Road bicycle racing is the cycle sport discipline of road cycling, held on paved roads. Road racing is the most popular professional form of bicycle racing, in terms of numbers of competitors, events and spectators. The two most common competition formats are mass start events, where riders start simultaneously (though sometimes with a handicap) and race to set finish point; and time trials, where individual riders or teams race a course alone against the clock. Stage races or "tours" take multiple days, and consist of several mass-start or time-trial stages ridden consecutively.