Denver to Breckenridge and back, via I-70

Last weekend I finally got around to taking the Prius to Breckenridge and back. I took I-70 there and back which involves several long climbs with a few descents mixed in going from an elevation of we'll just call it 5,539 (elevation at my house in Denver) to 11,158 feet at the Eisenhower tunnel. (this isn't completely accurate, due to traffic I jumped off and took a minor short cut I know that involves a steep down hill to clear creek then you pop out on US 6 which reconnects with I-70 a short time later bypassing a congestion point) You then drop to about 9,035 ft in 12 miles to Dillon / Silverthorne. I believe the steepest grade along this route is 6% but I'm not sure where it hits that or how long it maintains it. From Dillon / Silverthorne you continue for a few miles to Frisco where you turn south and head up a gentle grade to Breckenridge. My numbers are not accurate as I spent about 45 minutes sitting with the car kicking the ICE off and on in a parking lot while the wife did shopping (ugh). But with that in there the car figures I got 55 mpg there and back, which I'm pretty happy with.

I don't know if it's an issue in the Prius but the Volt's have "mountain mode" because if the battery runs out on you while climbing a steep grade you have very little power to continue. Watching the battery meter fall and knowing I had a steep climb ahead I had that in my mind so I used PWR mode thinking it may help. No clue if it did or didn't. I had no trouble keeping up with traffic, I was surprised that I was passing people without much drama, including a new Forester which I had test driven prior to buying the Prius.

I used the B position on the shifter for the first time on this trip. When I took a small alternate route it parallels I-70 briefly then with a slight turn drops away sharply. That's when I hit B mode. Traffic on I-70 was stop and go right there and a second or so after hitting B I hear some ricer with his engine screaming. I thought "wow someone is playing Tokyo Drift" and I was checking my mirror to see if he was on my road or I-70. Took me about the count of 5 to realize that it was the Prius ICE spinning to beat hell. Very strange feeling for me because the motor is racing but there is almost no engine braking to speak of. The rest of the way up to the tunnel was just boring driving, I used the radar cruise most of the time. It really isn't good on these passes though because you're constantly in and out of the different lanes trying to maintain your speed and I cannot judge when the cruise is going to hit the brakes. I also leave it in the farthest following distance setting so if I do time it right changing lanes before the car hits the brakes on me, invariably people in the lane I just went into are sneaking by through the gap the radar system would have left and if they're not going fast enough the radar then hits the brakes on me. So yeah, it's great when you're staying in a lane, but not so great in the mountains.

Popped out of the tunnel to the steep grade down to Dillon / Silverthorne and I was still in the cruise but I put the shifter to B. It seems that doing so disabled the cruise system. I could not adjust my set speed up or down. So I figured I'd just coast down in B and let the engine braking work. I will say that engine braking does not work. At all. It makes a lot of noise but on something around 6% you still gain a lot of speed. From 50 mph it coasted up to 83 mph and that was at the bottom when the grade began to level out, I think it would have continued to accelerate if I had a longer hill. Also; I am shocked at how badly the Prius handles. It is truly the worst handling car I have ever driven. I cannot even imagine how terrible a previous generation with the older rear suspension is. I mean, I get it, these things aren't sports cars, I'm not regretting my purchase, I just think that the limits of the car are pretty close to the speed limit on any given road. I didn't die while speeding down that hill but I would not have been able to control it if someone had cut me off. So that's the end of the "will B mode hold me back?" game for me, because no.... no it won't.

On the way back to Denver you have the steepest climb from Silverthorne / Dillon to the Johnson tunnel, gaining about 2,000 feet in 12 miles topping out at 11,158 ft. Speed limit is 60 mph, Prius had no trouble maintaining 65 (its what the cruise was set at and traffic was going about that so it was easy to maintain it). Near the top where the road is steepest I did floor it to see if I could gain speed and while it's not going to win any races there was still plenty left in the tank for reasonable driving. Through the tunnel, out the other side and my downhill section to Denver began. Knowing now that B won't slow me at all I left the car in D and I let the cruise do the work. It cycled between charging the battery and using the B mode to maintain speed and it never got out of hand. I'm not sure if it ever hit the friction brakes, it never felt like it did, but there were certainly times the battery was full and it was in B mode but I wasn't gaining speed so I think it was riding the friction brakes. Bit concerning because not knowing how much it is or isn't using the friction brakes I'm not sure how to judge when I think they may be getting hot. I never had any indication that they got hot however.

So get into town, I'm taking an off ramp from US-6 to I-25 cruise control is still on because I'm lazy like that. Three lanes exit US-6, 2 go to Northbound I-70 and 2 go to Southbound I-70, the middle lane can go either direction. So I'm following some truck who decides he's going North, I'm going south. He changes from the middle lane, that I'm also in, over to the left lane. When he clears my lane, the Prius begins to accelerate back to whatever my preset speed was and I begin to take the sweeper to southbound I-25. While in mid turn a car in the right lane quickly jumps out in front of me going much slower than I am, the Prius jams the brakes pretty hard, tires squeal, I'm not sure if the ABS goes off or if it's imperfections in the road or suspension I'm feeling but there's a shudder as the Prius understeers toward the shoulder. I tap the brake, I think out of instinct, which kills the cruise system, brakes let off and the car goes back to steering through the turn as I feed in a bit of gas to make the car neutral. I do end up getting closer to the car that changed lanes than the cruise would have permitted but I don't feel I got unreasonably close. I am not saying that this was a near accident and my Prius tried to kill me because I still had plenty of shoulder left to work with the tires did not lock up and it just under steered which is preferable to lift off oversteer, but I can see where that type of thing could freak some people out. I was probably driving faster than the recommended speed for that corner, but it wasn't THAT fast. The tires seemed to run out of traction much sooner than I would have expected even for a gas saver tire but that might have been more to do with the car jamming the brakes so hard. Maybe it thought we were going to crash and was in maximum "save the idiot behind the wheel" mode? Either way, the suspension was not doing me any favors. The touring model may have done better with the 215 section width tire over the non-touring 195 but I don't know if that's enough to overcome the suspension design (I'm trying hard not to say "issues", I keep telling myself it's not designed to be driven at the limit). Either way my big lesson is do not exceed the speed limit. I feel like I missed a great opportunity to bend my new Prius with this incident, I really need to work on being more aware of how slow the Prius likes to be driven. I think this also demonstrates that the next generation of radar needs to somehow be aimable,so it can track your intended path through a turn better. This would allow it to have spotted the merging car sooner and it needs to be a bit less rigid when it comes to that following distance. Yeah if the car is pulling away from you when it cuts out in front the cruise doesn't seem to care but if you're reducing that distance it gets on the brakes hard. Radar cruise is already better than I thought it would be and I cannot imagine ever buying a car without it, but I really need to get out of the habit of using it through tighter turns and when I know I'll be passing people.



TL;DR version: Prius has enough power to keep up with traffic even on mountain passes, Prius is not a sports car, at only 55 mpg I am still not good at hypermiling