The worst hill I've had with my Insight, was a drive north up I-15 to I-90 and then west on I-90 through Montana. I had just built up speed to go up Lookout Pass with a full state of charge and was downshifted into 3rd gear to help maintain battery / speed for as long as possible.
Then a big rig decided to pull into the left lane to pass another semi. Simultaneously, there was road construction ahead and the 2 lane road narrowed to 0 lanes, with a single detour lane taking us over to the other side of the freeway.
Due to the big rigs floundering and trying to decide who would go first, they both ended up stopping, along with the rest of us. Finally they took off, and merged into the construction detour and were creeping ever so slowly, gradually increasing speed.
Unfortunately for me, the portion of the approach to Lookout Pass they stopped on, was probably the steepest portion possible, and even in 1st gear, it was difficult to take off, and consuming a substantial amount of charge trying to build up speed, but not quite enough to get off battery.
Then the battery was completely exhausted, and torque was greatly diminished and the big rigs pulled ahead as I slowed to around 10 miles per hour and everyone else behind were honking as I was holding up traffic, but there wasn't anything to be done... there wasn't even a shoulder to pull off and do an idle-recharge.
Eventually we crept out of the construction detour onto the main highway and I quickly got onto the shoulder and was able to gradually build up speed to where the engine could hold its own.
This is the ONLY time I've had a problem with climbing hills.
Other than that, I take this car all over the desert mountain region and haven't had any problems.
