Monday, January 23, 2012

Highway Congestion

The last major participant we will cover in the Meet Rideshare series is, again, a somewhat, er, ethereal participant. It is the highway system itself, which is scarcely able to breathe at rush hour times, poor fellow, because of how clogged its “arteries”(highways) are. What kind of impact will Rideshare realistically have on congestion on the highways? The answer is, potentially, massive.

Congestion, like pollution, operates on a synergistic basis. Congestion breeds more congestion. This is because congestion forces everyone to slow down. It is amazing how fast a 65 mph highway can turn into a 5 mph in the city of Los Angeles. And the really amazing thing is just how few cars it takes to make it happen.

Highways have a capacity limit, like most networks do. They are built to hold and move a certain number of vehicles, just like cable systems are built to hold a certain number of channels or cell phones are built to move a certain number of bits per second. However, congestion on the highways differs from congestion in cable or cellular systems in one important respect: excludability.

What this means is that when a cable system doesn’t have room to add another channel, it can refuse to do so. The cable operator is coordinating the system, and makes sure that the cable system isn’t asked to carry more channels than it can handle. If a cable system tries to cram five channels into four slots, the picture will become all pixelated and distorted, and customers will not have four or five channels to enjoy. They will have zero. Congestion slows down everyone in the system, not just the newcomer there’s no room for.

Cellular networks, if asked to transmit more data at one time than they have, have a different control mechanism. They simply slow everyone’s transmission speed to the level the system will bear. But even though each individual’s transmission may move somewhat more slowly, the system itself is still working at maximum capacity. A system meant to transmit 1 Mbps for 100 people may instead transmit .5 Mbps for 20 people for example. But A total of 10 Mbps is always moving through the pipes.

Highways are different. A highway which can move 10000 cars at 60 mph cannot move 12000 cars at 50 mph. This is because each additional car on the roads forces every car on the road to move more slowly. What’s more, unlike with cable or cell systems, there is no controlling authority which can stop people from entering the highway once it’s capacity limit has been reached. So as the slower highway fails to get people to their destination, and off the highway, as quickly as before, more people are continuing to pile onto the highway, creating still more congestion which clogs the roads still further, causing the speed of the highway to be reduced again, causing more congestion, and so on. A highway which has even a little congestion on it therefore, or goes even slightly over capacity, quickly enters a death spiral, a negative feedback loop which destroys the utility of the highway for everyone.

Rideshare, however, makes this synergistic snowball effect run the other direction. Taking some cars off the road reduces congestion directly, of course, but it also has additional “knock-on” effects. Fewer cars and less congestion on the highways means that the cars that remain can move at something closer to the speed limit, covering more distance in less time and thus getting them off the highway faster. Getting them off the highway faster means that the remaining cars can move still faster, and get off the highway still faster, thus allowing the remaining cars to move faster, etc.

So you see, Rideshare doesn’t need to get that many people out of their own cars and into someone else’s to achieve a drastic reduction in highway congestion. Indeed, Rideshare’s ability to create clearer and faster highways for everyone in Los Angeles, including those who never use our service, far outweighs even our other positive social benefits. We can make a significant contribution to environmental protection and a somewhat smaller one to climate change, but Rideshare may just have the ability to all but eliminate highway congestion on its own, if we can get enough people onto our service.

Tuesday, January 10, 2012

The Environment

Having examined the three parties to the commercial transaction, I thought we’d take a little time to talk about a few more “interested parties” in corporate commuting, even though they perhaps are a little more, er, abstract. With that in mind, the next “participant” in the Meet Rideshare series is the environment.
Gasoline emits any number of pollutants, which can broadly be broken down into two categories. Local Pollutants are pollutants which linger in the immediate (i.e. same city) area in which they are emitted. The levels of these pollutants in a given city is therefore highly correlated to how much of them is emitted by that city. And so, therefore, actions to reduce emissions of these pollutants benefits primarily the city which has reduced them. Local pollutants include Volatile Organic Compounds, formaldehyde, nitrous oxides, hydrocarbons, carbon monoxide, and particulate matter, and produce such things as smog and soot. They contribute to lung and heart disease as well as just general blight on the horizon.
Global pollutants spread out beyond the immediate area in which they are emitted. The best known global pollutant is probably carbon dioxide, which pools in the upper atmosphere of the planet. Carbon emissions anywhere on the planet are therefore a reflection of carbon emissions throughout the planet, and so are somewhat harder to take action against, since reducing one’s own emissions of carbon does no good if everyone else does not simultaneously reduce theirs. Other Global pollutants include methane, sulfur dioxide, and mercury, which all tend to pool at either the nationwide or regional level.

For the reasons explained, Rideshare’s primary benefit to the environment will be the reduction of Local Pollutants. While Rideshare will also reduce emissions of Global Pollutants, such reductions are not large enough to alter the global balance of these pollutants, since in terms of global emissions one city’s rush hour transportation emissions are a drop in the bucket. A city’s rush hour transportation emissions do however constitute a substantial portion of the city’s own Local Pollutants, and so Rideshare’s ability to reduce such emissions will provide noticeable benefits to the citizens of Los Angeles; even the ones who never use our service.

Putting numbers on these benefits is a little harder. In the U.S., a total of 238 billion vehicle miles were traveled in December 2009. Los Angeles contains about 3% of the U.S. population, so our local vehicle miles traveled would probably equal about 8.1 billion VMT per month, assuming Los Angeles is somewhere close to the average U.S. number. Los Angeles corporate commuters represent, according to our prior calculations, about  4 billion VMT per month(20 miles per trip x 5 million commuters x 2 trips per day x 20 days per commuter per month). So corporate commuting represents close to half of L.A. vehicle miles travelled. We can maybe quibble over these numbers a little bit, but they’re almost certainly not grossly off the mark. According to the E.P.A., automotive emissions account for about half of nitrous oxide emissions and hydrocarbon emissions, and a staggering 95% of carbon monoxide emissions. So if half of L.A.’s corporate commuters join Rideshare, at a one to one Driver to Passenger ratio, total vehicle miles traveled will be reduced by an eighth. This means that CO emissions will be reduced by 12%, and NOx and HC emissions by about 6%.

While that may not sound like much, it is important to remember that environmental pollutants operate on a synergistic basis. That is, each additional pound of pollution does far more damage than the one before it. Reducing pollution by 6-12% reduces the damaging health effects of pollution by a far greater proportion. In fact, the EPA has set a goal of reducing the emissions in the Los Angeles area by half(this is what is required to earn the EPA’s designation of Los Angeles as an “attainment area”), since that is all that is required to eliminate the detrimental effects of the pollutants. Remove half the pollutants, and the other half become harmless. So while Rideshare will not do the whole job, it can make a big dent.

Tuesday, January 3, 2012

The Passenger

The Passenger is the one paying in the Rideshare business model, so the savings to him must be enough to make the payment worthwhile. In order to calculate his payment, we need one piece of information we did not need for the Driver: the total distance traveled from home to work. This didn’t matter in the Driver’s case as he needed to travel that distance anyway. Only the marginal distance added by detouring to pick up the passenger matters to the driver. But since the Passenger’s payment to the Driver will reflect the total distance traveled, we need to know how far they go.

The average corporate commute in the city of Los Angeles is about 20 miles. We know this from both the personal experience of Rideshare management and the results and research of other carpooling companies. We will use this average for now.

Although the mileage price will be determined in a free market transaction between the driver and passenger,  we can make an educated inference about the price. Since the IRS budgets mileage at $0.50 per mile, that is the number we will use for now. (I mean, if it’s good enough for the government…..)
At $0.50 per mile round trip x 20 miles per trip, the Passenger’s payment is $10 per day. Less than a cab fare, but a substantial expenditure nonetheless. Do the benefits to the Passenger justify this expense?

First, let’s calculate his direct savings. The Passenger saves on the gas to drive 40 miles per day, which given time spent stuck in traffic is even more than the mileage of his car would suggest. According to the Consumer Energy Center, an idling car consumes about half a mile of gas per minute. Assuming passenger drives a fuel-efficient vehicle that gets 30 miles per gallon, and also assuming that Passenger spends equal amounts of time moving and idling, idling on a 60 mph highway(average of 55 mph and 65 mph) for half the time on a 20 mile commute means adding the equivalent of 10 miles to the trip in gas costs alone. At $3.90 per gallon, which is the cost at my local L.A. gas station as of November 20th 2011, this means the gas costs of a round trip are equal to $7.80 per day for the Passenger. These are costs he has saved by paying someone else to drive him.

This is less than $10 though. Does that mean that the Passenger won’t use Rideshare? Hardly. Add on the costs of parking, for starters, which in L.A. will be $7-10 if you’re lucky and up to $20 if you’re not. In parking and gas costs alone, you are well above the cost of using Rideshare’s service. We won’t even go into the benefits of reducing wear and use on the Passenger’s car and the more enjoyable and productive  time he spends not having to sit behind the wheel, but instead sleeping, chatting with friends, getting an early start on work, etc.
Next, the Rideshare company itself.