General > General Technical Chat
Confused about PHEV, Hybrids, etc...
bdunham7:
--- Quote from: Someone on August 14, 2022, 08:12:47 am ---However, seems you're just going to keep arguing to the ends of the earth about how your US car centric view is the "majority".... :-//
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Actually, here's what I said on that subject:
--- Quote ---Rideshares and taxis work well in lieu of personally owned vehicles in congested urban areas if other public transportation doesn't work well. Suburban USA, not so much. Rural USA, no way in hell. I'm guessing it isn't so much different in other countries that I've observed, but I'd be happy to defer to those that live there.
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So I'll just speak on what I know well, the US. My 'corner' of the world (California) accounts for ~0.5% of world population and ~3% of the worlds motor vehicles, IIRC. And both electric vehicles and rideshare services in modern form first appeared here in any significant volume. So it isn't a minor player or a small, local anomaly.
--- Quote ---Attached is an example density of the US, the majority (within the US, before considering the 95% of the world population outside those borders) live in dense suburbs or cities not the acre+ block per person you're imagining from the mass media representations. "Exploratory analysis of suburban land cover and population density in the U.S.A". The majority of the world live in cities, the majority of the US live in cities.
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So if I understand correctly, we are discussing the viability of an SDC service supplanting private cars to the point where users would willingly no longer own a car. As I said previously, newly developed areas or places where people already don't own cars would be different as SDC services would just be taking market share from taxis and other public transportation. The city that I live in has a density of about 2k/km2, so right in the middle of that big peak on your graph. LA County is about 1k/km2, but the majority of it is probably about the same as my city because there is a lot of undeveloped area. In my estimation, almost everyone to the left (lower density) of me on that graph and probably a good chunk to the right--say up to 5k/km2--would absolutely not give up their cars for an SDC service, even if they might use the service on occasion. So about 2/3 of the US population or nearly 200 million cars aren't going away. That's based on my observations about how people use their cars, cost and convenience. For some, cost would be the issue and those people will be the ones that manage their per-mile costs to be much lower than is achievable by a for-profit commercial service. For some, like me, it would be convenience and the way I use vehicles. Keep in mind that we've had Uber longer than anyone and I've used enough to evaluate its pros and cons.
The core problem with these ideas, IMO, is that you are simply replacing a car with a different car. My cost example, as low as it was, was my most expensive per-mile car. We have a BEV that we use for the majority of our driving and the incremental cost of keeping it around is trivial. Even when Uber was subsidized by investor cash and by drivers not understanding how much their (required) newer cars were depreciating and wearing, they were much more expensive than just driving our own. And for me and a lot of others, cost isn't the primary factor--as I said, you could triple my costs and it wouldn't affect my decision nor that of any of my neighbors AFAIK.
So to sum it all up: An SDC service as opposed to a privately owned car (which, b/t/w, could also be an SDC if they ever actually produce one) will always end up driving more miles simply because there is always at least some deadheading. Because of that and the nature of a for-profit operation where there is always at least some overhead, staff, etc, the SDC service will always have a higher per-mile cost unless you try to add back in things like the cost of parking at home. Thus your viable cases for an SDC service are where parking is unavailable or prohibitively expensive (on an incremental basis, not paid-in like mine) or the paid-in parking owner can somehow recover value from the unused parking and there are not good public transportation options already and the users don't mind other aspects of shared usage, like not being able to keep their beach chairs in the trunk.
bdunham7:
--- Quote from: tom66 on August 14, 2022, 02:23:49 pm ---I suspect places like the USA in suburbia land is so cheap it may have little impact but in denser areas it would have an impact.
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It's about a million dollars an acre around here, but the plots were laid out long ago so there is little opportunity for change. People have and do convert their garages to other uses, but the driveways remain. Newer high-density developments can be more compact, but I haven't seen any without parking around here yet. Typical new high-density single-family homes are 2 or 3 stories with an 18" side yard and a short driveway in the front yard. You could convert the garages and park in the driveway if permitted (HOAs can be silly), and even if you didn't have a car the concrete driveway is just about as usable as anything else--so losing the cars still doesn't net you anything.
Someone:
--- Quote from: bdunham7 on August 15, 2022, 12:07:34 am ---As I said previously, newly developed areas or places where people already don't own cars would be different as SDC services would just be taking market share from taxis and other public transportation.
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If you can't imagine how a share car (self driving or not) is different to a taxi or mass transit, then you're never going to get it.
--- Quote from: bdunham7 on August 15, 2022, 12:07:34 am ---the SDC service will always have a higher per-mile cost unless you try to add back in things like the cost of parking at home. Thus your viable cases for an SDC service are where parking is unavailable or prohibitively expensive
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We get it, you want to cost parking as zero. That's explicitly what we said is misleading, as parking has a cost. Private cars are parked up and doing nothing more than 95% of the time, storing all those cars while they are doing nothing is a cost to the individual and society. The promise of car sharing is that the number of vehicles required will be reduced, and the fixed operating costs (parking, registration, etc) are divided among many users which should more than offset the additional repositioning movements.
tom66:
--- Quote from: bdunham7 on August 15, 2022, 12:07:34 am ---The core problem with these ideas, IMO, is that you are simply replacing a car with a different car. My cost example, as low as it was, was my most expensive per-mile car. We have a BEV that we use for the majority of our driving and the incremental cost of keeping it around is trivial. Even when Uber was subsidized by investor cash and by drivers not understanding how much their (required) newer cars were depreciating and wearing, they were much more expensive than just driving our own. And for me and a lot of others, cost isn't the primary factor--as I said, you could triple my costs and it wouldn't affect my decision nor that of any of my neighbors AFAIK.
So to sum it all up: An SDC service as opposed to a privately owned car (which, b/t/w, could also be an SDC if they ever actually produce one) will always end up driving more miles simply because there is always at least some deadheading. Because of that and the nature of a for-profit operation where there is always at least some overhead, staff, etc, the SDC service will always have a higher per-mile cost unless you try to add back in things like the cost of parking at home. Thus your viable cases for an SDC service are where parking is unavailable or prohibitively expensive (on an incremental basis, not paid-in like mine) or the paid-in parking owner can somehow recover value from the unused parking and there are not good public transportation options already and the users don't mind other aspects of shared usage, like not being able to keep their beach chairs in the trunk.
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We can't really predict human behaviour here, there's a big attraction to cars as an aspect of class. But I don't see the per-mile cost as being more. A typical private car spends 95% of its time parked up, slowly deprecating. An SDC can use a lot more of that time, say, pretty much all the time between 6am and midnight, with maybe one or two charging stops depending on mileage. Deadheading would assume that the car returns to the same location to pick up passengers, e.g. going between a city and an airport. But why would an SDC not just pick up the next car-passenger pair? If cars are less common anywhere, there will be a journey. It's just taken you to work, now it picks up Betty to go to the shops, and collects Dave from the shops to go back home, and then takes John to the airport... The connectivity is complete with very limited void periods; and if there are any void periods, these can be used to charge, for cleaning, or just idling (but at very little cost, as the driver's not hourly!)
The only reason (imo) Uber is as expensive as it is, is because there are limited numbers of drivers who need to be paid a wage. When you change that to an allocation of SDC vehicles then it becomes feasible to offer the service at a much lower cost.
Think about it this way, if say the average CA car is $40,000 and lasts 15 years and does the average of 12k miles per year, then per mile depreciation alone is 22 cents per mile (that's more than nct's quoted cost on depreciation alone, but this is a new car.) Plus you need parking, insurance, fuel, maintenance, have breakdowns and, if you really want to look at it from an economists lens, there's the opportunity-cost of buying that $40k car over putting that in your pension or going on holiday more often. Even if you don't allocate your driveway's cost, what about the places you go? Even if the parking is free, someone is paying for that, and that *is* reflected in whatever you buy. That could be better allocated if cars didn't need to be stationary for so much of their lives.
OK, so what if you buy a car half-way through its life but because it's a little undesirable it only costs $10k? The maths on depreciation looks better, as you buy at the more linear part of the deprecation curve, but you then have the unknown of prior service history (I've bought a car before that later transpired to have mostly fraudulent history.) You have to spend e.g. that $10k twice as often because the car lasts half as long on average, and you have potentially higher risks of getting a proper lemon (like I did!) Of course, the used car market is funny now, and demand has shifted more into used cars, raising their price. It's still probably cheaper, but harder to work out. Still, about 40% of cars on the road are leased in the UK, suggesting that there's a strong bias towards 4-year and newer cars.
An SDC may, say, with sensors and car computer cost, say, $50k (I figure you save a lot of money by making it not compatible for human drivers), but it could do 500k miles before being scrapped. (I think this is feasible with general maintenance; age is worse than mileage, in general.) Half the cost per mile, but with NONE of the other mentioned costs, just "tap on an app and go". Instead of spending 95% of its time parked up, the SDC is spending only 33% of its time parked up. It's doing perhaps 13x more mileage per year, so it reaches its mileage limit in about 3 years. At which point, it may get a new battery pack, or it might be allocated into different service e.g. shorter routes, or be recycled. Since the parts only need to last, say up to 5 years at a time, it may be possible to optimise them for higher mileage instead of age. Certainly, it's clear that buses can do many years of service with just general maintenance.
sokoloff:
--- Quote from: tom66 on August 15, 2022, 08:22:20 am ---Think about it this way, if say the average CA car is $40,000 and lasts 15 years and does the average of 12k miles per year, then per mile depreciation alone is 22 cents per mile (that's more than nct's quoted cost on depreciation alone, but this is a new car.)
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The average car in the US is 12.2 years old. (I think, but am not sure, that this is the average of registered cars.) Given that CA is one of the better climates for car longevity, I think it's far to estimate that cars last quite a bit longer than 15 years, likely bringing the figure you calculate down to $0.12-15.
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