HOS (hour of service) are simple. You have 70 hours you can drive or be on duty in an 8 day week. Any time you are driving, fueling, shipper, receiver, inspections are doing anything related to your job it has to be logged as on duty. After the 8th day the hours you worked on your 1st day come back, are added back to your unused hours if any, these hours that come back most call recaps or rollover hours. Most drivers drive on there recap hours rather than opting for a 34 hour restart. It takes a bit more thought, but you actually get more hours per week if you dont take a 34 hour restart, there are a couple exceptions but only a couple. You have to have an insane run and cheat a bit on your logs to get more from a 34 restart than from running on your recaps. The basic reason for this is when you take a 34 restart, you get 70 hours but the recap hours you got back in two days of sitting dissapear (deleted in order for your 70 to take effect) and you will not get any recap hours coming back on your logs untill after your 8th day. You can only legaly drive for 11 hours per day within a 14 hour period, if you have 11 hours on your 70 to drive. Remember from above about fueling your required inspections ets.. taking away from your 70. Once you log on duty your 14 hour clock cannot be stopped for any reason even if you dont drive. Unless you use the split sleeper birth provision, which would take me a full page just to explain.