Costs of bike commuting

In 2005, I looked at the economies of bike commuting. It elicited a lot of good questions . Generally, I made a lot of simplifying assumptions, avoiding counting anything that would require a double-blind scientific study. For example, one of the biggest, immeasurable arguments is “improvement to health and exercise.” An additional cost, also immeasurable, is “additional food consumed to offset increased metabolic intake.” My final conclusion was for the commuting I did then, there was a small, quantifiable monetary benefit over driving.

As we’re in the midst of the Bike to Work Commuter Challenge, I wanted to revisit the question with the numbers I collected from last year.

A spreadsheet is available with the specific details, and can also be used to calculate your own return.

For the car expenses, I assumed a “base” of driving to work five days a week, the low-end of the fuel economy band (all that stopping and going), and an average gas price of $2.80/gallon. Assuming I drove 100% of the time, the cost of commuting by car comes to $1,351. The biggest direct expense was fuel ($805). I also included license tags and the delta in insurance savings versus not driving my car “to and from work more than 20% of the time.”

The largest indirect expense ($423) was ongoing car maintenance, which I calculated based on a flat rate of $0.0735 per mile. It’s pretty close to the actual costs spread out over time, assuming I only use the dealer for stuff I can’t handle. (Otherwise, this number would be waaaay low.)

Because I have not achieved the Kent Peterson level of bikeficiency, and I am keeping the car (for now), I did not factor in any kind of vehicle depreciation. I still drive once a week, mostly to replenish food (I eat breakfast and lunch at work), clothes (beats hauling stuff both ways) and extracurricular errands (pick up person M at location S at time T on day D) or work-related meetings, or if we have twelve inches of snow. This effectively reduces the amount I can “save” by not commuting.

1,351 – (1,351 * 1 day driving / 5 day workweek) = $1,080 potential savings.

I calculated my bike maintenance expenses (parts, tools, disposables) came to ~$800 last year. Except for the wheel – which was included in its price – I did all of the labor myself. (Go, me!) As with the car, there is a lot of recreational usage. Thus, I prorated the expenses:

(3,000 commute miles / 4,333 miles total) * $804 = $557 additional expenses

Using Tricky Math, I compute my 2006 tangible savings of:

$1,080 – $557 = $523 Actual savings

Gas at the local 76 is now $3.44/gallon — a bargain for those from Norway or the UK — and expected to rise for the peak summer travel season, traditionally starting after Memorial Day. Out of morbid curiosity, if the 76 station adopts the Norwegian pricing model of $7.80/gallon, the cost savings for bike commuting would pay for a new bike each year.

Intangible Advantages:

• Fun. Combined aerobic workout and commute is a positive way to channel stress.
• Adds to my perceived eccentricities. (As in: “if it’s crappy out, Jim’s-a-ridin'”)
• Reduction in carbon footprint.

Intangible Disadvantages:

• Drivers on cell phones while making turns.
• Morning scowl from coworker.
• “Helmet Hair”.
• Hopelessly behind listening to books-on-tape
• Wasp nests on the car

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One of the interesting comments in the original post came from Reid, who mentioned he has been tracking his expenses since his bike purchase in 2004. In the second tab of the worksheet, I tabulated the maintenance costs for my Bike Friday. The cost-per-mile came to $0.40. For comparison, the IRS allowed deduction for business use of a vehicle is $0.485/mile.

Nearly half of the maintenance was to address deficiencies in the original bike specification. For example, the regular commute — and especially the long, steep downhill in crappy weather — was not good to the small wheels. I went through a pair of them before retrofitting the frame with disc brakes (and new wheels). I’ve also learned how to do most of the maintenance myself. Getting greasy and working on the bike is cheap therapy, sometimes. The obvious next thing to learn is how to build and true wheels.

I went through several disposables — tires, chains and brake pads — and noticed replacements were more frequent during the winter than the summer. For example, on the Comet Primo kevlar tires, I’d see about 1200-1400 miles on a new, rear tire during the winter, its replacement prompted by having too many large-ish cuts in the bottom, exposing the bead. Not surprisingly, I’d get more flats during the three winter months than the rest of the year combined. Next winter I may experiment with bigger, beefier tires on the Friday.

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* Estimated average. +From August 2006 through April 2007, I put about 3,150 miles on my car versus 2,000 on the bike.