After nearly five years, finally drove to the Rocky Mountains in my Insight. My 1988 CRX HF did not do well, so I was pleasantly suprized the Insight did not have much of a problem.
On I25, the hills are gradual (relatively), but occasionally considerable in Colorado. People typically drive 75-80mph and I could keep up with them comfortably. There were some long climbs that forced a recalibration. Lower gears and/or driving slower probably could have avoided this.
Hwy 34 into Rocky Mountain National Park is winding and very mountainous. Traffic or severe turns kept my driving to moderate speeds, so there were no recalibrations.
One difference on these two roads - the IMA seemed to charge and discharge differently than at sea level. At times downhill, I simply could not force a charge - was the computer safeguarding the battery? The assist mode seemed to be extended in the mountains - maybe there was some concealed charging.
I25 is relatively flat between Denver and Fort Collins and elevated at about 5,500 feet. The higher altitude seemed to improve the fuel economy, although traffic is too heavy an fast to try hypermiling.
To put it in perspective, I hypermiled a 1988 CRX HF going about 60mph about ten years ago. I made the same trip driving 75mph on the Insight. Got 60mpg both times. In August I will have to hypermile and see if 75-80mpg can be done.
Still wanted to try the most severe mountain test - westbound on I70 leaving Denver. My 1988 CRX HF could not go faster than 50 mph.
i never drove the insight on mountain roads, but when i took my 93 civic si hatch vtec up to the rockies, it was pulling quite hard.. i can barely keep up with the 4x4's in front and in a few instances, i had to climb on first gear. yes, very steep. and some parts, they dont allow trucks up either.. this is the rockies up in canada..
I live here in Colorado, and just moved from Boulder (north of Denver) down to the Springs. I've driven from Limon to Aspen, as far north as Steamboat Springs and as far south as Pueblo in my 2000 (green) Yellow Insight.
On the climb via I-70 from Denver to Genesee (the 'front range', not the continental divide) at 5-6% grades the battery runs down pretty fast and I end up in 3rd to keep up with the 60-65mph speed of the highway. The car will recharge almost completely on the coast down to Clear Creek (a 7% grade) and then I can stay in 4th until just about before Idaho Springs, at which point I have to go to 3rd to stay at 60-65mph with the IMA flipping between charge and boost depending on the grade (charging on the 4% climbs, boost on the 5% and higher inclines). I have to slow down to 50 in 2nd gear just before the Eisenhower tunnel (at about 12,000 ft above sea level).
Overall MPG for a round-trip between Boulder and Steamboat Springs - a whopping 68MPG, mostly acheived on the return leg coasting down from the Eisenhower tunnel to Denver.