Here’s a post covering a number of good points about why outlawing children under 6 on bikes or trailers is sheer inanity.
http://totcycle.com/blog/family-cycling-outlaws.html
Yes: obesity epidemic, heighten fear of cars, avoid traffic reduction, avoid slower speed limits, lets use sketchy data from a single survey to pass another law! Lets make it illegal to bike our kids to school and to parks and their play dates. All hail nannytopia!
Wow, both my kids where riding their bikes with out training wheels by 6.