Hello, There was an Hours of Service change on July 1st 2013 which requires a driver to take a 30min break within a 8 hour work period. I have provided the regulation below.
"After June 30, 2013, however, driving is permitted only if 8 hours or fewer have passed since the end of the driver's last off-duty break or sleeper-berth period of at least 30 minutes" http://www.fmcsa.dot.gov/rules-regulations/administration/fmcsr/fmcsrruletext.aspx?reg=395.1
Hope this information helps, please let me know if you have any other questions.
Have a great day!