On all postal routes, move the mail boxes to the same side of the street. I watch the mail carrier go up my street, stopping at each house and then back down the other side stopping at each house. What a waste of time and fuel.
Moving the mail boxes could be performed by a public service group like the Boy/Girl Scouts or have the prison work groups move them. The Postal Service could provide standard mail boxes/posts or provide a $25 one time stipend. This doesn't have to be a major undertaking, just start it, promote it and show the savings to the public and I believe it will slowly become the norm. The Postal Service could get creative with mail box styles, maybe have a design contest for multiple boxes to be shared by neighbors. Even if only a few people move their boxes to the same side of the street, that's one less stop for the mail carrier. Also, this makes less stops for the newspaper carriers, since their boxes are with the mail box.