of trouble getting my boy off trainers (We did not go don the balance bike path). After many attempts involving removing them and putting them back on, I gave up and decided when he is ready (or old enough his peers laugh at him), he will want them removed. One day he just came up to me and asked me to take them off.

Choose you battles carefully - only pick ones you will win, and only fight those that must be won. This is not one of those battles.  

So should you get a trail along bike? If its to get him riding quicker/better/faster absolutely not. if its because its a fun way to spend time together going at pace you can both enjoy then its a great idea. 

There are towbar attachments that clip to  a standard bike, lift the front wheel and give a similar effect to the tow along - but if you boy wants to go solo for a bit, unclip and away he goes.  When/if he get to tired to do more riding, clip him back in and you do the work. refer What should I look for in a &quot;trailer bike&quot;/&quot;tag-along&quot; bike for a child?