Today's Australian Grand Prix will be a milestone – the first Formula One world championship event since mid-race tyre changes were outlawed at the end of 2004. In certain circumstances, however, replacement tyres may be fitted. Here, Michelin motorsport director Pierre Dupasquier addresses some of the key questions thrown up by the latest regulations.

In what circumstances may an F1 driver make a mid-race tyre change this season?
Pierre Dupasquier: "Unless the FIA stewards permit a change because of fluctuating weather conditions, drivers may only replace a tyre if it is damaged for reasons beyond his or his team's control – if he sustains a puncture after running over somebody else's accident debris, for instance, or is hit by another car. It will be up to the race stewards to determine whether any such change is legitimate."

If a tyre change is approved, will the driver be permitted to take on a full set of fresh rubber?
PD: "No, he may only replace the tyre – or tyres – directly affected."

What happens if tyres become so worn out that it would be unwise to continue?
PD: "At the moment, the rules dictate that any car thus afflicted should be withdrawn from the race. Personally, I would like to see cars being fitted with replacement tyres and sent back out in such circumstances. It is better for the spectators to keep as many cars in the event for as long as possible – and it also enables tyre companies to accumulate extra data that could help them combat excessive wear in future."

Who makes the final decision about mid-race tyre changes?
PD: "That is down to the manager of the team whose car is affected. If we notice a situation we believe needs addressing, we will advise the team accordingly. It is our responsibility to make teams aware of developing tyre situations, but theirs to take any final decision. Nobody is going to send a car back onto the track if its tyres are so worn that it would be unsafe to continue. That's just a matter of common sense."

Typically, what types of check will Michelin's technicians make during the course of a grand prix?
PD: "Visual, mainly – you always have to be alert to potential tyre damage – but we are also able to keep an eye on pressures using the latest on-board sensors. These provide extremely reliable feedback."