One limitation I see to the marginal cost model is the lack of information about how many of the part-time drivers got a more expensive car because they expecte

One limitation I see to the marginal cost model is the lack of information about how many of the part-time drivers got a more expensive car because they expected the extra income from driving to pay for itself. For example, Uber requires a 4-door car that can carry 4 passengers. Someone may waver between buying a 2-door and more expensive 4-door model, and justify buying the latter to work for Uber part-time. Similarly, it assumes one-person = one-car but there are one-car families. If one of the families decides to become a two-car family with the new vehicle used 50% for Uber, with the Uber work helping to pay for the car, then the marginal cost model also becomes more like the pro-rata model. Without driver survey information, it's hard to say how this affects the marginal cost model is. Uber also says the vehicle "cannot have any cosmetic damage, missing pieces, commercial branding or taxi paint jobs", so while plenty of people are willing to drive their own beat-up car, they need extra repair work to drive for Uber. This additional cost cannot be described as a marginal cost. Again, I don't know how big an effect this might be, only observe I couldn't find where the authors mention this point. I'm also a bit put off by this sentence: "The highest possible cost would be a driver renting a car ($290.66) and getting private personal insurance ($19.25) for $309.91 per week." The $19.25/week is based on: "We have also included additional personal insurance. Such insurance costs vary widely, but in downtown Seattle an average seems to be $77 per month or $19.25 a week, which is considerably cheaper than buying insurance through the rental car company." That number seems to be from 2021, at https://web.archive.org/web/20210613171346/https://quotewizard.com/auto-insurance/seattle-washington https://web.archive.org/web/20210613171346/https://quotewiza... which says: > In Seattle, insurance rates vary based on which neighborhood you live in. The Seattle neighborhood with the most expensive insurance rates is Columbia City, where average rates cost $90 per month. Compare that to Seattle’s cheapest neighborhood, downtown, where average rates are only $77 per month. Thing is, at the top of the page it says "On average, your neighbors pay $129 a month". This may be because "It's not a great idea to buy only legal minimum coverage. While it costs less, minimum coverage becomes more expensive if you file a claim." Thus, the sentence is wrong, as that's choosing the lowest possible private personal insurance, rather than the average for the city. Which means the $309.91/month does not reflect "the highest possible cost" because it's choosing the lowest possible location cost for the lowest possible insurance - and most Uber drivers don't live in downtown Seattle, I assume. Do they also all opt for the minimum insurance? I don't know, but surely that number is relevant. Do people who opt to drive part-time for Uber keep their existing insurance coverage, or do they get higher insurance coverage? I don't know, and I didn't see the report consider this non-marginal cost.