Downhill is traditionally the fastest alpine skiing event at the Winter Olympics.
A downhill course is designed for speed, with long sections, large vertical drops and turns that are generally more open than those in technical events. Competitors normally get one timed run, so a clean and controlled descent is essential.
Super-G is also a speed event, but it includes more turns and tighter direction changes than downhill. Slalom and giant slalom are technical events with much shorter courses and more closely spaced gates. The combined event uses results from different disciplines rather than representing one pure event type.
Actual speeds depend on the course, snow and weather. Downhill is described as the fastest alpine discipline in general, not because every downhill run always produces a higher speed than every run in another event.