I wish there were more requirements but could be very difficult to enforce.
On my daily commute I go down a long "corridor"(Wilmslow/Oxford Road) into city centre Manchester with unis, student halls and at least one school, a major hospital and numerous businesses including the very popular Curry Mile, part of which corridor is also apparently the busiest bus route in Europe.
There are loads of cyclists, many of whom have no helmet, totally unsuitable clothing (long flowing skirts or cardigans), no lights/high vis, headphones in etc... I've seen some very close calls and some accidents, one awful one (albeit in a different area of the city) with a cyclist lying dead in the road after an accident. Of course I'm not saying all the incidents were their fault, not at all, but I've often reached well into double figures counting cyclists without a helmet just on the stretch I take (I tend to give up after about 20).
There was an article on it in the local press not long ago:
http://menmedia.co.uk...cidents-in-manchester