which takes me back to my original comment then, offer those who don't want to work weekends or late nights a slightly lower pay, and give those who do want to a slightly higher pay. there'll be plenty of people who will be happy to be scheduled on a sunday and get a day midweek off, so you have a pool of people who will cover the more unsociable and quieter hours as well as evenings and weekends, maybe even offer them fixed early or lates (better sleep pattern = better drivers?), then you also have a pool of people who are scheduled to work during the day and week, when you have 'peak' loadings. If I could be guaranteed permanent early's I'd be fine, Im happy getting up early, but struggle to stay up late and still be useful.