Ok - odd ball question. I went to the dealer to test drive one, and wanted to run it up 285 as far as Turkey Creek (silly me, I wanted to see how it would handle a hill, seeing as we live in Colorado and all).
They swear their insurance will only cover driving int their own little lap track. As I am looking at a business use that will include occasional "hilly" runs, I need to see and feel what it is I am buying. (Currently, I am using Suzuki X-90's, but they are getting harder and harder to find).
You may just have to rely on others' advice because the dealer may not be willing to 'let go' of a test smart for that much distance. I can tell you that mine holds 5th gear doing 60 on a moderate hill, and if I drop under 50MPH I have to downshift. If I drop under 45MPH I may not get back into 5th gear until the hill crests. City hills are annoying that way, so I just manual-mode it into 4th on those.
I don't know how it handles CO hills though... and am interested in how it handles Pike's Peak. I once took an overloaded UHaul and towed my car over Pike's Peak... poor, poor UHaul... I bet it was never the same.
I can tell you about hills, as am from Ouray, Colorado. You will have to down shift on pretty much every hill, as there is very little torque. Down shifting is not a bad thing, but a fact in a Smart. On the 70, that being the Vail Pass, I was shifting all of the time. Auto mode will not do.
Alustiza, what speed were you able to maintain over Vail Pass? I think I was wrong originally and that's the one I towed the car over... it was a tough one for most cars, and 18 wheelers especially. It's so steep that everyone just expects someone to be going 40 uphill and 120 downhill. I'm guessing the engine braking in the Smart is better than with an auto transmission, right?