Excellent question which makes it clear what the focus will be. You can make a good opening by sharing some statistics about accidents and how texting is similar to driving while under the influence. You can discuss solutions that are laws and also talk about how each person needs to choose to follow those solutions. It is easy to turn on an app or the setting which won't let you text while driving. I think it makes a good ending of this sort of essay to encourage the reader to use that solution for their own phone use.