At 4 to 5 weeks post-op, you will Tire Easily and once your energy is gone, it is GONE.
The usual recommendation from Surgeons is NOT to drive until 6 to 8 weeks post-op, although many will OK LIMITED Daytime Driving, mostly for the purpose of getting to follow-up appointments with Doctors.
Also, at 4 to 5 weeks post-op, your Sternum is NOT fully healed (80% at 6 weeks, 100% at 12 weeks).
Most Surgeons would prefer that you NOT be struck in the chest by an exploding AirBag until your Sternum is healed. (Riding in the Back Seat is safest when traveling in vehicles equipped with Air Bags).
MOST OHS patients report / complain about how S-L-O-W their recovery proceeds with a lot of 2 steps forward and one step back kind of progress. Some (younger, more athletic, in-shape) patients, bounce back to a more active live in a few weeks but most take longer.
'AL C'