Is it possible to predict when roads will have less traffic? I'm planning a two day trip down the UK country roads. I'd like to time and plan my route so that I'll have a pleasant ride. Is it possible to tell which days of the week would see the least traffic? I'll be cycling from dawn till late afternoon on both days.
Generally speaking, Saturdays and Sundays are quieter than weekdays.

The Department of Transport collects various statistics on road use. This table (TRA0307) shows average traffic by time and day of the week.



There's also this table (TRA0306) which shows average traffic by day for different road types and different vehicles.



Finally, there are statistics for average annual traffic on every major road in the UK. There's an interactive map here.