Starting from the pit lane

A pit lane start means a driver doesn't line up on the grid at all. Instead they wait at the end of the pit lane and join the race once the rest of the field has gone past the pit exit on the first lap. It's the furthest back anyone can start, behind even the drivers sent to the back of the grid.

#Why a driver starts from the pit lane

#Changing the car under parc fermé

This is the usual reason. From the moment a car first leaves the garage in qualifying, it's held under parc fermé rules, which stop teams changing parts or set-up before the race. If a team breaks those rules, their driver has to start from the pit lane.

Sometimes that's forced on them. A driver who crashes heavily in qualifying may need parts the rules don't allow to be swapped, or even a new car built around a fresh chassis.

Sometimes it's a choice. A driver who qualified near the back has little to lose, so the team may break parc fermé on purpose to change the set-up, fit a new floor or wing, or take a fresh set of power unit parts. Giving up a handful of grid places in exchange for a faster car can pay off over a full race.

On sprint weekends the rule works in two stages. Breaking parc fermé before the sprint means a pit lane start for the sprint. Breaking it after the start of Grand Prix qualifying means a pit lane start for the main race.

#Problems before the start

A car that can't get away for the formation lap, or that has to be pushed off the grid, can be taken into the pit lane. If the team gets it going, the driver can join the race from the pit lane once it has started.

#How a pit lane start works

Pit lane starters can't leave the garage until the pit exit has been closed shortly before the formation lap. They then line up in the fast lane at the end of the pit lane. If there's more than one, they queue in the order they would have taken on the grid, though any car that arrives after the 5-minute signal has to go behind those already waiting.

Mechanics can still do a small amount of work in the pit lane until 15 seconds before the formation lap begins. They can start the engine, fit or remove tyre warmers, make changes for the driver's comfort, change tyres and adjust the front wing flaps. Nothing else.

When the race starts, the pit exit light stays red. Once every car on track has passed the end of the pit lane, the light turns green and the pit lane starters can go.

#Is it worse than starting last on the grid?

Usually it costs a few seconds compared with starting from the back row, because the driver has to wait for the whole field to pass. But there's an upside: they don't get caught up in any first-corner crash, and the team has often used the opportunity to improve the car.

If a driver is starting from the pit lane, the cars behind them on the grid usually move up to close the gap, as long as the team tells the stewards in time. If the decision comes too late, after the final grid has been published, their slot on the grid is left empty.