I don't know what I would do in this situation probably the same thing. However couldn't you just slowly move your cars past them and eventually break through? People will move I don't think there were any martyrs out there willing to lose their life if traffic refused to stop. So glad I don't live in California.
http://www.aol.com/article/2014/12/09/protesters-block-highway-stop-train-in-california/21004795/?icid=maing-grid7%7Cmain5%7Cdl3%7Csec1_lnk3%26pLid%3D578366
http://www.aol.com/article/2014/12/09/protesters-block-highway-stop-train-in-california/21004795/?icid=maing-grid7%7Cmain5%7Cdl3%7Csec1_lnk3%26pLid%3D578366