Because there is only really one type of bicycle. There are many types of road vehicles. Saying "a driver" doesn't differentiate smart car from City Bus - sometimes the size matters (heh) when visualizing the situation.
I suppose those are those recumbent bikes...
The Record has an article now about this: http://www.therecord.com/news-story/6958...cambridge/
I suppose those are those recumbent bikes...
The Record has an article now about this: http://www.therecord.com/news-story/6958...cambridge/