The afternoon session of Formula 1 preseason testing was briefly interrupted Friday when a shuttle bus drove on the track. In a bizarre scene, a red flag was waved to halt testing as a white bus drove slowly on a runoff area of the track at Bahrain International Circuit.

Testing ended on Friday afternoon, with Mercedes star George Russell finishing at the top of the standings, with a lap time of 1:29.545. Prior to the action taking place this week, one of the main talking points was Lewis Hamilton's official Ferrari debut after his high-profile move from Mercedes.

F1 preseason testing kicks off on Wednesday, but how can you make sense of the lap times posted in Bahrain? ESPN breaks down what to expect.