A mailbox should be placed on the right side of the driveway as viewed from the street.
Installing the mailbox in this location means the mail carrier only has to slide to the right for a nearly straight shot to the mailbox, then has the opening of the driveway to help him/her to simply pull back out into traffic.
If the mailbox is placed on the far side or left side of the driveway, the mail carrier still has to taper over into the opening of the driveway and then swing out a bit to get up close to the mailbox.
When installing a curbside mailbox the curbside mailbox must be on the right side of the road and needs to be far enough to the curb so that the mail delivery person can easily access the mailbox to deliver the mail.
If you live on the other side of the road then you need to put the mailbox on the other side of the road with your address on it.