Interesting how people try to defend speeding when news stories such as this one (Rise in deaths on Bristol's roads) appear - just look at some of the online comments. Of course we should want everyone - all child and adult pedestrians, all cyclists - to use good road sense but no-one should defend speeding or other irrresponsible forms of driving, not least because it contributes to one in every four deaths as a result road collisions (see RoSPA link below). Speeding is unacceptable, period - it is an avoidable cause of death and serious injury if people show some responsibility.
Inappropriate speed contributes to around 13% of all injury collisions, 16% of crashes resulting in a serious injury and 24% of collisions which result in a death. This includes both 'excessive speed', when the speed limit is exceeded but also driving or riding within the speed limit when this is too fast for the conditions at the time (for example, in poor weather, poor visibility or high pedestrian activity).