it is an essential part of an overall road safety strategy but other considerations such as emissions management to improve air quality and curbing high speeds in order to maintain smooth traffic flows and thereby reduce incidents may also be incorporated speed management is a vital element in an overall safety strategy and countries and territories that have been successful in their strategic approach to road safety have also invariably incorporated speed management as a major element in strategy here sweden s vision zero philosophy that no traffic participant should suffer a fatality or serious injury can provide guidance speed limits should be set so that crashes if they occur will not result in a death or serious injury so human tolerance for injury and the potential for protecting humans in different circumstances can be used to establish speed limits on different kinds of roads