My age group is mixed from 1 - 6 years of age - so the younger ones are always learning as I work with the older ones
We practice monthly fire/emergency drills with all age groups - how to exit the house and where to meet in an emergency whomever is the 'oldest' in care is in charge of being 'fire helper' the ones I work with on what to do in an emergency - aka if Reggio falls down and cannot get up you call 911 and tell all your friends to sit down on the couch, put the baby in their booster seat and so forth until help arrives... the other younger ones learn to 'listen' to this person during practice scenarios like this ... IMO the more you 'role play' emergencies and what to do in them the less 'scary' they are for children if they ever DO occur.... knowledge is power and you tend not to 'fear' the things you know how to deal with - so fire drills do not make them scared or paranoid of fire but rather in 'control' of should something like that happen. When they are all 'young' and not really old enough what I am really practicing is to make sure that in an emergency I am prepared and can get a group of wee ones out safely - cause the more you practice the more you realize things like 'what will I do if it is winter and they are all without footwear - better make sure to have a tarp and blankets in my shed to keep they dry and warm and so forth.
As for crossing the street - we work on this all the time to. At every cross we say 'look left, look right - are they any moving cars in sight? If not hold your hands nice and tight and make your feet go left and right!