Hybrid vs. Standard on Almost Purely Highway Driving

[Spoom]

Hi all,

We are considering a (much) more efficient used car as a replacement to one of ours.  Both myself and my wife commute (yes, I know, move closer, but our jobs are in different directions) an average of 487.5 miles per week, and 95% of that is on interstate highways.

My wife's father suggested that since we're not doing city driving, the electric motor wouldn't get much of a chance to run, and so a hybrid would be a waste of money.  I am very skeptical of this (especially given that he drives SUVs and minivans), so I figured I would throw the question to the forum.

Which is better for almost entirely highway driving, a fuel efficient standard gas car or a hybrid?

[naloj]

There's lots of cars that get 40-50mpg highway and the top of that range are hybrids.

There are other optimizations for fuel efficiency aside from the battery like no accessory belt on the Prius to pull power off, lighter weight materials, more efficient parts, and better aerodynamic profiles.

Your FIL is sort of right.  There are hybrid cars that don't provide any highway mpg benefit.  For instance, Toyota makes hybrid versions of the Avalon/Camry and those only have better fuel efficiency for city driving.

[Vangogh]

If you look at a prius vs a corrolla, you would have to drive 250-350,000km just to break even on the difference in base model price (this is new, since buying used toyota's in northern bc doesn't provide depreciation savings) when highway driving is assumed. Since this takes about 10 years and will likely be at the end of the vehicle's life I would just stick with gas models.

My preference is the hatchback mazda 3 because for a little less reliability it is a lot more fun to drive and more versatile than the corrolla. YMMV.

[AJ]

Hybrids aren't *bad* on the highway, they just don't have the same discrepancy between city and highway mileage like regular cars do. As an example, our 2001 Prius is rated at 42 city and 41 highway - basically the same.

My wife's father suggested that since we're not doing city driving, the electric motor wouldn't get much of a chance to run, and so a hybrid would be a waste of money.

You are right to be skeptical of this. The electric motor is still used on the highway. Also the gas engine is used in city driving - the two hand off. It sounds like your FIL might not have a lot of knowledge of hybrid cars.

Which all doesn't mean that you *should* buy a hybrid. The biggest factor is going to be how many miles you expect to drive, not so much whether the miles are city or highway. At >2000 miles a month it is very possibly worth it to get a hybrid. You'd have to run the numbers for how much it would save you in gas vs. how much extra it will cost to buy.

[RunHappy]

It depends on what your goal is.  If you're looking for alternative energy sources, then I would look at  hybrid or electric (if possible), but if you're looking at overall fuel economy, there are a lot of cars out there where the mpg beats most hybrid cars on the market.  I like the Mitsubishi mirage, these cars get solid upper 30s lower 40s for mpg.  I had been wanting to get one, but they get snatched up quick because people want just a small (3 cylinder) car.

I ended up getting a Ford Focus and it gets in the mid-30s (I'm a highway commuter).

[Prepube]

I exclusively drive my prius on the highway and get 51 mpg.  Bought the car for under 10k. It goes back and forth between battery and gas.  They do better in the city because the brake helps to charge the battery.

[Spoom]

Which all doesn't mean that you *should* buy a hybrid. The biggest factor is going to be how many miles you expect to drive, not so much whether the miles are city or highway. At >2000 miles a month it is very possibly worth it to get a hybrid. You'd have to run the numbers for how much it would save you in gas vs. how much extra it will cost to buy.

I have been running the numbers (I have a spreadsheet where I plot the yearly gas savings over our current cars and the time in years to recoup the purchase price in gas savings, as well as the mileage at break even as a sanity check) and so far the Prius has been mostly winning even with just the highway MPG used.  I've also found that for a 2007 Prius, the difference in purchase price between standard gas and hybrid almost vanishes.

Electric would seem to be a bad idea for the purchase price (much higher, yes?), the range (remember, we're doing long distance highway commuting), and the fact that it's a new technology (which I usually stay away from until the bugs are worked out).  LMK if you disagree, I'm open to suggestions.

What are your thoughts on the endgame mileage of Priuses?  (Prii?)  I've seen a bunch of reports that as long as you're OK with replacing the battery every 250K or so miles, they last a while.

[skunkfunk]

My wife's 6-speed Cruze eco averages 50 mpg interstate, the same as my buddies Prius hybrid of roughly the same year.

Can't speak on normal toyota vs hybrid, though. I do know his Prius has been a pain in the ass for maintenance.

[acroy]

Hybrids only have an advantage in start/stop, slowdown/speed up situations

Steady-state cruise, both conventional & hybrids just become a gasoline-powered car. The hybrid gets no chance to use regenerative braking, shut off the engine at lights, etc. It's also carrying around a big battery & electric motor which is not being used.

If your commute really is 95% highway, I suggest sticking with a good efficient conventional car. the price difference of the hybrid will probably never be made up in fuel savings.

[Spoom]

If your commute really is 95% highway, I suggest sticking with a good efficient conventional car. the price difference of the hybrid will probably never be made up in fuel savings.

See, this confuses me as I have been plotting highway fuel economy of the Prius vs. other used cars in the same year range, and the Prius tends to win.  Are the highway MPG numbers lying?

[acroy]

the Prius is an extremely slippery 1.5l car and will post great numbers at steady-state highway speed even if the hybrid system never kicks in.

also I *think* the EPA fuel economy tests cycle has fairly aggressive speed up/slow down sequence to it; which allows the hybrid to recover some of the energy which would otherwise be wasted.

not saying the Prius is a bad choice at all; just that the hybrids do extremely well in city use but the efficiency gap will narrow quite a bit in highway use

[gimp]

Hybrids only have an advantage in start/stop, slowdown/speed up situations

Steady-state cruise, both conventional & hybrids just become a gasoline-powered car. The hybrid gets no chance to use regenerative braking, shut off the engine at lights, etc. It's also carrying around a big battery & electric motor which is not being used.

If your commute really is 95% highway, I suggest sticking with a good efficient conventional car. the price difference of the hybrid will probably never be made up in fuel savings.

This is a simplistic answer. There are many hybrids, which use different methods to go from theoretical power -> wheels spinning.

Here's a more full answer.

The good: Electric motors tend to use continuous transmissions instead of a set number of gears (so an infinite possible gear ratios). In addition, a gasoline engine can be used for recharging the batteries - and it runs at its peak efficiency, as opposed to a standard gasoline engine running at a requested speed. This means part of the system is more efficient than before.

The bad: There's a decrease, too. Sure, running an engine at peak efficiency is great, but now you lose power converting its mechanical energy to electrical, in storing the electrical charge, in transmission of the electricity, and finally, the continuous transmissions are not as efficient as simple gearing.

And as you've mentioned, regenerative braking allows the collection of part of the energy previously spent. Conventional braking does not.

Furthermore, where power comes from to the wheels depends on the hybrid. Some are electric-only, using gasoline to charge. Some use the gasoline engine to deliver power to the wheels. I think most of the latter type, at a certain speed, will only be powered by gasoline regardless of electric charge remaining; however, that speed differs - some will kick in at lower speeds, some are capable of higher speeds from the electric motor. Furthermore, there's a lot more than speed that matters - the requested torque as well as speed matters. You might be going up a steep hill at 40 and need gasoline but be fine on electric at 60. It depends!

With all that said, it's hardly a surprise that the prius is fairly efficient on the highway. It's got a tiny little anemic engine. You can do a lot when you don't request a lot of power from a small engine. How acceptable this is depends on your driving style. If you drive a prius at 55 mph in the right lane, you will get far better mileage than if you go 80 in the left. This is of course true for gasoline as well, but the difference is that many prius owners specifically want high mileage and others specifically don't want to be associated with the former group. The car is polarizing, politicized, and this makes getting good information harder!

Whether a hybrid of conventional is more efficient greatly depends on all of those factors; there are some things more efficient, some less, and the combination of all that is complex. I think at best you need to compare two cars. Don't compare two entire topologies encompassing hundreds of design decisions (variables).

[Spoom]

With all that said, it's hardly a surprise that the prius is fairly efficient on the highway. It's got a tiny little anemic engine. You can do a lot when you don't request a lot of power from a small engine. How acceptable this is depends on your driving style. If you drive a prius at 55 mph in the right lane, you will get far better mileage than if you go 80 in the left. This is of course true for gasoline as well, but the difference is that many prius owners specifically want high mileage and others specifically don't want to be associated with the former group. The car is polarizing, politicized, and this makes getting good information harder!

Interesting.  I'm typically driving on Cleveland interstates where I top out at around 70 MPH; on road trips I might get to 80 depending on where I go.  At those higher speeds, would a plain gas engine overtake a Prius-style hybrid in fuel efficiency?   Edit: I wonder if there's a source for fuel efficiency numbers at a given speed; that would let me get a much more accurate picture of how efficient cars will be with my usage.

I'm not particularly attached to one car or the other and I'm definitely looking at everything reasonable in our price range.

This could all be moot since I currently drive a 2003 Impala (inherited, I didn't choose this one).  I may hate the Prius when I test drive it!  Everything's just on paper right now.

[DarinC]

There's a fair bit of misinformation in this thread, but in the aggregate the ideas are right...ish.

Lets run some numbers. KBB says a private party 05 Prius with ~100k miles will run ~$7100 and an 05 Corolla LE (comparable trim) will run ~$5800.

On the unadjusted highway test a 05 Prius gets an unadjusted ~64mpg on the highway test, and something like an 05 Corolla gets 52mpg. The math is pretty easy.

(Miles/52)*$3.5 - (Miles/64)*$3.5 = $1300. Solving for miles gives me ~103k miles. A long time, but break even is possible.

Now... Here's a gotcha. The unadjusted EPA highway test is pretty slow. Something like ~50+mph average speed. This only applies if you can set the cruise control to ~53mph (or whatever) all the time.

IRL (Higher speeds, AC use, etc..), the EPA estimates the Prius will get 45mpg and the Corolla 35mpg. This changes things a bit and brings the break even down to ~60k miles.

So even if you pull out of your driveway onto onto a four lane interstate, the used Prius will still cost less than the used Corolla after ~60k-100k miles. Any city driving you do will reduce this. Plus it's a bigger/more comfortable (IMO) car, etc... I don't think any similarly sized normal gas car (stock) will do better than a Prius at 80mph, not because of engine efficiency, but because a Prius has a lower CdA.

With that said, if you get a 1984 VW Rabbit diesel for $1000 at 43mpg, or a 92 Civic VX at 49mpg at $3000, then it'll take several hundred thousand miles to never to make up the ~$6000 difference. But... If you're going for a small car, then a first gen Honda Insight is hard to beat on the highway. The payback would be longer at ~150k+ ($5k Insight versus $3k VX all highway).

[Prepube]

Very interesting DarinC.  Thank you for running those numbers for those of us who don't think that way without assistance.  Don't forget to add in there somewhere that the Prius engine requires less maintenance and they recommend oil changes only every 5k.  Not sure how that impacts cost in your formulas or if it would be significant over the short term.  Using your numbers, though, I should not have bought the prius, but I really like it, so I am happy with the choice.  I live in the mountains west of Denver, and I commute 30.5 miles to Denver and 30.5 miles home in my Prius three or four times per week.  The first 30.5 of the day is all downhill.  I get between 85 and 99.9 mpg, and weirdly, sometimes I hope for a traffic jam on the highway so that I can get better mileage (the electrical system is more active at slower, stop and go speeds).  On the way home, I have a bit of a lead foot, and I pretty much floor it the whole way (70-80 mph up this big hill is pretty good for an "anemic" engine).  I usually get between 35 and 45 on the way home.  Since purchasing the car I have put about 4500 miles on it and have only done my downhill to work and uphill home circuit (I literally go nowhere else but home and work on those days).  My current overall mpg for those 4500 miles is 50.5 mpg--all highway.  On the way to work I really try to conserve, do a pump and glide type of hypermiling (or try to).  On the way home, I don't give a shit about the gas, I just want to be home.  I am not looking forward to this coming winter, as it'll be my first with this car and the first time since I learned to drive that I have something other than an SUV or equivalent.  Prius's are supposedly less efficient in the winter (the cold makes the battery less efficient) and they are supposedly horrible in the snow.  We'll see.

[alsoknownasDean]

Surely the hybrid will be more economical than an equivalent standard car of similar size, due to the better aerodynamics and smaller engine.

However, it totally depends on how many miles you do per year in it (is that 487miles each per week?), and particularly, the difference in purchase price between the two cars. If the Prius is a fair bit more expensive to buy, then the sums may work out in favour of the regular car.

It's probably also worth doing comparisons at different fuel prices too. Compare the TCO of each at $3.50 a gallon, $4.00, $4.50, $5.00, etc. Fuel ain't getting cheaper :)

[okashira]

Surely the hybrid will be more economical than an equivalent standard car of similar size, due to the better aerodynamics and smaller engine.

However, it totally depends on how many miles you do per year in it (is that 487miles each per week?), and particularly, the difference in purchase price between the two cars. If the Prius is a fair bit more expensive to buy, then the sums may work out in favour of the regular car.

It's probably also worth doing comparisons at different fuel prices too. Compare the TCO of each at $3.50 a gallon, $4.00, $4.50, $5.00, etc. Fuel ain't getting cheaper :)

It is here. :-( Like $2.90/gal. Ridiculous.

Back OT, it's silly to compare "hybrid to regular." it's irrelevant if the car is hybrid or not. All that matters are the numbers. That is why we have standardized testing. If the prius is rated at 50 hwy, and another car 39, then there you have it. Run your numbers. Your FIL thinks he is being clever by pointing out an irrelevant thing about no regen on the hwy, etc. but all that matters are the numbers you will actually get.

The prius is good on the freeway because it has a small engine, it's aerodynamic, and it's a modified cycle engine which has fewer pumping losses then most gassers.
diesel owners will of course point out you can get near prius mileage in them on the freeway. they are "good." on the freeway, but most don't realize that diesel has 15% more energy per unit volume then gas, and it's more expensive to match.
the fact that the prius will beat most diesels on the freeway is actually impressive. ofc, the prius will wipe the floor with them in the city.

Too bad they are so damn ugly and I can't stand how they drive.

[Spoom]

Thanks for the information all.  Believe me, I'm running the numbers for all potential purchases; I just wanted to make sure that I'm counting all the potential numbers.  I haven't looked much at efficient diesels yet, mostly as not every gas station here has a diesel pump.  (Most do, I just don't want to be stuck on a road trip.)  Might be worth some consideration.

In any case, it'll be a while since we'll be paying in cash, so we need to save.

[rmendpara]

Hi all,

We are considering a (much) more efficient used car as a replacement to one of ours.  Both myself and my wife commute (yes, I know, move closer, but our jobs are in different directions) an average of 487.5 miles per week, and 95% of that is on interstate highways.

My wife's father suggested that since we're not doing city driving, the electric motor wouldn't get much of a chance to run, and so a hybrid would be a waste of money.  I am very skeptical of this (especially given that he drives SUVs and minivans), so I figured I would throw the question to the forum.

Which is better for almost entirely highway driving, a fuel efficient standard gas car or a hybrid?

Depends on what car(s) you are considering. A Prius hybrid vs a 6 cylinder Accord will be a huge difference. A more apt comparison will be a Civic (regular) vs Civic hybrid. Using the 2015 EPA figures as a proxy, the hybrid vs regular gets 47/41 mpg highway. For one person (either you or spouse) at ~25k miles per year, the annual gas expense estimate:

- hybrid 25k miles @ 47 mpg = 532 gal x $3.5 = $1,862
- regular 25k miles @ 41 mpg = 610 gal x $3.5 = $2,134
Gas advantage is a few hundred dollars per year, even at a very high mileage level. Difference will increase with higher gas prices or higher mileage, and of course what mpg you are using to calculate.

Comparing a hybrid Civic/Prius/Camry vs a gas guzzler isn't really a meaningful comparison.

Take your annual savings, and consider any changes in cost of maintenance over a 5 yr period (can search for this many places online) and also consider the difference in purchase price.

Between a Toyota Camry, Ford Impala, Chevy Cruze, Honda Civic, you can get anywhere from mid 30s to low 40s highway mpg (non-hybrid versions), and the comparable hybrid versions are usually 10-15% better on the highway.

You are somewhat correct though, that the savings in city driving from a hybrid are much greater than the savings on highway mileage for comparable cars. Just be sure you are comparing apples to apples. It's no secret that a Prius will save more gas than a full gas Camry... the latter is a bigger car.

[Spoom]

Take your annual savings, and consider any changes in cost of maintenance over a 5 yr period (can search for this many places online) and also consider the difference in purchase price.

Thanks!  I'm comparing small cars to small cars, definitely.

Where might one look for estimated annual maintenance costs on used cars?  I wanted to include this in my spreadsheet but couldn't find reliable numbers.

[gimp]

With all that said, it's hardly a surprise that the prius is fairly efficient on the highway. It's got a tiny little anemic engine. You can do a lot when you don't request a lot of power from a small engine. How acceptable this is depends on your driving style. If you drive a prius at 55 mph in the right lane, you will get far better mileage than if you go 80 in the left. This is of course true for gasoline as well, but the difference is that many prius owners specifically want high mileage and others specifically don't want to be associated with the former group. The car is polarizing, politicized, and this makes getting good information harder!

Interesting.  I'm typically driving on Cleveland interstates where I top out at around 70 MPH; on road trips I might get to 80 depending on where I go.  At those higher speeds, would a plain gas engine overtake a Prius-style hybrid in fuel efficiency?   Edit: I wonder if there's a source for fuel efficiency numbers at a given speed; that would let me get a much more accurate picture of how efficient cars will be with my usage.

I'm not particularly attached to one car or the other and I'm definitely looking at everything reasonable in our price range.

This could all be moot since I currently drive a 2003 Impala (inherited, I didn't choose this one).  I may hate the Prius when I test drive it!  Everything's just on paper right now.

That data definitely exists, for example, this company - https://www.automatic.com/ - sells a doodad that you plug into an ODB2 port and it tracks your mileage and speed (among other things) and gives you a nice graph of your mpg vs speed.

But where's the data?

Here's bullshit - http://www.mpgforspeed.com/ - they don't care what car you drive, just your rated mpg and speed. That is on its face utter bullshit; cars that are more aerodynamic lose less at high speeds. It is blatantly obvious it's not this simple.

But how about automatic's blog? http://blog.automatic.com/cost-speeding-save-little-time-spend-lot-money/ this includes "the" prius, but again, there are different models. Good start, but I want raw data!

The company should have a treasure trove of data, for every conceivable model and multiple samples of each model, assuming they're doing okay and selling enough product. (By the way, it's not exactly a "mustachian" purchase at $80, but it's a fun toy. And you could turn it into an investment by using it to find out how to drive more efficiently. They're a startup, with cool people working there.) However they don't seem to publish this information anywhere!

TLDR data exists, I can't find it, sorry.

Also, their math is not entirely honest - they compare minutes saved per hour versus cost of gas per month. Different units. Compare time saved per month of driving or costs of gas per hour. With that said, it is indeed true that for most drives, driving aggressively will save you about one minute and cost you a dollar or two of gas (not to mention the damage you're doing to your brakes, the wear on your engine, the hits to your suspension when you miss the pothole or speed bump), so chill out and don't hurry too much. But when it comes to long distance travel, that extra time adds up really quickly - I tend to go +7 in a 65 and over a day's drive that's over a hundred miles more that I can go. Worth it to me.

70-80 mph up this big hill is pretty good for an "anemic" engine

It is pretty good for that anemic engine. Heck, even flooring it, you get better mileage than I do! With that said, I've been there, and my car on cruise control at 80 needs 2300 RPM instead of the usual 2100 to make it up the biggest mountains the interstates go through. So no need to put sarcastiquotes around "anemic," it is very anemic, and there's nothing wrong with that as long as you stay out of the left lane when you're not passing, which is the only time I take issue with anemic engines. Though I must wonder at the wear you put on the car at 4500 rpm, or however fast the engine has to spin to maintain speed. How long do those engines generally last for? (My car will fall apart long before my engine is even a quarter through its life, which is a bit sad about the rest of the car. GM, why couldn't you do better?)