R slower than L knee. Generically it may take longer to be able to drive safely after right knee surgery since this is your driving foot. Once you are off daytime narcotics, can efficiently get into and out of car seat, and have painfree and normal reaction time moving from gas to brake pedal, you are probably safe to drve. Many state have something like our state's "impaired driver law". Check with your dmv.
Depends. This depends on the limb that is injured and the other structures repaired. If your non-driving leg undergoes surgery, generally one can drive when able to get in and out of a car and when not adversely affected by pain medications from surgery (2-14 days). For your driving leg, it depends on the restrictions pertinent to your individual repair and must be discussed with your doctor (7-28 days).
Laws vary by state. Always discuss postoperative activity allowances with your surgeon. Many states have basic impaired driver laws to help guide this decision. Several basic parameters can help. You should be off daytime narcotics, able to safely and efficiently enter/exit the vehicle, and your reaction times to move your foot from gas to brake pedal should be normalized. Right knee surgery will require more time.
Varies. To begin driving you should be a safe driver. This will vary from days to a few weeks. Naturally, you cannot be under the influnece of narcotic/pain meds etc. You should have good range of motion without pain and reflexes to be able to respond to a challenging situation and jam on the brakes if necessary. If your acl is done on the right knee then it could take longer. Start therapy in 1-2 weeks.