Long sleeves for safety?
Unless you're out derbying or have a complicating balance issue I wouldn't worry about it.  Falling off a bicycle when commuting or recreational riding should become an extremely rare experience with practice.  Tank tops and shorts are perfectly acceptable bike wear in the summer.

Ice is of course a different beast; the best advice I have for ice is that you should be prepared to fall and do not have anything in your pockets that you don't want embedded in your leg.