TerraPass Answers – your help needed

Written by pete


We’re always happy to receive your feedback, comments and questions at TerraPass. But sometimes it’s difficult to be able to answer everything, especially when we may not have the necessary expertise.

So we thought it might be a good idea to pass on some of the questions we get to our blog readers… can you help Pia or Maria? Leave any answers in the comments below. If you have a question of your own, send it to [email protected].

**Should I buy a hybrid?**

> We are looking for a new car and are considering a Toyota Prius (Hybrid). The problem is, that at the moment that car price is definitely the upper limit that we can afford, so we want to make sure that…

> 1. We make an investment that will keep it’s value in the future, as we will probably need to sell the car in seven years.
> 2. There will not be a better solution in the close future. In that case we would maybe buy a used car for now and in a few years get a newer technology car which is hopefully gas independent.

**How much do you save by inflating your tires?**

> Can you give me the formula for determining CO2 emissions for properly inflated tires per year vs. improperly inflated tires, as well as the cost savings?

> If a car’s tire is supposed to be 30 psi and it’s 27 psi, that’s a 10% reduction. How much extra Co2 is being emitted? How much $$ is it costing?

Can you help? Leave any suggestions in the comments below.

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  1. Becky

    I have a Prius and highly recommend it. It is a good car, comfortable and efficient like all Toyotas. It was a good investment 2 years ago when gas was under $3 a gallon. I get around 51 miles per gallon compared to the 26 I got with my Camry. I usually fill my tank every other week versus weekly so I spend about 1/2 as much.
    The difference in what I spend on gas more than makes up for the extra in the car payment.

  2. Drew

    1. Do you currently need to buy a new car? Sounds to be like you do not need a car right now. The benefits of buying a Prius are kind of offset if you are just dumping a vehicle that runs fine. If you do not need a new car do not even worry about buying a Prius. Also cars are never an investment. I highly doubt a Prius is going to hold its value for 7 years. Lastly if you are short on cash and do need a new car just pick up something like a Yaris. Gets very good gas milage and is very economical.
    2. I think you are going to have to do your own homework for your question. Even vehicles of the same model have too many differently variables to say how much is being offset. While these things are minor there are variables such as current gas mileage which varies between how you drive as well as engine condition. There are also minor things such as the different drag between tires though this is typically very minor when it comes to mpg. What you need to do if you really want to know is drive your car with fully inflated tires and then after a fillup drive it with partially deflated and you be the judge. There is no exact formula for this without knowing more details of your vehicle and other conditions. I know there have been multiple topics on this stating that tire pressure does not matter. As an avid bicycle ride though I would like to beg to differ on that point. Anytime your tires are under inflated your going to have more rolling resistance and the car will take a little bit more energy to move. Now this might not be a huge difference depending on how much under but I think the best process is to just keep your tires inflated at the recommended amount. Personally I keep mine 3-4psi over the recommended amount.

  3. Cindy

    I have a Civic hybrid and would recommend it if you are in the market for a new car. It is a good car, reliable and efficient like all Hondas, and I don’t notice any difference in handling/performance versus a regular Civic. Mine is a 2003, and it has held its value to the same extent as other Hondas do. I get around 45 miles per gallon, and I would be the first to admit that I am not a particularly fuel efficient driver, so I would think this is a reasonable estimate of what you can expect. As to upcoming technology, it’s hard to predit what might come out in the near future, but remember that for anything that doesn’t use gas, you will need not only the new technology, but also the supporting infrastructure to be put into place, so I personally don’t believe it’s going to happen in the next few years on a widespread basis.

  4. richard schumacher

    I’m also a very happy Prius owner. People should never buy *anything* at the upper limit of what they can afford. A car is an expense, not an investment. It is usually less expensive overall to keep what you now have or replace it with a good used car with better fuel economy. A precise answer depends on what you drive now, what you might buy, how long you plan to keep it, and the price of fuel. For example if your current car gets 25 MPG overall and gas costs $4 per gallon, it costs you 400/25 = 16 cents per mile for gas. A 50 MPG Prius would cost 400/50 = 8 cents per mile in gas and save you 8 cents per mile. If you drive 10,000 miles per year and your current car is paid for, a $24,000 Prius would save you $800 per year in gas and take about 30 years to start saving you money overall (ignoring differences in maintenance and insurance costs, and interest if you finance).
    Under-inflated tires reduce fuel economy because the tire wall flexes more as it rolls, which wastes rolling energy by turning it into heat. There’s no rule of thumb that covers all tires and cars, but as a single data point, when my Prius’ tires are under-inflated 10% it uses roughly 5% more fuel. If you assume the same and remember that one gallon of gasoline creates 20 pounds of CO2 you can calculate how much of an increase that would mean for your car.

  5. Jeremiah

    In response to the first question, I would maybe wait until Honda either starts selling the Honda “Hindsight” (just kidding, but I miss the style of the original…), which will very much likely be priced to be very competitive (~$18-$19k) with the Prius and offering fuel economy on par with that of the Civic Hybrid. Or you could wait until 2011-2012 when Toyota will have the Plug-in Prius available (hopefully at a price (after tax-rebates at least) similar to that of the current Prius.
    I personally am tempted to buy the Insight when available, however I am also very tempted to wait for the Plug-in Prius.
    With regards to Question #2, it all depends on such factors as total vehicle weight, ambient temperature, wear of the tires, and speed.

  6. Alex Censor

    While a true hybrid-electric such as the Prius or the less-visible-but-equally-good Honda Civic Hybrid are the top of the heap in gas milage, they are not quite as efficient or “green” as the raw mileage figures may suggest.
    Simply put, when it comes time to replace those big expensive batteries part of your gas savings gets offset and it is not clear what the environmental cost of making and recycling those batteries really is.
    In simple economics (just dollars over time) if you compare getting a Prius or Civic hybrid to getting another very gas-efficient conventional car unless either you drive massive amounts of miles, or gas goes up even more to say $6 per gallon, it is very hard to really justify the extra cost of the hybrid.
    You will have to calculate the break-even point but off-the-cuff I’d say that unless you drive 30,000 miles a year or more you’d do better dollarwise getting a regular high efficiency car:
    For much much less than a Prius you can get a Toyota Yaris or a Honda Fit or a ScionD, New.
    They get almost a good mileage as the Prius on the road.
    You can get a Toyota Yaris for about $13,000 to $16,000 tops. A new Prius will run you between $26,000 and $30,000. You can buy a heck of a lot of gas for that $12,000 to $15,000 difference.
    And you’ll find probably much less wait for a Yaris or Fit or even a honda civic than for a Prius.
    And _where_ you drive most matters a great deal: The hybrids milage advantage is most pronounced in city driving — less so on the open road.
    One might say “I’m willing to pay thousands of dollars more for a Prius, even if it doesn’t really pay for itself in my case to be able to be more responsible and more green.”
    But CONSIDER THIS this: Perhaps there is something much more green and carbon saving you could do with that “extra” $12,000 to $15,000 you save by buying a Yaris or Fit instead of a Prius. Maybe you could put some solar elecric panels on your roof? For only $3000 you could put solar hot water collectors on your roof which will reach full payback in as little as three years in some cases.
    Much less sexy and much cheaper — you may save much more carbon emissions by paying someone to double the insulation in your attic… for a tiny fraction of that $12,000 “premium.”
    I haven’t mentioned the tiny Smart Car at $12,000 to $16,000 because their mileage while better than the Yaris and Fit isn’t THAT much better and the waiting list for them is about 1 to 1.5 years (unless you want to pay a ridiculous premium price.)
    Or you could donate money to green political candidates or organizations, or ??????
    Or simply wait until Toyota and other makers officially announce the release of their true plug-in-hybrids (which will REALLY cut back both on net emmissions and on dependence on oil) and promptly put yourself on the waiting list.
    See what I mean?

  7. Dave

    Buying a Hybrid–
    It is tempting to look at this purely from a dollars standpoint. Problem is, can you predict the price of gas in the future? I can’t. What is the dollar value of a sustainable environment in our future? Are you going to be part of the problem or part of the solution? My hybrid gives me peace of mind knowing that a.) my carbon footprint is about half what it would be otherwise and b.) I don’t really need to be so concerned about the price of gas anymore since I rarely need to fill up. That is a great thing these days since I get the sense many others obsess and worry about the price of gas impacting their monthly budget. Since cars are a depreciating asset it is unrealistic to expect any car to “pay for itself” right now. But you can get one that you are happy driving that does not pollute as much as the old car you have now– that is why I’d make the switch to a hybrid even if it looked like a break-even in other respects.
    Note– there are ways to get around with a lower carbon footprint than driving a hybrid. I bike to work most days now, which is uplifting and empowering, as well as a zero carbon form of transportation. If you can do that, by all means it’s the best investment of all! It WILL pay for itself in saved gasoline, parking, insurance and maintenance costs vs. driving a car. Also my biking to work 4.5 miles is just as fast as driving a car would be. amd faster than taking the bus. And I’m not adding to the urban smog. I get to see and interact with my community up close and appreciate the passage of the seasons, weather and even sometimes ride along with others in my area who are picking up the idea.
    Tire Pressure–
    For the tire pressure question, I agree you need to do your own calculations (not complex) based on your particluar car. Everyone’s car and driving style is different. My Honda Insight on a road trip last weekend was getting 65 mpg. Then I aired up the tires fully (whew, they were quite low – 22 psi? if the gas station’s gauge was accurate). Suddenly my average mpg for the whole trip started going up again, so that by the time I got home my average was up to 68+ mpg. That means that after adding the air, I was getting mileage in the low 80s. not bad!
    I tend to keep the air pressure at the high end of the recommended range, since I understand this reduces friction slightly although handling may be diminished slightly.

  8. Jorge

    I did a simple calculation: if a properly inflated tire has a diamter of 16″, then it takes 126,050.7 turns of that tire to travel 100 miles. (this comes from 1 mile=6330″ and the length traveled during one turn is the tires perimeter= Pi*diam). If you underinflate the tires to decrese the tire diameter by 1/4″ (I don’t know what the pressure would be because it depends on the car, the tire, the load, temperature, etc) then it takes 128,051.5 tire turns to travel 100 miles. The difference is equal to 1999.5 turns of the underinflated tires. This, finally is equal to 1.56 miles, that is, a 1.56% increase.
    Not a lot, but considering that underinflated tires don’t only decrease the effective tire diameter but also increase friction (the contact surface gets larger), the effect on gas consumption is worse. Furthermore, underinflated tires wear faster, and so does the motor, oil, etc. So, about 2% or so perhaps increase in efficiency (and CO2 emissions!) would be about right. In terms of money, at $4/gal, that would be an extra $50 per 10,000 miles or about 1 week of free gas if the tires are properly inflated.
    An interesting Canadian web site discusses this issue nicely: http://www.betiresmart.ca/inflation/

  9. Donny

    Contrary to the advice I’ve been reading on this thread, replacing your current car with a hybrid _will_ save on CO2 emissions. The reason is simple, and has been known in scientific circles for a good while: 90% of the energy used by a car over its lifetime comes from driving it; only 10% comes from building it. With a 9 to 1 ratio like that, it makes sense that even a small change in fuel economy will have a great positive impact on overall emissions. It actually makes energy / emissions sense to trade in your old car for a hybrid. However, only you know your finances, so you’ve got to decide whether it makes financial sense.
    Someone also posted that you’d lose the energy and cost savings in replacing the battery, but the battery at least of the Prius is expected to last the lifetime of the car, and cars have been documented beyond 230,000 miles on the original battery pack. In fact, these cars are taxis, which undergo the most horrific driving you can put an engine through (stop and go traffic, lots of short trips, almost no highway driving). And the taxi company discovered that mile for mile, their Prius’s save them 66% over their old taxis.
    Avoid using a car if you can, but if you can’t, buy a hybrid. We have yet to see the end of gas price hikes, IMHO.

  10. Donny

    As for tire inflation, it does matter – I saved 2 mpg by inflating my tires closer to the tiremaker’s max pressure, rather than the manufacturer’s recommendation. That’s about 4% for me. The ride is a bit bumpier, but I can handle that.
    A larger issue is the type of tire you get. I mistakenly put some “performance” tires on my Prius for a few weeks, not having done my homework. Although I could probably take corners in the rain at 30 mph, I lost more than 10% fuel economy (5 mpg at least) immediately. I got them switched out with some “touring” tires that worked a lot better for my style of driving.

  11. Tobin

    For question #1 I recommend you visit http://www.fueleconomy.gov to be able to compare, side-by-side, all the models available now based on cost, size, fuel economy and even climate impact. You could also consider a used Prius. I have seen those on the lots when people trade them in for a newer model. They seem to be holding their value pretty well because they are still so much in demand. I believe we are still quite a few years out from real availability of plug-in hybrids and all-electric vehicles.
    As to question #2 – fuel economy is reduced by 0.3 percent for every psi drop in pressure for all 4 tires. (More tips on improving mileage through proper maintenance is at http://www.fueleconomy.gov/feg/maintain.shtml.) If your car gets 25 mpg with full psi, you would get about 22.5 mpg at 27psi. That comes out to be about $0.40 per gallon and about 8 lbs extra of CO2 per 100 miles driven. You can assume 20 lbs of CO2 for every gallon of gas used.

  12. Alex Censor

    Dave wrote, in part, above —
    “..It is tempting to look at this purely from a dollars standpoint. Problem is, can you predict the price of gas in the future? I can’t. What is the dollar value of a sustainable environment in our future? Are you going to be part of the problem or part of the solution? …”
    I competely agree that it comes down not simply to “will it really save me money out of pocket over time” (seems to me the answer to that is a clear “maybe”) and there is indeed the separate issue of am I willing to put my self and my dollars toward a solution. No one said that being green is going to be free or cheap in every case.
    HOWEVER, my point is this:
    It will cost about $12,000 to $16,000 more to buy a Prius than, say, a Toyota Yaris or a Honda Fit (both very fuel efficient and refined reliable well equipt cars)
    Sure, it is possible that there will be a net reduction in greenhouse gases and other impacts comparing the Prius to the also-gas-efficient Yaris or Fit.
    BUT the question is this:
    ARE THERE OTHER WAYS YOU COULD SPEND THAT $12,000 to $16,000 (the difference in price) that would MORE contribute to solutions than pouring it into the Prius?
    What if you took $3000 of it and put a solar hot water collector on your roof?
    What if you donated it to the Enviromental Defense fund or the League of Conservaton Voters (a group very effective in getting enviromentally dangerous people out of congress)?
    What if you used a small part of it to increase the insulation in your attic from R-16 to R-64?
    What if you used part of it to put in a geothermal heat pump to heat your home?
    What if you used $600 of it to get an electric bicycle and replaced some of your car trips with bike trips.
    What if you used about $3000 of that excess to get a serious comfortable electric scooter with a decent range such as
    and eliminated even more of your car trips?
    What if that cash would allow you to work fewer hours per year? How much would that save in enviromental costs?
    What if $16,000 is enough cash to jump start you into your own home business so you don’t commute to work anymore?
    So, The question isn’t just “am I willing to pay extra to be part of the solution” but also “is putting $12,000 to $16,000 dollars to get a car that gets EPA mileage: 48/45 mpg rather than 33/38mpg (the Honda Fit) really the wisest and most efficient way to be part of that solution?

  13. Tom Harrison

    Second question first: for some factual information on Tire Pressure from the US Government, check out http://www.fueleconomy.gov/feg/maintain.shtml which answers your second question, $$ saved, based on current gas prices. Savings depends on how much tires are under-inflated.
    Each gallon of gas results in 20 lbs of CO2 (see how an 8 pound gallon can do that at FuelEconomy.gov: http://www.fueleconomy.gov/Feg/co2.shtml). You can do the rest of the math 🙂
    Back to the first question: My wife and I each have Priuses (Prii?) and cannot say enough good things about them. They are reliable, get great mileage, have even better emissions than what you would expect from just using less gas, are very practical, and fun to drive. Currently, the Prius, Civic, and Altima are the only hybrids that really do a superb job on mileage (others tend to use the energy for increased acceleration). So I would recommend a Prius or these others if you are buying for the first time, replacing a dead car or trading in your old car (the old one will be resold, so make sure to add that into the calculation).
    It is true that new models will be coming on the market in the next several years. However, it may take a year or two to figure out which ones live up to their hype. Like any rapidly advancing technology, it’s going to get better later (but usually more slowly and not that much better).
    Why not buy a used Prius or Civic? Toyota guarantees the batteries for the first 100,000 miles, and reliability of existing Priuses has proven to be similar to Toyota’s other cars, in other words, great.
    But I do agree with another comment here: if you can’t afford the Prius, don’t buy it. It’s not an investment, it’s just a cost or expense. Maybe we should all think really hard and ask, do we really need that second car? Is a bike, train, bus, carpool, ZipCar or other mode of transit doable? Think of how much money and energy you would save that way!

  14. Chad

    I just want to applaud Alex for pointing something out: It is very possible for something to be a green choice yet not be an effective green choice.
    Buying a hybrid will almost certainly reduce carbon emissions. On the other hand, unless you drive 40k+ miles per year, it is not going to save you money. You will lose quite a bit of money, most likely. A quick rule of thumb (courtesy of Consumer Reports) is that every extra year you can hold on to your old beater car, you save yourself about $3000, because older cars are cheaper to own than new ones. If you drive like a normal person, a Prius is only going to save you $800-$1000 per year, implying that you are going to lose $2000+ per year buying a Prius (of course, you will have a lot nicer ride). How many Terrapasses can you buy with $2000? Enough to offset the difference between a Prius and your beater 50 times over or more.
    While your next car should be an efficient one, swapping out a functional car for a new one is not an effective use of your environmentally-friendly money. Keep driving your beater, buy offsets, and donate just 10% of your savings to good enviromental charities, and you will almost assuredly do more good for the environment AND wind up with $1750 in your pocket. Do this for a few years, and you have just made that Prius or Volt you are going to need when your beater finally dies a heck of a lot more affordable.

  15. Alex Censor

    Oh, Thanks Chad:
    On my list of some alternative ways to spend the “extra” $12,000 to $16,000 the Prius’ green margin will cost you….
    …. I neglected to mention one obvious alternative that Chad brings up. Buying Terrapasses.
    Yes, I know that doesn’t give me the good feeling of having an aura to be “making a statement” with what I drive (“look at me — I’m not supporting big oil”), but is it more important to look green or to be very effective with with being part of the solution with my limited resources?
    My four cents (used to be “two cents” but devaluation of our currency by a blundering admistration requires more cents be used.)

  16. Chris R

    Just with regards to the Prius question, I personally own one and I love it, but my wife is buying a Civic Hybrid. The Civic is cheaper up front for only slightly less fuel economy. I got the Prius over the Civic because
    a) I drive 600km (~365 mi) each week, so the .5 l/100km (~5 mpg) difference adds up to 3L (.8 gal) saved ($ and Carbon) weekly. In a year, that’s ~800 lbs (362 kg) of CO2. That matters enough for me to spend the extra $ on the Prius, and
    b) I can install a battery pack from Hymotion to allow extended gas-less driving (running on only battery power) and improved fuel economy even at high speeds. It costs ~$11k US and should save ~150 gallons (or 3000lbs CO2). Up here, I pay CAN$1.06 / L, or ~US$3.30 /gal this week, so that’s ~US$500 per year. This means, since the batteries are expected to last 7-10 years (about as long as the stock batteries), I won’t get my money back.
    Used Priuses (?) are very hard to find up here, so while I expect they depreciate about as fast as other cars, people seem to hold onto them, which should drive the price up (if supply/demand economics work)…
    Overall, I agree with what most posters say, that you should never buy the most expensive car you can, you should buy the most fuel-efficient car you can reasonably afford, and balance its emissions with ~TerraPass.

  17. Zac Helmberger

    For a new car?
    I do not recommend a hybrid! Too many parts that can fail. I have a bare-bones 1995 Suzuki Swift (it doesn’t even have a radio)! At 7,000 feet in Taos, New Mexico, I routinely get 50 MPG! And on three occasions, I got over 60 MPG on a tank of gas by staying under 50MPH on highways (you can get away with it in rural locations)!!! At Sea level, I can barely get 40 MPG. If I milk it by driving 45 to 50 MPH tops (where possible and safe), anticipate stops, etc., I can get to the mid-40s at sea level.
    It is the luckiest car I have ever had! No major repairs and it is at 130,000 miles. Pop open the hood and it is simplicity itself. You can actually see the engine, the distributor, the spark plugs, the alternator, etc. Very repairable!!!
    All this excitement about the hybrid is BS as far as I’m concerned. The only problem is you cannot buy a car like mine NEW anymore. The minute George W Bush got into office (2001), the production of fuel efficient cars (Suzuki Swift, Geo Metro, i.e. anything that got over 39MPG HWY) stopped. At 7,000 feet, I can get better MPG with my Swift than my wife can get with her 2004 Prius! And it cost me less than $10,000 new!!! The Prius fuel economy is about the same at sea level.
    My recommendation is to buy a well maintained Swift or Geo Metro. Use the money you saved to buy spare parts such as CV joints, clutch, brake pads, engine rebuild kit, etc. Insurance is a LOT cheaper, too.
    Here’s the other thing: Repair and maintenance costs!!! My wife has a 2004 Prius and it is very expensive to repair and maintain. The inverter blew out. We had to have it towed from 13 miles NW of Taos all the way to the dealer in Santa Fe, NM. The inverter cost $4,000!!! But we got it all done FOR FREE! because Nicole got the extended coverage at the time of purchase. Saved our *ss, big time!!!
    Just keep it as close to the limit as you can. It does help a little. See below for actual data:

  18. Chris R

    Excellent points, Zac.
    However, not everyone has the patience, opportunity, or skill to drive like you do. Some people can even get up to 75 MPG on non-hybrid, fuel-efficient, cars by driving hypercarefully.
    The difference is for us normal folk, who speed on the highway ’cause we’re late for/from work, who drive on a busy 1-lane highway, etc. In my Prius, I consistently get >50 MPG with no effort.
    The problem with Hybrids and repairs is that, at least for Toyotas and Hondas, they’re extremely reliable. BUT, if something in the hybrid system goes awry, the cost is quite high. So, it’s gambling. I’m likely to not need major repairs any time soon, but if I do, I’ll pay for it…
    –Chris R

  19. Alex Censor

    A footnote, since I and others have mentioned full electrics and plug-in-hybrids (which run full electric most of the time) as greener alternatives:
    Here’s something that makes them a bit, maybe significantly, less green, which until recently, I was ignorant (and which I’m sure most people are unaware:
    In an article in the magazine “Scientific American – Earth 3.0” (www.SciAmEarthe.com) titled “Catch-22: Water vs. Energy,” they point out that (a) water is a critical resource that we are hitting shortages of and (b) all significant current sources of energy production us significant amounts of water.
    They have a chart, page 40, (relevant to this discussion) as follows. If indicates how many gallons of water us used associated with the energy production to move cars driven by different energy sources to drive 100 miles:
    Ethanol vehicle: 130 to 6000 gallons of water.
    Hydrogen fuel cell vehicle: 42 gallons of water.
    Plug-in hybrid
    (presumably applies
    to a full electric):
    24 gallons of water
    Gasoline vehicle: 7 – 14 gallons of water.
    Interesting. Doesn’t rule our electrics or or plugin hybrids to me, but something to consider.

  20. nick

    My wife and I got a used Prius. It rocks. We get 45 MPG’s on average, and it would be more if drove more, but we walk to work so we only drive every other day or so. If you’re going to get a new car anyway, definitely get a Hybrid. Even if something better is coming in the next year, I would suggest buying a new or used hybrid, if you can find it, and then trading it in for the better something in a year or 2. I was able to get my Prius because someone traded theirs in for a newer one. Even though a car is never an investment, there is no better car investment right now than a Hybrid; They can and are reselling like hotcakes.

  21. Holly

    I have read they are coming out with a new Prius that will get 90 MPG within the next year or two. I would definitely try to wait if you can. Also I’m sure other new cars will be on the market by then as well so you should have more options. Until then, you can always ride your bike or take a bus.

  22. Ken

    If you are like me, you are cheap.
    Yet conscious of the environment.
    But too cheap to spend $30,000 on a hybrid car.
    And, still hoping for cheaper transportation costs.
    (And, possibly, cynical abut people who claim that automobiles of any kind will “save the planet”. But I digress..)
    So my cheap but environmentally-conscious friends, I offer my own low-tech but quite sensible rule. I call it my $3000 car rule:
    When buying a replacement car, it must be a low milege car; it must also cost a maximum of $3000.
    The current one is a 1993 Ford Tempo. It gets about 30 mpg, and cost me only $1800 to buy used with 50,000 miles on the odometer.
    It now has 110,000 miles and has been dirt cheap for repairs.
    Try it. There are plenty of cheap, low mileage cars for sale IF you are not too choosey about what you buy.
    Even if it is not a thrifty hybrid, you are reusing someone’s used car, saving the energy needed to make you a new car, and avoiding ongoing car payments.
    If the cheap car gets somewhat reasonable mileage, that is of course a bonus, but not a requirement unless you drive a lot.
    This system beats a hybrid for cost/mile easly.
    If you want to go further to “save the planet” (which seems unlikely anyway unless a plague suddenly wipes us all out) just shut your cheap car off at stoplights and restart to go; you have now created your own alternate system, and will offer even better overall mileage.
    You will have plenty of spare money to replace the starter every few years, or to buy a solar panel for your house. (I spend my savings on the theatre. Opera.)