All the time, especially in low incidence high impact scenarios. You must wear a seat belt ("don't get killed in a crash"), your brake disks must be at least th

All the time, especially in low incidence high impact scenarios. You must wear a seat belt ("don't get killed in a crash"), your brake disks must be at least this thick ("you should be able to stop before your brakes fade"), you cannot use a mobile phone while driving ("you must pay attention to what's going on around you"). Concrete requirements are much easier to police, even though they may not reach the intended end goal completely (e.g. distracted driving due to hands free calling).