the traffic signal has been operating off and on for over a year and has been moved as they finish one area and go on, that's why we can't remember exactly ... but if it isn't before Paauilo, it's certainly before Paauhau.
In September, they'll still be fixing SOMETHING as they never stop fixing the road; they just move along it. The amount of delay depends on how much traffic is trying to get through, which varies highly.
I'm confused now you mention Paauhau, as I thought we were talking about HVC in Paauilo? The two are maybe 10 minutes apart on the highway. I've never visited HVC so I don't know how far off the highway it is, but some of the roads around there are dirt and I wouldn't figure more than 15 mph transiting them.
I didn't know they had designated a scenic route in Paauhau, new to me. I assume it's along the Lower Cane Haul Rd? Lovely ocean views in that area. Figure going slow, 20mph maybe, as it's not scenc if you drive fast ... call it a 15 minute detour for 4 miles?
The trip from Hilo to Honokaa is only 40 miles, but some of it quite winding. It goes through a number of small communities where speed limit drops to 35mph. Police cars often sit in these places and watch for people who don't slow down, so I obey the speed limit pretty strictly. Although I admit to going 65 in the occasional straightaway ... but 55 is the legal limit.
I'd say an hour to Paauhau from Hilo, not 90 minutes. Kind of stuns me to say that, as less than 2 years ago I typically made it all the way to Waimea in an hour.
This must seem frustrating to you that you can't get a tight estimate. The thing is there are too many variables, like getting behind a slow vehicle that you can't pass, having a traffic accident stop everything up, the presence of more trucks or buses that day, road work, weather ... so I always pad the time with an extra half hour just in case, then I'm happy when I make good time.
So what is the scenic route supposed to be like and who is calling it the scenic route? The Onomea scenic route has official highway signage, but I've never noticed signage for a Paauhau loop.