Safety car

Cars form up behind it in running order, overtaking is forbidden, and the gaps between them collapse — a leader's twenty-second advantage becomes nothing. That alone makes it the single most consequential variable in most races.

Because pit stops cost far less time under a safety car, when it appears is often worth more than any strategic decision made before it. A virtual safety car achieves a similar neutralisation without a physical car, by requiring every driver to run to a delta time.