Do you know how much your driving trips cost? - Mothering Forums
Frugality & Finances > Do you know how much your driving trips cost?
laohaire's Avatar laohaire 09:36 AM 05-03-2011

I just thought I'd share how I calculated the cost (in gasoline, not wear and tear or anything like that) of common errands we run.


I looked up the average city MPG for our car (city since we rarely travel by highway). Of course it is possible to calculate your actual MPG by tracking your fillups and mileage, but I was content to just grab an average. I found a range and I used the low end (22mpg) because we live in a hilly region.


To calculate the cost per mile, I took the average gas price these days - well, I just used $4/gallon even. 4 divided by 22 is about 18 cents a mile.


Then I used Google maps to estimate the distance to a bunch of common trips - the grocery store, the park, the library, the YMCA, etc. I multiplied them all by 2 (for a round trip) and then by .18. So now I know one grocery store costs 33 cents a trip, and the other one in town $1.45 a trip. The park is 36 cents. The library 18 cents. And so on.


As you can guess, one of the grocery stores (unfortunately, the more expensive of the two) is walkable, as is the library. The park is sort of walkable except it involves a MAJOR hill (mountain, even).


Knowing the cost of the trip makes us more aware of our gasoline usage. Even the little stuff adds up. If we drive to the park every day, that's over 10 bucks a month right there. The grocery store that is further away from us saves us more than the $1.12 extra it costs to drive it, but only if we plan well and shop only weekly or less. If we're running there for just a gallon of milk, it's a huge waste - and now we know that if we really need just one thing, it's better to walk to the closer, but more expensive, grocery (it's more expensive but we're paying less than $1.12 premium on a gallon of milk).


Just thought I'd throw this out there in case it helps anyone else conceptualize their gas usage, and motivate them to plan trips better and walk/cycle more if possible.

mnnice's Avatar mnnice 09:54 AM 05-03-2011

I do this too.  I think my difference between my choices are more dramatic because of our specific situation living in a town of less than 1500.


Nearly everything in my little town is walkable and DH and I usually walk to work.  And I in six months of living here I haven't driven to the local grocery store yet.


On longer (cross country type) trips it motivates me/us to use our more fuel effiecent car.  This is helpful because the other car is more comfortable.


I figure almost $4 for grocery trip to the nearest grocery store I actually like and $9 to either of the two "bigger" cities nearby.  The tacking on $9 to the cost of a nice meal plus the time needed to drive there usually squashes the impulse to eat out.  I buy things like birthday gifts for my kids' friends, nephews, etc online usually from Amazon (I have Prime) because I really don't want to spend $9 on gas to buy a $10-$20 gift.

lilyka's Avatar lilyka 12:08 PM 05-03-2011

You might want to track your car as well.  The web sight for my car says about 22 miles per gallon in town.  I get 20 on a good summer day.  about 18 in the winter.  (harsh winters, lots of idling, lots of spinning wheels on ice, going out of my way to avoid hills LOL ) I am also a really really bad driver as far as gas saving driving habits go.  And this is from a car that is practically brand new.  Less than 10,000 and well maintained.  (hmmm, if I could only learn to maintain my speed, and not ride the clutch....)  I should find out how much my trips cost....Well lets see...$4 for a tank of gas and I drive almost exactly 2 miles to work.  4 round trip.  Thats also where I shop and get gas and bank (handy). Church is half way.  20 miles per gallon.   Well that makes it about $.20 per mile right?  $.80 to the grocery store where I work and $.40 back and forth to church.  Not terrible.

sunnysandiegan's Avatar sunnysandiegan 02:54 PM 05-04-2011

Between carpooling and walking, I haven't driven anywhere in over a week. I've gone plenty of places! winky.gif


One of our cars averages 50.3 MPG and the other averages 29.6 MPG (real data we've tracked in a spreadsheet since Feb 2006), so whoever is driving the furthest that day takes the Prius (50+MPG) and the Camry is available for the other person. No his car and her car. Both cars have appropriate child restraints and always have. When I worked, DH did daycare drop-off and pick-up more than I did. Our Prius is our family car, but when relatives or friends come to town we can fit five people in the Camry comfortably whereas the Prius fits four comfortably and five if 2-3 are slender. The Prius holds more "stuff" due to the hatchback design and the 60/40 backseat folding down flat, but the Camry can hold quite a bit in its large trunk. It has the 60/40 backseat, too, but the opening between the trunk and car makes it far less flexible and useful. We generally keep both cars fairly empty for better gas mileage.


lilyka's Avatar lilyka 11:19 AM 05-06-2011

Wow, that is great gas mileage!!  Is that all in city driving or does it include interstate/highway driving?  If it is all in city do you do anything to improve your mileage?    (obviously the prius gets good mileage for its own reasons ;)  I mean mostly your normal car.)

sunnysandiegan's Avatar sunnysandiegan 12:28 PM 05-06-2011

It is a combination of city and highway driving. I know you are mostly impressed by the Camry's MPG, but I have to relate things to the Prius because it has the tools to figure out what makes things better/worse. The biggest thing going for us MPG-wise is the climate here. The Prius shows us the MPG continuously and it does much better in the warm months than in the cool months. The 50.3 is an average over the life of the car, but it is common to get ~55 all summer-long. Which, of course, means we get in the high 40s during our cool "winters".


The biggest negative factor for us is hills. If you have ever been to San Diego, you know it is a series of mesas and canyons. Most flat areas, even on city streets, have speed limits too high to only use the electric motor on the Prius. One would think anytime you go up a hill and lose MPGs, you'd gain them on the downhill. It *never* works that way. The net effect is lower MPGs no matter what driving skills we have employed thus far.


Aside from those conditions that are largely beyond one's control (climate and terrain), the things we do are common and can be done in any vehicle...


~ Start and stop the vehicle with grace.

~ Use the gas and brakes as little as possible (while maintaining safety, of course). Get up to speed fairly quickly, but STEADILY, and then maintain it with the lightest pressure possible on the gas pedal and/or pulsing the gas pedal. DH "pulses" the gas (easy technique to learn, but challenging to describe in writing), which is good for MPGs and driving solo, but drives passengers crazy. I usually have passengers, so I employ the lightest pressure possible method instead.

~ Group errands and walk between stores. We have one shopping center that has a massive parking lot between Ikea, Lowes and Costco with a public library and an entire strip mall of very small stores along with a handful of restaurants. I park in the middle and walk to several places, dropping things off as needed in the car (inside of Costco is always last). Driving short, choppy distances are the WORST for gas mileage!!! We *can* get only 25-30 MPG in the Prius. It is not a given to get excellent gas mileage.

~ When feasible, plan the route to avoid hills. Better yet, plan to go down the steepest, l o n g e s t  hill and return the shortest and/or gentlest hill. Shorter hills of any steepness have a smaller impact on general. I live in the hills and have LOTS of experience with hill driving! LOL

~ Stop signs are actually worse than stoplights, at least in the Prius. I'm not sure how that translates to an idling engine, though. (The Prius' engine cuts off when you are stopped. Waiting in the Costco line for gas doesn't cost me a dime in the Prius, but does in the Camry.)

~ Maintain your vehicle. Tire rotations, alignments, and proper inflation PSI are particularly important.


I'm out of computer time now. I hope this helps!


Just wanted to add that since getting the Prius, and both of us driving it, our Camry has also gotten better gas mileage. That instant feedback on the Prius computer screen is an excellent teaching device that carries over if one is willing to adapt their driving techniques... winky.gif

littlest birds's Avatar littlest birds 05:50 PM 05-06-2011

I just calculated that my cargo bike saves us around $20/month just in gas.  I can ride with my 8yo riding in back and have huge bags for hauling--today I even strapped on an extra crate behind dd so I could carry home our milk that leaks if it tips. She was totally comfortable and was reading a book while we rode down the street.  We live in a very small town and my longest round trip is nearly 5 miles, which I do twice a week, and make several shorter trips.  We also walk a fair bit.  Our kids all have their own bikes too and use them for real transport.  We have gradually added lights for night visibility as well.


It would take a long time for the bike to pay for itself in just gas but there are several other factors as well.  Our older vehicles are fully paid for years ago and were fortunate bargains and I would hate to have to face replacing them.  Since dh already made the switch to a bike (he drove the gas guzzler full-size truck 2 mile round trip to work every day, plus home and back at lunch before that) I think we have basically arranged for our cars to last at least twice as long.  The truck likely even more than the van.  We have cut our total driving in half even including winter time when we mostly drive.  The truck gets used about twice a month at this time of year.  The van still gets used a few times per week but still I am happy with the difference.  We used to be running around several times per day with different kids in different activities, and we are not even involved in very much.  I am trying to mainly reserve the van when we do shopping in a nearby city


For me a regular bike wouldn't have been very useful, as I am often carrying packages to the post office for our business, we do large shopping trips, I sometimes need to carry musical instruments, etc.  Also super handy for yard sales if you like that kind of thing.  I held out and got the Yuba Mundo, which is one of several kinds of cargo bikes.  I've only had it a month but am definitely happy so far and feeling really really good for the exercise.

lilyka's Avatar lilyka 05:57 PM 05-07-2011

Thanks!  And that is a very cool feature of the Prius!

yeahwhat's Avatar yeahwhat 07:37 AM 05-08-2011

I know exactly how much our car cost per km last year.  Dh is self employed and has to keep track of distance travelled and all car expenses, so it's simple to calculate the cost per km.  It is fairly depressing and does encourage me to walk dd2 to school (2.5km round trip) rather than driving her or walk to the grocery store to get milk rather than driving.  Around here, it's much easier to cut back driving in summer than winter though.