What am I doing wrong? Better MPG on FWY than the local HWY

Are you going very short distances not letting the car fully warm up? And if it's really cold outside that's a double whammy..... The ice "engine" runs to get and keep the car up to temp for pollution control and if your running the heater full blast as well as maybe the seat warmer the ice runs too because those drain the main traction battery so fast it has to to keep the battery from depleting.

The longer hiway trips have time to get everything fully warmed up so the ice tends to not cycle so much saving gas.

That's one theory.

SCH-I535 ? 2

 

Huh? Per Compare Side-by-Side, the EPA rating is 51 CITY/48 highway, 50 combined. You're already above EPA combined rating.

EPA estimates are NOT promises that YOU will achieve those numbers. Please read Car and Driver: The Truth About EPA City / Highway MPG Estimates | PriusChat to learn more about the EPA tests. Car and Driver: Here’s Why Your Mileage May Vary (A Lot) from the EPA Estimates | PriusChat might also be interesting.

Hint: They don't drive on a real road, but rather a dyno. They also don't even measure actual fuel use. The highest average speed in any of the cycles is only 48.4 mph.

Also, your mileage is taking a hit right now due to colder weather and winter fuel blends. See Why mileage gets worse in winter | PriusChat. It will get better as you learn the car better and when spring rolls around.

 

The majority of our Prius driving is on the inter-state. We simply get it up to speed and set the cruise-control. My wife sets it at 75, I set it at 80. We get better mileage on the inter-state then we do on back roads.

 

Local road driving was killing my mpg too- so I traded in my 2012 Five for the 2012 Plug-in Prius. Now I usually go the full weekend using zero gasoline.
Right now my charge cord is in CA being upgraded to run on 240v, so this weekend my PIP is running like the regular HV Prius- I just got back from regular weekend errands that would have been run strictly in EV mode showing 999mpg- but this morning (38deg) I got 36mpg at the end of my 7mi trip with three stops and holiday traffic. Can't wait to get my charge cord back!
In the end- just because you're driving slower on the highway, it doesn't necessarily translate into better fuel economy. Starts, stops, surges, changes in speed- all kill mpg's...

 

Beethovenite, I'd like to get 55mpg lifetime too. Wanting & getting are two different things. EVERYTHING affects FE so the goal needs to be restated.

How do I achieve the best FE I can?

Adjustments can be made to the car. If the ICE isn't getting or staying warm enough then block the grill. Inflate the tires. If the alignment is causing drag then get it fixed.

Adjustments can be made inside the car. Do you really have to blast the climate control? Probably not. I don't turn the heat on until coolant temp is 150F but I run the defrosters when I have to. I set the temp at 72 then bump it up to 74 or 75 in the winter. The idea is to keep fan speed low, Start the AC at 80 or so then adjust down. Keep fan speed low.

Change your route. Steady speed is efficient, so is lower speed, generally but there are bands. Coast, don't brake. When the car is cold you want the warm up cycle at higher speed. The ICE is going to run anyway so you might as well get some distance out of it.

For example, going to the office I turn onto our private service road to avoid a controlled busy intersection. That turn is taken at 25mph or more. I can then stay in the EV range around the building. At the traffic light to cross the street (1 block down from that busy controlled intersection) I accelerate but stay in the EV range. The posted speed limit is 15mph and employees don't pay any attention when walking into the building. I'm on electric all the way until I park in my spot. This is always good for goosing the tank's number regardless if it is full or empty.

Reverse the trip and it is different. The ICE runs through the parking lot. The ICE runs at the traffic light. I want to go faster. Why? The engine is cold. This doesn't always happen in the summer. There's a big difference between starting with coolant temp at 30F and 85F.

On the HSI screen if you stay on the left side you are an EV. When you blip over to the right the FE drops to a low number. Lighten up on the accelerator to drop the bar all the way down then reapply the pressure.

450 miles isn't much. It takes time and practice but if you try you will improve. Will you get my number, or Wayne's number, or F8L's number? Maybe. Maybe not. The competition isn't with another car or driver. The competition is you. Can you do better today than you did yesterday? The numbers will go up. The numbers will go down. Overall they will trend up as you get used to the car and the car gets used to you.

Relax & observe. There are a few videos out there that are useful,

 

What's your definition of HWY and FWY?

When I googled FWY, I got this: Urban Dictionary: fwy

 

Seems outside temp affects gas mileage more than any other non controllable item.
Heating your tush with seat warmer is much more efficient than trying to heat the cabin with warm air.....

I finally just drive mine.... Don't want to be a slave to my car... It's supposed to serve me....
If I spend extra time driving slow to save 3 mpg, it's just not worth it... Especially if I'm not having fun doing it.

The prius gets great gas mileage no matter how you drive it!

Cold & hot weather, is hard on all cars as the air runs like crazy.

SCH-I535 ? 2

 

you might need a new 12volt battery. at 65mph, the hybrid battery doesn't come into play that much as far as improving mpg's. but on side roads,it's a huge factor and if your 12v is bad, the ice wastes fuel trying to keep it charged.

 

Jim pretty much covered it and as Andrew (cwerdna) stated, it's all about your speed. The EPA test did not anticipate you driving in sub-optimal conditions at 70+mph. That is why they add the disclaimer Your Mileage May Vary.

You've also been driving on winter blend fuel which usually causes a loss of a couple mpg. Toss in cooler temps and I would say you are at least 5mpg lower than you would be in the summer with temps in the 90s (not using AC).

Like Jim so eloquently wrote, "it takes time and practice but if you try you will improve." When you get serious about learning, look to the folks in the Top 20mpg Record Holders thread. They are always willing to offer advice.

 

I get better mileage on the highway as well.

 

It's certainly fun to try and see how good a mpg you can get, but after a while it's diminishing returns. You seem to hit a curve, very easy to get 44-48 mpg, have you pay attention to get 48-52 mpg, and you have to let all your attention be distracted to get higher.

SCH-I535 ? 2

 

That depends on your driving conditions. This summer I found it very easy to get 55-57mpg without trying. I could do 63-65mpg with slower driving and some effort. It took serious work to get 68mpg+.

 

Wow, good job... I probably drive too aggressive.

SCH-I535 ? 2

 

Or maybe you just drive with different conditions or many more short trips.

Regardless, I agree it is really easy to get 44-48mpg with the Prius. Even in bad conditions!

 

I tend to cruise on the open highways in Texas 70 - 80 mph pretty routinely.... And I'm used to a fast bike, so I don't start off super slow either... Not to the floor but close. I'm in power mode 100 percent of the time.

I used to have fun milking it, but now I just drive.... It still beats the pants off any non hybrid/ev car out there!

SCH-I535 ? 2

 

Ok, you do drive much more aggressively than me on average. Some days I don't have the patience and well, my mpg be damned.

 

That's everyday for me.... My 500.00 escort radar detector is worth it.., still a clean record!
But I don't drive stupid either, otherwise I would be dead on my bike.

SCH-I535 ? 2