Not having a go at cyclists here just pointing out what all too often happens, coming down from Owler Bar one Sunday morning (just been to Chatsworth farmshop), had driven past the the Former Fleur De Lys and the Cross Scythes pubs and was sticking to the speed limit (which I do try to do anyway, although in modern cars is actually becoming harder to do), I knew that the police had their ANPR/Speed trap van parked on the island at the bottom of Bushy Wood and Abbeydale Road South.
As I approached the final dip just before the junc's of Abbey Rd Sth/Totley Brook Rd/Bushy Wood a group of cyclists (about 10ish I think) both undertook and overtook me just on the corner in that dip where the road narrows to a single lane, of course the cops are not suddenly going to and can't jump out of the van as the cyclists would have been at Beauchief traff lights by then.
I have had this happen a few times and not just there, I know this does not represent the majority of the bicycle community but am afraid it is becoming more common, just as more and more car drivers dont know (ignore) what road markings and mandatory blue background roadsigns mean (again only a minority, but I will also apply that to a minority of Cyclists as well).