The FIA's race director and safety delegate, Charlie Whiting, explains the new sporting and technical regulations for 2012.

Why has a four-hour total time limit been put on Grands Prix?
Last season the race in Montreal went on for four hours and four minutes. A race really should not go on longer than that. Should four hours elapse during a future race, drivers will receive a signal telling them they have one more lap before the chequered flag.

Race stewards will now be able to investigate an incident without first reporting it to the race director. Why is the system changing?
In the past stewards might see something suspect and alert the race director. He would look at the incident and request the stewards investigate. It was a process that consumed a lot of time. If they identify something worth investigating, there's nothing wrong with them taking a look and then giving the race director an opinion. It should make the process less cumbersome.

Drivers are now instructed to not deliberately leave the track without good reason. Why?
We've seen drivers taking shortcuts on in and out laps, either to save time or fuel. We could put up barriers to stop them exploiting short cuts but it usually looks stupid! The rules say the drivers should use the track. If they don't, they will need to justify their actions.
It also follows that safety will be improved as other drivers are more likely to know that a car has left the track for a good reason.

The 'one-move' rule on defending a position has been reinstated. Has there been a problem with dangerous blocking in the last few seasons?
This isn't really a new overtaking rule, rather we've put into the regulations what was an unwritten rule. A driver can make one move only to defend a position - but when that driver then moves back onto the racing line to take a corner it can be construed as a second move, which is not allowed. It's a matter of deciding to what degree resuming the original line is acceptable. We don't want to get into silly arguments about centimetres so we've decided the defending driver must leave at least one car width on the racing line otherwise he will be judged to have made a second move and penalised accordingly. We need to have drivers giving each other space on the track - otherwise we risk dangerous collisions.

Previously cars needed to pass crash tests before racing. Now they have to pass before testing. Why?
Safety cannot be compromised. It is indefensible to have drivers testing cars in the winter that haven't met the safety standards we demand for a race. The teams resisted this for quite a while, telling me it would be impossible to get the crash tests done before the first test. It came as no great surprise that nearly everybody managed it.