Complex sentence: The Sunday between practice week and race week is known as "Mad Sunday" where many members of the public ride the course, the mountain section from Ramsey to Douglas is one way with speed limits for this day.
Split into simpler sentences: The Sunday between practice week and race week is known as "Mad Sunday" where many members of the public ride the course. The mountain section from Ramsey to Douglas is one-way with speed limits for this day.