Often computed at national level, road mortality can be misleading when computed at city level, as activity levels in some cities cannot be measured by resident population alone. In urban cores, where many jobs and services are concentrated, the daytime population can be much higher than the resident population. This figure is important to better capture the activity level within an area and was provided by 19 cities. In FUAs, the assumption is that resident and daytime population are not significantly different, since the FUA definition is based on commuter flows.