The speed signs are like a serving suggestion on a cereal box; no-one really puts sliced strawberries on their cornflakes.
To be fair, the variable speed signs were blacked out for the first 20km.
Don’t think that reckless driving is the norm. People drive to conditions. When the road is good and clear they go fast. If there is a traffic jam ahead, they flash their hazard lights. (But there’s too much overtaking on the left for my liking.)
And don’t think that drivers are impatient. Only taxis have functioning horns as far as I can tell.
The Electronic Toll Collection lanes at the tollbooths requires slowing to 20km/h, which is only slightly faster than paying by coin. (HINT: Places coins between index and middle fingers. Drop into hand of toll collector. Take receipt between thumb and ring finger.)