normal enduros...
normal enduros have a time keeping format where after the start the riders must maintain a speed average, usually 24 MPH. If you arrive early you lose more points than arriving late so you are keeping track fo time all the time. In a restart format the "check in" are announced in location and you are free to arrive to them early and you cannot leave until your minute is announced-then race to the "check out" and your time is scored and you are free to travel to the next "check in." This type even eliminates the tricky time keeping and no time keeping equipment is really needed, just ride to each section and race the sections.