Since gravel allows water to flow through it easily and into the ground the gravel is pervious.
Although the rocks themselves are impervious the gravel when spread out allows the water to flow freely through it to the ground and is used in areas where drainage is necessary.
So if you have a gravel driveway the gravel driveway is pervious also because water doesn't just stay on top of the gravel driveway because it flows through the gravel and into the sand beneath it.
If you have a concrete driveway or asphalt driveway that would be impervious because water cannot flow through it and would remain on top of it.