Commuting by bike, versus other modes: comparing costs

This discussion began for me as a posting to the iBob email list in October of 2005. Costs have gone up a bit in certain areas, the most obvious area being gasoline which is at least $0.35 more today than when I wrote that posting. What follows below is a revision of that posting where I hope to have cleaned up the presentation. It is best used as a framework for calculating your own costs, and is not meant to imply what your costs would be. For me there are three main options for travel to my current job and back: by car, by bike, and by public transportation. I've used all three at one time or another, but the breakdown is probably 97% by bike, 2% by public transporation and 1% by car. Below, I'll try and lay out the costs for each in turn and then compare those costs.

Before I get into the details of each commute mode, I want to lay out the numbers. I'll mostly be presenting the costs in monthly terms and I wanted to show how I defined a 'month'. In a given year there are 365 days, excluding leap year. I don't work weekends so that removes 104 days of the year. Of the 261 days remaining, my employer observes 10 company holidays. From the 251 remaining days, I also subtract 20 vacation days, leaving 231 days. I get my share of colds and flu so it's fair to remove 6 more days where I don't commute to work. 225 days divided by 12 is 18.75. It is neater to deal with whole days for this discussion, so I'll round up to 19 days a month for travel to work. If I worked a .75 day, I'd still travel the whole way back and forth.

In addition to the number of days I travel, I have to lay out the distance I'd travel too. My ride to work by bicycle is a 35 mile round trip. I've chosen the route I take based on finding the best roads to bicycle that also link me with public transporation. The round trip by car is 25 miles. I could ride very nearly the same route on bike as I drive, but the car route involves a tunnel that is unplesant, noisy, dirty, and noisy. It's also noisy. The boarding points when taking public transportation are fixed so the distance traveled is less important when the destination is the same. So, it isn't fair to project the costs of driving based on the greater number of miles I travel by bicycle, and the result is that I'm working with a daily round trip of 25 miles, times 19 days for a montly total of 475 miles.

Commuting by car: costs

Cost of the car

We have a family car, a 1990 Volvo 740 GL Wagon, with 225,000 miles on it. The current Kelley Blue Book value is ~$2450. I doubt that the car would be worth more than $1000 when it is 20 years old and has ~260,000 miles on it. Given that, I'd spread the 'lost' $1450 cost of the car over four years to make a monthly cost of $30.21. I'm going to round that down to $30 a month. Regardless of the amount of use, if used at all, a car has to be registered. The cost for our car is $70 a year for registration, or $5.83 a month. I'm going to round that up to $6 a month. Insurance companies sometimes give breaks if you drive your car less than 10,000 miles a year. Our insurance costs are about $500 a 6 month term, so that is $83.33. I'll round that down to $83. Running total so far of $119 a month.

Maintenance of the car:

Here is where the costs of a used car begin to catch back up to those of a new car. If my current car is a guide, then there is usually about $1200 in repair costs per year. Remember this is a 16 year old car used as an example. $1200/12 is $100 a month. There are lots of other maintenence incidentals, for example tires. Last time I bought tires for this car the bill came to over $500. Tires might last 5 years at best, so $100 a year, and $8.33 a month. Oil changes four times a year, if done by me would cost around $15 an oil change, or $5 a month. The maintenance total is $113 a month.

Making that car go:

Using today's gas prices isn't fair for the past year, but show of hands, who expects gas prices will go down overall in the next year? Our one family car gets 20 mpg city/highway mixed which is the type of driving I would be doing to and from work. 475 divided by 20 is 23.75 gallons. 23.75 gallons at $3.30 a gallon is $78.38. I'll round that down to $78 dollars.

Costs that I don't include that you might have to:

If you wanted to do the same tally of costs for a car, also consider if you pay for parking at some point as a result of driving to work, and factor in any tolls you might pay (in the Bay Area, bridge tolls of $3 per day are common). I don't pay for parking and I don't have bridge tolls to pay so I haven't included that in my costs. I also am not including costs such as paying for collisions and the like. Those are a fact of life, but so random that it's hard to accurately portray them here.

Summary of car costs:

Cost of ownership: $119
Maintenance: $113
Gas: $78
Total: $310

Commuting by bicycle: costs

There are costs for owning and using a bicycle, just as there are for owning and using a car. The costs for riding a bike have to be listed as well, just to be fair. It stands to reason that for me there is no zero cost way to commute. The costs however are quite a bit less, and paid far less frequently as those for owning and operating a car. Below, I'll first express them in annual terms, and then break that down into monthly figures.

Ownership of the bike:

My commute route is pretty flat as things go in the East Bay so I use a single speed bike. Far less components to wear out or be ruined by riding in the rain or over rough terrain. At various times I've used a bike frame that I've found in the trash and built that up into my commuter. My commute bike is also the recipient of many parts downgraded from my recreational bikes. It's pretty difficult to express an initial cost for the bicycle except in a ballpark way. I'd be surprised if I paid more than $500 on average for any bike I've used as a commuter, and more likely the cost was closer to $100. I think that $400 is a fair amount for the cost of a bike that I would find reliable enough to last four years, as in the example time frame for the car. I might be able to sell the bike for $100 at the end of the four years, so $300 in cost over four years would work out to $75 a year, or $6.25 a month. Let's just call it $7 a month for ownership.

Maintenence of the bike:

On the year, I will have 34 x 220, or 7480 miles, using the route I actually travel. I've gotten as much as 5,000 miles out of a rear tire, but the more realistic standard is about 3,000 miles a year. I'll assume 3 tires a year because the front tire doesn't wear as much and can last the full year and things happen with a rear tire so a spare is a good idea. The tires I use are usually $20, but I always buy a bunch during a sale, and sometimes I 'retire' a tire from one of my recreational riding bikes and put it into use on my commute bike. Someone claimed on this list that a chain will last 1500 miles. I get far more mileage out of chain than that, so say two chains, for $15 each. Tubes run $4.50 each and I get a lot of flats so six tubes a year: $27.00. Running tally is $60 (tires) plus $30 (chains) plus $27 (tubes): $117 a year. Granted other things will wear out, like brake pads. I run mine for a long time so they last a year. I get the cheapest Koolstop Continentals so rounding up I bet those cost $20 a year. $137 yearly. These don't wear out that fast but say $20 for freewheel cog (single speed) and $30 for a chain ring. I don't wear these out in a year, but I need something for the tally. $187 a year, or $15.58 a month, rounded up to $16.

Clothing costs for riding

I suit up in cycling clothes. I paid $60 for a pair of shoes and I've used them for 4 years so far. Let's say I use two pair of shorts a year, and I get them for $40 each. I use rain gear still that I purchased close to eight years ago. Given that I'll just go with the above which are those things replaced annually. $140 in clothing annually, or $11.67 a month, rounded up to $12.

Summary of bicycle costs:

Cost of ownership: $7
Maintenance: $16
Clothing: $12
Total: $35

Commuting by public transportation: costs

To use public transportation, the most obvious option is for me to walk a mile to BART, then walk a mile from BART to the Oakland Alameda Ferry, then a mile from the ferry landing to work. I could also use my bike for those walking links to save time and would mostly likely do the latter. If I walked or rode to BART, then to the Ferry then to work and reversed that at home, the daily cost for me is:
Ferry, round trip $3, BART round trip $3.70 a day. $6.70 X 19 is $127.30.
Monthy figures:
Riding: $35
Public Transportation: $127
Driving a car: $310*
(*purchased just to commute, and including maintenance costs, insurance, tags, etc)

I save about $275 a month cycling to work over buying a 2nd car. I save about $92 a month cycling over using public transportation. To show that with more impact, I save about $3300 a year by cycling instead of buying a 2nd car.

These costs are as exact as I can make them based on plowing through receipts, checking web sites, etc. I recognize these costs are not exhaustive, but I think they are a fair and reasonable approximation, and cover the largest ticket items, and express the low end of the equation. If you have specifics for costs of buying a new car to begin travel to work and back, send me details and I'll work that in as a hypothetical.

One thing that may be obvious, but can't be even closely approximated in cost terms is the difference in time spent in either of these modes. That discussion borders on the philosophical. However, it is still a worthwhile one for me to at least state my case. It takes me about an hour and 15 minutes each way by bicycle, about the same using public transportation, and it takes me about 25 minutes driving into work in the morning and 40 minutes to drive home. Here is the philosophical part. I get so tense, in a relative way, by negotiating the gridlock on the maze near the Bay Bridge and again near University Avenue, that I'd much rather spend the extra time riding. A human being needs exercise and I feel like I have saved the time of going to a gym or fitting all this exercise into my home life by riding to and from work. Besides, I really don't want to end up behaving like this.

In short, the real savings in bike commuting is to either not get, or get rid of a car. If you have a 2nd car that you leave at home, well, you are still paying for ownership, insurance, taxes and most of the maintenance.

The answer for me is pretty clear. Cost wise, it's far better for me to ride.

Comments welcome, no doubt I've forgotten something in my caluculations. If you have comments to make, corrections to point out or things to add, please send me mail at my rob dot hawks gmail dot com address.