The authors also note that driver behaviour is a hugely important and unquantified factor, they urge more qualitative research in this area and note «in order to reduce perceived risk and encourage more cycling... reducing or calming existing motorised traffic must be explored first... lane
width is the most significant variable to achieve a sufficient
vehicle passing distance... the provision
of narrow (< 2 m) cycle lanes... may be insufficient... Reconsideration
of the
entire road design and further exploration
of driver behavioural factors is required.»