Comparing Karangahape Gorge to the Waioeka Gorge

Karangahape Gorge is only 3 km's long while Waioeka Gorge is 39 km's long.
I believe that Karangahape Gorge has much more local traffic using it for short journeys than the Waioeka Gorge. This makes any time difference negligible between 80 and 100 kmh for a particular short journey. Most journey's through the Waioeka Gorge are longer.
The amount of traffic (number of vehicles / day) in the Karangahape Gorge is much higher than the Waioeka Gorge.
Because of the closeness of the larger population centres (close - Waihi, Thames, Paeroa, a little further away - Hamilton, Tauranga, Auckland) the skill levels of drivers in the Karangahape Gorge is arguably lower than those people that set out to drive the 150 km's between Gisborne and Opotiki using the Waioeka Gorge. People that drive in the country are used to winding roads much more than urban area only drivers.
If you leave Gisborne by road and travel toward the BOP there is only this road to use - if you travel the Waioeka Gorge road more than once you start to learn it with every journey - I feel that there are more repeat users of the Waioeka Gorge than the Karangahape Gorge - even allowing for tourists using the Karangahape Gorge more.
The Karangahape Gorge has cellphone coverage all through the Gorge - may some of the accidents there have been caused by people talking / texting on their cellphone and not directly due to the speed limts...?
People are still having major accidents in the Karangahape Gorge at 80 kms/hr