Qualifying commences at 11am local time on Saturday. Each car is given a single, four-lap run to set an average speed – and will go in an order selected by random draw on Friday night (see below).
When every car in the qualifying order for Saturday has had at least one chance to qualify, teams may choose from two lanes at the end of the pits for subsequent attempts.
Cars in the Priority Lane (Lane 1) must withdraw their qualified time but get priority access to the track ahead of Lane 2. That second lane is for cars that have already qualified and want to try to improve their position but choose not to risk forfeiting the speed average they have already set.
When the gun goes off at 5.50pm, positions 13-30 will be set, and those drivers will not re-qualify on Sunday. The 12 drivers who will contest the front four rows of three, and the four drivers who will squabble over the three slots on the last row will now have been defined.
On Sunday, May 21, from 11.30am, the dozen drivers still in the fight for pole will get a one-hour practice session, and this will be immediately followed by an hour's practice for the desperate quartet due to battle over the last row.
Source: Autosport