Tips for highway driving?

Absolutely! My safety, and that of other road users, is far more important than a minor hit to fuel economy. When I need to get up to speed in a hurry, I step on the gas and ignore the eco display and the howling of the engine - the car is designed to do this.

In metro New York City, and particularly on Long Island, the ancient parkway system was not designed for modern traffic. Some of the ramps on Northern and Southern Parkways, for example, feature a clover-leaf curve on the entrance, followed by a short straight section for merging - which is also the exit ramp. Here's one of the worst examples, but there are many more. When entering the parkway, if you don't step on it as soon as you hit the straight stretch, you'll find yourself parked at the end of the entrance lane waiting for a long break - which never comes.

The exit ramps are not any better - here's my local exit when I'm heading east on Southern Parkway heading for home (traveling left to right on the map). That hairpin ramp is posted for 15mph, and if you hit the curve too fast you'll find yourself on the grass. So to exit the highway you have to first merge with the entering traffic, then get from 60mph down to 15mpg in the space of about fifty feet. No time for coasting or gentle braking here!

So what I'm saying is, don't worry about what your Prius is doing - deal with the traffic conditions as you would in any other car. Your overall fuel economy will still be far superior to that of almost every other car - according to Fuelly, after over 7000 miles of this kind of driving, I'm still getting close to 50mpg. And that's with keeping up with traffic at 60mph on Long Island (if the traffic is actually moving!), and 70mph or more on the mainland highways.

 

I have not driven the Prius C but coming from Gen2 (similar ICE), I think the red zone means it is non-optimal BSFC. The difference between the optimal and non-optimal is about 5-10%, so don't sweat it. Get up to the speed and maintain at the optimal efficiency.

 

I have found better mileage is achieved getting up to speed briskly than in granny mode.

RAL

 

Meh, only on a long hill. I would much rather prefer to have 60-65 mph before I start going uphill, and then keep it above 55 mph the whole time. I can't be arsed to poke around going up a long hill on a highway...the longer it takes the lower my fuel economy gets (unless you're fighting air friction and going really fast).

P.S. My previous 100+ highway trip was 60.0 mpg, with the AC on.

 

I don't use the red zone often, but probably should more. When I have, it was usually on an uphill highway entrance ramp, or a short merge zone. Another recent one was climbing a steep hill from a stop on back country roads - someone was behind me, otherwise I would've just crawled up.

My only tip is to build up some speed before an upcoming hill and let the car slow to a reasonably safe speed as you're pushing it up. I wish cars came with intelligent, road-aware cruise control that could anticipate hills, or that fewer people would get pissy when I go slower up hills.

 

I almost always get into the red zone when pulling away from most stops and lights multiple time per day! I don't stay in it long, but long enough to get up to speed.

 

This car sucks on highways. I drove 2000k miles in 2 days. 70 mph with about 400 lbs going 70 MPH I got 41-45 mpg.

75 mph my mpg dropped to 37-40.

keep it under 65 and you'll stay in the 50s

 

Most of my exits are long so I manage to stay out of the red zone for the majority of my freeway entrances. Every once in a while, I encounter a short merge or when I need to merge onto a fast moving lane, I don't hesitate to use the red zone. It's that or risk causing road rage behind me. I'll take the fuel economy penalty.

 

Yup - short (length-wise) cars don't do well at higher speeds. Few other cars will get 37-40 mpg at 75, but the ones that'll come close are longer. With 150-300lbs, I've gotten over 50mpg at 65. I usually stick to ~55-62 mph. I've started taking non-interstates because they're more scenic/interesting and I enjoy them more, and the max speed limits are 55, with some 25-40mph zones for EV/gliding use.

 

Ditto FTL, if I stayed out of the red zone driving in NYC, I'd get cut off 50 times a day. I use it when I need to, but if I can avoid it I will.

I am much more aware of it now though, its been a little over a month since I bought my C. In my old car I was probably "in the red" a lot more.

 

Don't look at the red zone when entering a 4 lane hiway. Just get up to speed and set the cruise. You mileage will come up when you travel a few miles. I bump my cruise off on a long uphill climb but do gather some speed before approaching it. Trying to stay out of the red zone is difficult, unless you dont mind getting run over. I find that this car is super at 65-70 mph on hiways, compared to most. We did a 1700 mile trip shortly after buying our C. Was almost all interstate. Got over 51 mpg calculated. I did run a couple of mph under speed limit if not much traffic but I also ran over posted speed limits when I needed to. My thinking is anything north of 40 mpg is great mileage in a car. I have had motorcycles that did not get this mileage. The C will get the advertized mileage with no effort by the driver. More when a little attention is paid to the driving habits.
Dan