For domestic operations, US airline pilots are limited to:
16hrs maximum time on duty
8hrs flight time per duty period
30 hrs per 7 day period
100 hrs per calender month
1000 hrs per calender year
Additionally, pilots must recieve one 24 hr period free from company duty every 7 days.
A normal rest period is 9 hrs but is reduceable to 8 hrs provided a compensatory rest period (longer rest) is scheduled immediately following the reduced rest.
At my company (and most others) your rest period begins 15 mins after block in, completely unrealistic. 15 mins after block in the crew is still securing the aircraft or, at best, walking to the curb to meet the hotel van. Take into account the 20 min. wait for the van to show, the 20 min ride to the hotel, eat, shower, etc. you would be lucky to get 5 hrs of sleep.
Oh yeah, I almost forgot, your rest period doesn't end until 1 hr or :45 mins prior to scheduled departure time. That doesn't leave alot of time for sleep in those 8 hr rest periods.
Our pilot contract does not allow the company to schedule reduced rest periods. It also limits the scheduled duty day to 12 hrs. However, if your running late, you can end up on a reduced rest and/or on duty over 12 hrs.
Ask any pilot and they'll tell you that whoever came up with these rest requirements never had to work under them.