Mastodawn

Carmen Bianca BAKKER Jul 27, 2023

I'm going to try _a thing_. There are two related phenomena regarding #cars and #PublicTransport that I basically never see discussed. I wrote an article about these two things which includes two very clear definitions. I want to see if I can get some reach to disseminate these two things like a mind virus.

Boost if you like. Or don't. I'm not your boss.

The premise: when you own a #car, it is cheaper to drive the car. But: we want to get people out of their cars, even while they still own cars.

The definitions:

- Sunk cost discount: for as long as you own a car, it is cheaper relative to public transport to use that car for individual journeys, even though you would save money if you got rid of the car and exclusively used public transport.

- Trip cost scaling problem: for each additional passenger taking a journey together, the cost per passenger becomes lower when travelling by car, but higher when travelling by public transport.

The article: https://www.carmenbianca.eu/en/post/2023-07-27-the-sunk-cost-discount-and-the-trip-cost-scaling-problem/

Shamelessly tagging @notjustbikes @TheWarOnCars @ianwalker

#cycling #bancars #urbanism #train #bus #metro #tram #SunkCostDiscount #TripCostScalingProblem

The sunk cost discount and the trip cost scaling problem

Cars are more expensive, but not when you already own one

Carmen Bianca Bakker

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Carmen Bianca BAKKER Jul 30, 2023

A tiny addendum update after receiving a lot of warm feedback on the article :) Thank you.

There are many, many, many reasons why people take the #car over #publictransport. The two phenomena outlined in the article are barely a factor in some cases. I am aware of this, but wanted to hyper-focus the article on one thing only: the cost of public transport for car owners. I did this for a simple selfish reason; I want my family to visit me more often. They don’t much like long car rides, but the alternative journey by #train makes no economic sense for them.

Furthermore, I’m aware of the externalised costs of taking a car, and did mention them in the article, but it bears repeating: the only reason car journeys are so cheap is because we subsidise the hell out of cars and their #infrastructure and off-load all the damages incurred by them (opportunity cost, productivity loss, #health, #environment, #climate) onto society. But everything else remaining the same, I’d still like my family to be able to visit me by train more cheaply than by car.

#bancars

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Carmen Bianca BAKKER Jul 30, 2023

I’ve also learnt the word I would have needed to type into DuckDuckGo to learn about the economics involved: #MarginalCost. It’s jargon related to economies of scale, that when translated to transportation means loosely the following: the increase in total cost [of a mode of transportation] by increasing the [journeys taken] by one. I could rephrase the definitions in terms of marginal cost, but I’m afraid to get it wrong, so I’m not going to.

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Carmen Bianca BAKKER

There are also a few ways around the sunk cost discount (some good, some bad).

- Car rentals: By not owning a car, and only renting one as needed, you get rid of the sunk cost, freeing you up to take the mode of #transportation that makes the most sense for your journey.

- #Bikes: #Bicycles have a near-zero per-journey cost. Hard to beat. #Cycling 🚲

- #ElectricCars #EVs #EV: I really didn’t account for these, but electric cars, too, have an extremely low per-journey cost. In a world where most cars are electric, the sunk cost discount is going to be especially egregious. From this perspective, I think that the sunk cost discount merits a lot more attention than it currently doesn’t have.

#bancars