Surely you noticed that the track was slanted at the bends? These are called banked curves.
If you had watched F1 racing before, you should know that F1 race tracks are flat. The race cars have to slow down (F1 fans love to watch and hear the acceleration) when they go into the curves . If they do not, the required centripetal force (mv2/r) will be too large. The tires just do not have enough grip to produce the required amount of friction.
NASCAR race cars do not slow down when they turn. Banking allows the cars to utilize the normal contact force that the track surface exerts on the cars to provide the required centripetal force. In fact, at particular speed and angles, the cars can negotiate the bends without the tires providing any sideway frictional force at all. This allows NASCAR to turn at full speed, which NASCAR fans love.