Kaika,
A neighboring town in Michigan started doing four days a week a year or two ago. I believe that they go Tues-Fri (could not have Friday off as that is football night.) It not only saves gas on transportation, we're in the North, and that means that the school only needs to be heated 4 days. It worked out very well for them. I know their school day is longer, but I do not recall how much longer it is.
Parents aren't as eager to make this change, it means finding day care for the kids one day a week.
Here's MI link approving all schools for four day weeks.
http://cw.mariancollege.edu/bstucky/...mp;TOPIC_ID=90