Sounds like the car you drove was defective. I have an auris which is mechanically identical to a Prius. I have not driven those exact roads but I have never s

Sounds like the car you drove was defective. I have an auris which is mechanically identical to a Prius. I have not driven those exact roads but I have never struggled going up hills and it will hit 60mph from a standstill in just under 10s, so with a rolling start of say 20-30 getting onto the onramp you are at 60 or so in 6 or 7 seconds. If your onramps are so short that you can't drive for 6 or 7 seconds before merging, then I guess that is a different problem.