Mountain road trip

This weekend we completed the break-in period for our 2010 Prius, and wanted to see what the car could really do. So we loaded up the new car with 2 adults, 2 teenagers, the dog, and all our luggage, and headed out for our first mountain road trip: to Rocky Mountain National Park.

I haven't seen much first-hand information about mountain driving in a Gen3 Prius, so I thought I would describe our experience. We have a plain vanilla (actually winter gray metallic) trim line 2, with factory tires and nothing special on it. We filled the tank with regular unleaded, 85 octane, filled our tummies with Starbucks, reset the trip meter, and off we went!

In normal driving we keep the car in Eco Mode, which works fine when tooling around close to home. We left our home in the Denver suburbs, at 6500 feet elevation, passed through downtown Denver at 5300 feet, then headed up Interstate 70. We switched into Power mode at Golden, about 35 miles into the trip, when the Interstate really starts to climb.

We were very impressed with the car's power. Climbing the 6-7% grade on I-70, we easily sped up from 65 to 75mph to execute passing maneuvers. After exiting at US40 we climbed to Berthoud Pass at 11300 feet. Again, even at the higher altitude we easily passed people at 75mph on grades of around 10%. The car felt as though it could go much faster, but there's no place on this road where it's safe to go faster than 75. At the top of Berthoud Pass, our fuel economy indicator said 42mpg, the battery indicator around 75%.

The north side of Berthoud Pass is notorious for burned-out brakes on the steep winding descent. Dropping to Winter Park at 9100 feet, we tried out the different combinations of Power Mode, the B "gearshift" setting, light touch on the brakes for regenerative braking, and regular brakes. When you're in Power Mode, the computer keeps the engine running most of the time, even on the downhill. That means it can use both regen braking and regular compression braking. You can easily hear and feel the difference as each one kicks in. The "B" setting greatly enhanced the compression braking, especially in combination with Power Mode. We needed a light touch on the brake pedal when entering each hairpin turn. This activated a stronger form of regen braking, which was sufficient to slow the car. We used the friction brake only once on the descent. On arriving at Winter Park, the brakes didn't feel hot at all.

The Rockies are criss-crossed with 4WD trails to all sorts of interesting places, and we have camped at many. Some of the trails are smooth enough that a careful driver can bring a 2WD car. Rollins Pass, above Winter Park, is one of these. So up we went. The primitive road is rocky in places, steep in places, muddy in places, sometimes all three. The climb was really easy for the Prius, which hardly seemed to be breathing hard even on slopes of 20%. Here's our Prius at the summit, 11660 feet in elevation. The fuel economy indicator said 41mpg. We did lightly scrape the bottom in a couple of spots, but not hard enough to do any damage. The skid plates underneath did their job well. The wildflowers were gorgeous.



We descended to Granby at 7900 feet, then up Trail Ridge Road to the high point of the trip at 12200 feet (one of the highest paved roads in the nation), where the fuel economy indicator had risen to 44mpg. Trail Ridge Rd is limited to 35mph and that probably helped the gas mileage.

Down to our hotel at Estes Park, 7500 feet, then up the next day to the Lake Isabelle trailhead, near Nederland, at 10500 feet. Again, no problems, a very enjoyable ride with the air conditioning blasting the whole way with outside temps in the 80s. At the trailhead the fuel economy indicator said 44mpg. The trip back to Golden is very rugged with steep ups and downs and sharp curves. The Prius was rock-steady in the turns, like it was on rails. At Golden we switched back to Eco mode for the trip home.

Overall the trip was 357 miles with average fuel economy of 48mpg. We used 7.8 gallons of gas, or 2/3 of a tank, for $18. We made the car work hard, but never had to floor it, never had an engine ping, never a complaint from the brakes or battery. Other than the bicycles, we were probably the least polluting vehicle in the park. Great car.

 

hobbit, I just noticed this great article you wrote awhile back: http://www.techno-fandom.org/~hobbit/cars/b-mode.html. Have you thought about updating it for 2010, taking Power mode into account?

 

Thanks. Yes, it does seem to get blown around in the wind a bit. I-80 would be a good test.

 

It did go all the way to the top, but I don't remember it being a different color from the rest. If it was, I didn't notice.

 

Santiam Pass? I love that area.

 

I checked this out yesterday coming down from the mountains. The top bar is the same salmon color as the "PWR" label, when the headlights are on. Turn the headlights off, and the top bar is the same color as the others. Oncoming traffic thought something must be wrong, flashing my lights like that!

And a bonus: if the battery indicator is at the second-from-top bar (top bar dark), the second-from-top bar is about halfway between the salmon of the top bar and the greenish of the rest of the bars. Again, only when headlights are on.

On this trip I took I-70 to Frisco, then over Hoosier Pass at 11,500', then home via US 285. I used Eco mode the whole time and got 51.1 mpg. I didn't have any problems climbing or descending in Eco mode, except for having to push the accelerator farther.