Simplify the following text for a Grade 10 native English-speaking person.
Original: Generally the event 's duration ( commonly one hour ) is shorter than that of a traditional road race -- which can last many hours , sometimes over the course of several days or even weeks , as in a Grand Tour .
Simplified: Often a criterium lasts about one hour , which is shorter than that of a traditional road race -- which can last many hours , sometimes of several days or even weeks , as in a Grand Tour .