12 June 2012

Let's Talk Numbers

Slow Paced Rush Hour
This post is by one of Copenhagenize's finest, Rachel.  She's been involved in quite a few of our projects, including the next Copenhagenize Index for bicycle-friendly cities.

By now we all know (or have at least heard) that cycling is beneficial for cities, and the benefits range from improving health to decreasing congestion. For those who aren’t on board yet, some of the findings we developed here at Copenhagenize should help change your mind.

We can talk on and on about the various benefits that come with bikes, but when it comes to municipalities actually implementing policies and infrastructure, the conversation will inevitably turn to numbers. How do the real costs of driving a car compare with the costs of riding a bike? We believe we have developed a comprehensive cost analysis to properly compare these modes of transport.

With Christine Grant spearheading this effort, we were able to come up with a cost analysis that incorporated typical factors such as travel time, vehicle and road maintenance, health, and carbon emissions. However, we also made sure to include several other factors that would represent the real costs of driving and cycling rather than just the face value costs we often encounter that only account for gas prices and carbon emissions. These factors include noise pollution, the impact of oil leaking from vehicles on water quality, parking and a city’s branding/tourism.

Population, modal share, average household income, and the cost of a gallon of gasoline are city-specific values that can easily be changed for each city, but in order to provide a concrete example, we looked at numbers for Christine’s hometown – Seattle, Washington.

Basic Stats:
Population: 563,374
Average Household Income: $45,736
Cost of 1 Gallon of Gasoline: $4.15
Total Trips (all modes) Annually: 5.9 million

Modal Share:
Bicycle: 2%
Pedestrian: 7%
Public Transit: 18%
Car: 73%

For calculating the costs of maintaining and operating a car and a bicycle, we took not only internal but also external costs into consideration.
Internal costs include:
  • Travel time
  • Vehicle/bike usage (gas, tires, maintenance)
  • Health
  • Parking Fees
External costs include:
  • Air, noise and stormwater (i.e. from oil runoff) pollution
  • Road deterioration
  • Parking Infrastructure
  • Branding/tourism
  • Climate change
  • Congestion
Out of these costs, there were two particularly interesting comparisons. The internal time cost for cyclists is $0.33/km and $0.16/km for motorists, which is a $0.17 difference between the two. Based solely on these numbers, it seems like cyclists are paying twice the amount of motorists to get somewhere, but this is where a crucial cost comes in: maintenance and operation. Cyclists pay a meager $0.03/km but motorists are paying $0.71/km (hello, peak oil!). At this point, cyclists are paying $0.36/km and motorists are paying $0.87/km (a $0.51/km difference). The margin, however, gets even wider as we factor in all the external costs, and we conclude that cycling actually results in a profit of $0.46/km ($0.73/mi) whereas cars cost $1.13/km ($1.82/mi). The total cost difference is $1.59/km ($2.55/mi) between cars and bikes!

Now that the financial benefits of cycling over driving are clear, what would happen to a city if there were a modal shift of just 1% of drivers becoming cyclists? In order to have this modal shift, there would need to be approximately 8,300 drivers becoming cyclists to have a 50.5 million km decrease in Vehicle Kilometers Traveled (VKT) and a 32.4 million km increase in Bicycle Kilometers Traveled (BKT) per year.

So by this point, we’ve been crunching a lot of numbers and our brains are running at full speed and as a result, we’ve got some compelling figures to prove the bicycle victorious over the car once again. By shifting 1% of drivers to become cyclists, $57.2 million is saved from reducing the goal VKT and $14.7 million is profited by increasing the goal BKT for a total benefit of $71.9 million.

So there you go. Are you convinced?


Marcus Brito said...

Could you further disclose the methodology you used to arrive at those numbers? I'd love to apply it to my own city (Porto Alegre, Brazil) and see how we fare.

zmau said...

You should also consider cost of medical care for traffic violence victims. As far as I know, state pays for it (at least in my country). And then we can continue with their lost working time, disability pensions, and so on.

Dennis Hindman said...

It's faster and easier to move around by car in a typical American city than it is by bicycle. Relatively cheap gas compared to northern european countries, an abundance of parking spaces in cities such as Los Angeles and decades of roads built to accomodate the automobile.

These are some of the major reasons why the bicycle plays such a minor role in transportation here.

It would be very difficult to make major leaps in bicycling modal share in the U.S. in a short period of time. Trying to convince people that the current 1% bicycling modal share is worth devoting more money to and taking away space from the other 90 percent of road users to accomodate them is not very convincing. You would be arguing that if you put this infrastructure in, then you might get this result. That's a leap of faith that most politicians are not willing to take.

Jake Wegmann said...

Indeed, I was wondering the same thing as Safesler. The annual number of trips equates to only about 10 trips per resident per year, which surely can't be right!

Alexa said...

I really dislike the argument that all bike trips in the USA are longer than all car trips. I live in a small (50,000 residents) city, about 1 km from the center and 3km from my children's school. The time difference between what it takes me to bike vs. drive ANYWHERE in that circle is maybe a minute or two. When I factor in having to FIND parking (we're an old city), and walk from place to place, the difference is even less. Add in the time I'd spend exercising to make up for sitting in my car, and it's a wash. And I bike very slowly.

The other thing that gets me are the arguments about being all sweaty upon arrival. Somehow I manage to dress and ride in such a combination as to rarely arrive stinky. It's not like you're competing to get to work faster than your neighbor. Slow down and enjoy the ride. The more you do it, the easier it will be.

Whatever the true costs, it's unlikely that politicians will find the money to build large amounts of cycling infrastructure in the US any time soon. Often the distances are too great, but the hurdles are so high and the bike industry doesn't hold a candle to the driving industry in terms of political clout. Can you imagine a bike company getting the bailouts GM and Chrysler have gotten over the years?

Anonymous said...

You are missing another big class of environmental costs: The costs of cleaning up all the pollution caused by the oil industry in service to the motoring public.

This includes everything from environmental damage at the oil well sites themselves (spills, leaks, disposal of drilling fluids and co-produced brines), to the costs of cleaning up leaks and spills at refinery sites and tank farms(and the air pollution these sites also generate) to gasoline spills during pipeline, train or truck transport from refineries or tank farms to retail fuel sales locations, to the cost of cleaning up groundwater contamination from leaking underground storage tanks at retail and other storage locations.

Anonymous said...

in response to dennis hindman's comment - here in Boston (admittedly not a typ american city) it's faster to travel 5-6 miles or so(8-10km) by bike than by car in city traffic during rush hour. over a 1/3 of commuters here take public transit (and that share is growing) - but often it's still faster to travel by bike. If cycling is so much faster, why aren't people in a city like Boston cycling more? is it infrastructure? safety? would increased cycling just take away from public transit ridership?

btw - modal split in Boston: 2% bike, 14% pedestrian, 35% public transit, and 45% car.

Rachel Om said...

Thanks everyone for your insightful and interesting responses!

For the methodology, calculating the cost and benefit analysis was done by simply adding the various factors listed above (internal and external). Determining the costs for seemingly ambiguous factors such as travel time is definitely a tricky task. For our analysis, we consulted Kenneth Gwilliam's book The Value of Time in Economic Evaluation of Transport Projects and with that, had to make some assumptions (ie The value for adult personal travel time is 30% of household income per hour. Cars are traveling at 40 km/hr (25 miles/hr). Bicycles are traveling at 15 km/hr (9.3 miles/hr)). The city of Copenhagen's CBA model was also used to generate figures for factors such as Branding/Tourism and the environmental issues.

Our calculations are by no means perfect because there are definitely more factors that we might have missed (think about the endless number of environmental, social, economic and political connections you can make from any of the factors we already included), but we tried our very best to think through these calculations and present the most comprehensive analysis possible.

It's true, realistically, we can't assume that every decrease in car usage would go directly to cycling, but it's necessary to set some sort of fixed rate so that we can generate tangible calculations. Although these calculations could be applied to any city by changing city-specific data (population, modal share etc), if a very in-depth, comprehensive study were to be conducted for a city, it would be necessary for that city's transportation patterns to be analyzed in order to establish an algorithm that distributes car modal share decreases to a city-specific break down of public transportation, cycling and walking.

I hope these clarifications helped and were able to answer your questions!

Cole Hendrigan said...

Rachel, great work. I try to do this same type of work except in counting costs and benefits of high capacity transit services, so I understand the issues of trying to calculate a convincing argument equally applicable ev-er-y-wh-ere... A simplified model cannot account for outliers but rather demonstrates a relationship between factors. If one doesn't agree with an assumption, or if assumptions change, that is fine, but the relationship still stands. What is most important in this type of work is that you, and others like you, can now begin to make the same sort of 'assertions' regarding infrastructure that traditional car-biased traffic engineers have been making for the last ~50 years. You can then use their 'numbers language' as effectively to make the case more compellingly. Hopefully governments will become aware of the enormous impact car-based city fabric costs to citizens, councils and the broader economy and invest in more 'appropriate' hard surfaces.