Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Suburban Ride-Sharing Is Mathematically Unlikely

citylab.com

Post reply on HN
Print view View original

11–20 of 70 posts

Re: Suburban Ride-Sharing Is Mathematically Unlikely

#11

Post by HappyTypist »

This 'paper' relies on some very flawed assumptions and hence have no basis in reality.

Ridesharing services like Uber aim to be cheaper than car ownership, while being as reliable as running water. Many people are finding that once they add up all their vehicle costs (maintenance, depreciation, parking, registration, fuel), uberPOOL or even uberX is cheaper than owning a car. Plus, you get to work or relax on the ride instead of focusing on the road. How much is your time worth?

Assuming that only 10% is willing to pay less for a superior experience is absurd. Once you change it to a more realistic figure of a third to a quarter, the conclusions fall apart.

Re: Suburban Ride-Sharing Is Mathematically Unlikely

#12

Post by VLM »

alistairSH wrote: post #10
VLM wrote: post #4

The article has two insights, which are kinda related in an surprising way. One is tangentially mentioning that car poolers almost always know each other and will not go with random strangers; I thought to myself, yes, I am not young and I cannot remember ever hearing or seeing first hand a "hitchhiker" style car pool although coworkers helping each other out (critically, without a dedicated app/service middleman) is…

Hitchhiker-style carpooling is alive and well in DC. http://www.slug-lines.com/ All the major arteries into DC from Virginia have HOV lanes. At many major interchanges, there are parking lots. If you want a ride that doesn't take 2+ hours, you park at the interchange and hop in a stranger's car.

Yes, but its a context switch. You can't build unicorn for a billion people if the maximum possible market size is actually 10K people, or to be extremely generous, we'll say a couple million absolute tops.

That is an interesting sized market for a lifestyle business or maybe a government sponsored non-profit to target. Startup with VC money? Not really.

Re: Suburban Ride-Sharing Is Mathematically Unlikely

#13

Post by jcfrei »

IshKebab wrote: post #3

This is probably about as accurate as the Drake equation. At the company I work at in the UK, probably 80% of people lift-share. Admittedly that is unusual but still. The article makes several mistakes anyway: * "8 out of 31000" is one source to one destination - so it is very misleading * They don't realise that people might be willing to work different hours in order to find a lift share * 10 percent seems unoptimi…

I was wondering why he would pick Redwood and Palo Alto as an example. To me that doesn't seem like a typical commute in the US. The distance is only 12.5km, you could almost travel by bike. Anyway I think VLM's first comment is a much more intuitive explanation why ride-sharing is not attractive.

Re: Suburban Ride-Sharing Is Mathematically Unlikely

#14

Post by brudgers »

It seems that the conclusion is drawn from specific premises:

+ The measure of a ride sharing app's value is cash on cash returns to Silcon Valley style investors.

+ A ride sharing app's primary market will be in the US.

+ The suburbs served will be affluent, and hence the ride sharing app's user base will tend to have economic flexibility in regards to transportation.

+ The served markets will have poor public transportation infrastructure.

On the one hand these are all reasonable assumptions for the conclusion regarding a ride sharing app's commercial prospects. This is important because ride sharing apps (particularly in a political context like Silicon Valley) are a free lunch: $200,000 spent on software development won't even buy the land for a ten parking space lot in a place where it would be useful.

On the other hand, the numbers in the article suggest that a ride sharing app could readily produce a ten parking space reduction in demand for a city like Palo Alto. And because the marginal costs of adding additional cities to such an application are negligible, reduction in demand for parking spaces across a region like Silicon Valley could be several times that.

In other words even if a ride sharing app is not going to pencil out into a possible unicorn, it still may be good public policy. And perhaps a better alternative to a public policy decision to raise the cash price of parking since it could induce willing social change via better communication infrastructure rather than forcing changes in behavior by pricing out those least able to afford changes in parking policy.

Parking policy is a great area for consultants to consult municipalities. Back in 2002 I was a junior urban planner in St. Pete, the city was "debating" removal of exiting parking meters installed for baseball in 1998. In the department library one day, I saw a study from 1962 that concluded that the parking meters installed in 1957 should be removed. The arguments are always the same: 1. Not enough spaces so install meters, 2. Meters are a hassle for local businesses' customers so take them out.

Re: Suburban Ride-Sharing Is Mathematically Unlikely

#15

Post by HappyTypist »

VLM wrote: post #8

Here's a super depressing mathematical proof of why the services fail in the burbs: First the assumption is a car is necessary for living in general. I am very happy for the 0.1% of the population who live in an urban hugbox where they don't need a car, but this is a general argument for 99% of the population or a unicorn sized middleman app. My garage costs perhaps $50K lifetime, including land, maint, all added tog…

Point to point transport may be necessary for living in general, but a personal car certainly isn't. A more realistic comparison would be selling your car, cancelling your insurance, repurposing your garage, and comparing it with pooled ridesharing.

I'm not sure why you think car pooling has to take a lot of time. Services like uberPOOL guarantee you will only be matched with someone going a very similar route -- otherwise, you get a solo ride (for the pool price). It typically doesn't add more than 2-3 minutes.

Your time cost calculation is also invalid. When you're riding instead of driving, you can use your time for other things. It may be checking up on your email, working on your latest project, or reading hacker news. You can't do that if you drive. Ridesharing actually gives you more hours while saving you money.

There is no question that it's more economical to have one driver for 3 riders, than having everyone driving. Traditional carpooling suck because of the low level of technology, network effect and optimization - but ridesharing achieves all of these and can be superior to driving.

I do not have a car. I never intend on getting a car. I don't even have a driver's license, and I know many people in a similar boat. How do I get around? I Uber + public transport everywhere. My standard of living is far better. I get to do things I want to do (or chat to strangers if I'm bored). I save money. I reduce road congestion and emissions. And I'm not the only one.

Re: Suburban Ride-Sharing Is Mathematically Unlikely

#16

Post by xyzzyz »

facepalm wrote: post #2

Where I live, commuter trains are packed, though (Europe). How can that be? The same logic should apply to commuter trains as to cars?

In Europe, the number of people willing to use public transit is much greater than 10%, for one thing. Another thing is that you don't really need to get matched with someone going the same direction as you: people generally value living close to public transit (which is completely opposite to people living in California, who try to avoid it), and public transit generally gets you where you want to be, possibly with one or rarely two transfers.

Re: Suburban Ride-Sharing Is Mathematically Unlikely

#17

Post by brudgers »

VLM wrote: post #12
alistairSH wrote: post #10

Earlier quoted context omitted.

Hitchhiker-style carpooling is alive and well in DC. http://www.slug-lines.com/ All the major arteries into DC from Virginia have HOV lanes. At many major interchanges, there are parking lots. If you want a ride that doesn't take 2+ hours, you park at the interchange and hop in a stranger's car.

Yes, but its a context switch. You can't build unicorn for a billion people if the maximum possible market size is actually 10K people, or to be extremely generous, we'll say a couple million absolute tops. That is an interesting sized market for a lifestyle business or maybe a government sponsored non-profit to target. Startup with VC money? Not really.

I agree there's a context switch. But the original article makes one as well. It goes from the conclusion that a ride sharing app can't become a unicorn to suggesting a public policy that raises the costs of parking.

So the context of public policy is in the article and I suspect that the conclusion to raise parking prices "in Palo Alto" intends to make all four of its audiences - capital investors, parking consultants, municipal managers, and believers in the new urbanism - happy.

Re: Suburban Ride-Sharing Is Mathematically Unlikely

#18

Post by alistairSH »

VLM wrote: post #12
alistairSH wrote: post #10

Earlier quoted context omitted.

Hitchhiker-style carpooling is alive and well in DC. http://www.slug-lines.com/ All the major arteries into DC from Virginia have HOV lanes. At many major interchanges, there are parking lots. If you want a ride that doesn't take 2+ hours, you park at the interchange and hop in a stranger's car.

Yes, but its a context switch. You can't build unicorn for a billion people if the maximum possible market size is actually 10K people, or to be extremely generous, we'll say a couple million absolute tops. That is an interesting sized market for a lifestyle business or maybe a government sponsored non-profit to target. Startup with VC money? Not really.

Sure. I was simply replying to your point about getting in a stranger's car.

Re: Suburban Ride-Sharing Is Mathematically Unlikely

#19

Post by dannypgh »

VLM wrote: post #8

Here's a super depressing mathematical proof of why the services fail in the burbs: First the assumption is a car is necessary for living in general. I am very happy for the 0.1% of the population who live in an urban hugbox where they don't need a car, but this is a general argument for 99% of the population or a unicorn sized middleman app. My garage costs perhaps $50K lifetime, including land, maint, all added tog…

0.1% really?

I live in Pittsburgh, Pennsylvania. 25% of households here have no car, and we don't have the world's best transit system.

Per http://blogs.wsj.com/economics/2014/01/21/vital-signs-more-h... it's over 9% of households that don't have a car- and of course the average size of a household is above 1, so your fake statistic is two orders of magnitude off from reality.

You're welcome to be hyperbolic, but especially among engineers making up probabilities that have no bearing on reality feels more like intellectual dishonesty than hyperbole.

I think a lot of the HN demographic is completely out of touch with the fact that a lot of people simply can't afford a car.

Re: Suburban Ride-Sharing Is Mathematically Unlikely

#20

Post by rconti »

IshKebab wrote: post #3

This is probably about as accurate as the Drake equation. At the company I work at in the UK, probably 80% of people lift-share. Admittedly that is unusual but still. The article makes several mistakes anyway: * "8 out of 31000" is one source to one destination - so it is very misleading * They don't realise that people might be willing to work different hours in order to find a lift share * 10 percent seems unoptimi…

How is that misleading? A commute typically has one source and one destination. Some folks in Redwood City are going to Belmont. Some folks in Belmont are going to Palo Alto. It seems to me his model scales just fine. Unless you're proposing that the driver drop her passenger at a different location than she is traveling to. But this increases the commute time by a fair bit, which makes ride sharing less attractive. In particular, you start losing any time you gained by being able to use a high-occupancy vehicle lane.

If everyone spontaneously agreed to ride-share, the traffic on the roadways would go down, commute times would go down, vehicle miles would go down, all kinds of great things would happen. But this proposal suffers from a game theory issue.

Post reply on HN