If you have a flat tyre on your car then there are different things that you can do depending on where you are when you notice it, below is a guide to what to do in different scenarios.
If your car is parked up and you come to it and notice a flat tyre then the first thing to do is inspect the tyre for any obvious signs of damage or any foreign objects that could be lodged in the tyre, if you cannot see any then it may be that the tyre just needs more air as things such as changes in temperature or the car being stood still can cause the tyre to need inflating.
If you notice that you have a flat tyre whilst driving it is likely that you will notice that you are unable to accelerate as quickly as usual and you may feel the car pulling to one side. As soon as you notice this you must pull over to the side of the road carefully as soon as it is safe to do so. Driving on a tyre that has a puncture can be very dangerous so you must do this very carefully and ensure that the vehicle is in a safe position as far off the road as possible.
If you are on the motorway or dual carriageway then you must call your breakdown company as it would not be safe to attempt changing a tyre at the side of such a fast busy road and in doing this you could cause a very serious accident.