Variable fuel pricing

One of the big supermarkets are in talks with a danish company to introduce variable fuel pricing at peak times, so the school run and bank holidays could see prices increased by as much as 2p per litre , this system is used in the us and some European countries, but who decides what are peak times? What about school holidays when people are going away, will the prices rise for a week, or six weeks when the schools are off? Good idea? Or not?
The technology uses artificial intelligence to monitor peak times so I guess it will decide what constitutes "a peak time"