Sector time

How the timing works

Each F1 circuit has two sector lines (often called "split points") in addition to the start-finish line. Crossing each line triggers a timestamp from the FIA's timing transponder system. The three resulting splits are the sector times for that lap^[1].

Sector boundaries are not always at the same percentages of lap length. Each circuit's sectors are defined by the FIA before the race weekend and remain consistent across all sessions of that weekend.

Purple, green, and yellow sectors

When the broadcast shows sector colour coding:

• Purple: the fastest sector time of the session so far. Anyone who sets a new fastest sector "goes purple".
• Green: faster than the driver's own previous best for that sector, but not faster than the session purple.
• Yellow: slower than the driver's previous best.

A lap that goes "purple-purple-purple" (purple in all three sectors) is the session's optimal hypothetical lap. Note: this is not always the same as the fastest actual lap, because no single driver may have strung together all three best sectors in a single lap^[1].

Why teams analyse sector times

Sector time vs lap time

A lap time is the sum of three sector times. Sector times are useful for analysis; lap time is the unit of competition.

The strongest commentary observation about a session often uses both: "Hamilton was purple in Sector 1, lost three tenths in Sector 2 traffic, and recovered most of it in Sector 3."

Related

• Delta time
• DRS