Parking at airports seems a terrible waste -- expensive parking and your car sits doing nothing. I first started thinking about the various Car Share companies (City CarShare, ZipCar, FlexCar -- effectively membership based hourly car rentals which include gas/insurance and need no human staff) and why one can't use them from the airport. Of course, airports are full of rental car companies, which is a competitive problem, and parking space there is at a premium.

Right now the CarShare services tend to require round-trip rentals, but for airports the right idea would be one-way rentals -- one member drives the car to the airport, and ideally very shortly another member drives the car out of the airport. In an ideal situation, coordinated by cell phone, the 2nd member is waiting at the curb, and you would just hand off the car once it confirms their membership for you. (Members use a code or carry a key fob.) Since you would know in advance before you entered the airport whether somebody is ready, you would know whether to go to short term parking or the curb -- or a planned long-term parking lot with a bit more advance notice so you allocate the extra time for that.

Of course the 2nd member might not want to go to the location you got the car from, which creates the one-way rental problem that carshares seem to need to avoid. Perhaps better balancing algorithms could work, or at worst case, the car might have to wait until somebody from your local depot wants to go there. That's wasteful, though. However, I think this could be made to work as long as the member base is big enough that some member is going in and out of the airport.

I started thinking about something grander though, namely being willing to rent your own private car out to bonded members of a true car sharing service. This is tougher to do but easier to make efficient. The hard part is bonding reliability on the part of all concerned.

Read on for more thinking on it...

It does get hard to be a privacy advocate when it's easy to think of interesting apps that make use of tracking infrastructure. Here's one.

How often have you wanted to talk to somebody in a car next to you on the road? Consider a system where people could register their licence plate(s) with their cell phone account. Then, if they had done this, you could call a special number on your own cell phone, and enter the numeric part of their licence plate.

Every driver of a regular car knows this frustration well. You're behind a big SUV or Minivan and you can no longer see what's happening ahead of you, the way you can with ordinary cars. This is not simply because the ordinary cars are shorter, it's because you can see through the windows of the ordinary car -- they are at your level.

More cars are being made "drive-by-wire" where the controls are electronic, and even in cars with mechanical steering, throttle and brake linkages, there also exist motorized controls for power steering and cruise control. (It's less common on the brakes.)

As this becomes more common, it would be nice if one could pop in a simple, short duration control console on the passenger's side. It need not be large, full set of controls, it might be more of the video game console size.

Transit is of course more efficient than private cars, many people on one vechicle. But because a round-trip for a couple or family involves buying 4 to 8 single tickets, couples and families who have cars will often take their cars unless parking is going to be a problem. For example, for us to go downtown it's $6 within SF. For people taking BART from Berkeley or Oakland it's $13.40 for 2 people. Makes it very tempting to take a car, even if it costs a similar amount (at 35 cents/mile, 15 of those for gasoline in a city) for the convenience and, outside of rush-hour, speed.

Through the SV100 I was given an interesting product called the [Trafficgauge](http://www.trafficgauge.com/" rel="nofollow) to review. It's a small thick-PDA sized live map of the highways of your area, with indicators as to where there are traffic slowdowns. They cover about a half dozen cities.

I've been writing a bunch about transportation of late, and I got the chance to have lunch with Robin Chase, founder of Zipcar, and talk about the economics.

She proposes that we really need to make the true cost of our transportation visible to solve many of our problems (congestion, pollution, etc.) It's often been described just how much of a subsidy the U.S. and in particular California gives to the car driver, but to most people it's not too visible.

She's particularly interested in changing the rules on parking. We subsidize parking a lot. Most people are aware of the use of roadsides for free or cheap parking on public land. Robin proposes getting rid of the requirements that force building developers to provide adequate parking for their building. Most people think these are a good idea, because otherwise developers would not provide parking, and the cars coming to the building would suck up all available parking in the area and there would quickly not be any.

George Carlin once proposed a system where people would shoot suction cup darts at cars when they did something annoying, like cutting you off, and if you got too many darts the cops would pull you over. Another friend recently proposed a lot of interest in building some sort of reputation system for cars using computers.

Though Carlin's was a satire, it actually has merits that it would be hard to match in a computerized system. Sure, we could build a system where if somebody was rude on the road, you could snap a quick photo of their licence plate, or say it into a microphone or cell phone for insertion into a reputation database. But people could also just do this to annoy you. There's no efficient way to prove you actually were there for the rude event. The photos could do that but it's too much work to verify them. The darts actually do it, since you could not just stick them on my car when I'm stopped, or I would pull them off before driving.

One problem I want to solve with such a system is the selfish merge. We've all seen it -- lanes are merging, and the cooperating drivers try to merge early. Then the selfish drivers zoom ahead in the vanishing lane until they get to its end. And always, somebody lets them in. Selfishly zooming up does get you through the jam faster, but at the same time these late mergers are a major contributor to the very jam they are bypassing.

We'll never stop people from letting in the drivers, and indeed, from time to time innocent drivers get into the free lane because they are not clear on the situation or missed the merge.

...More...

Here's an idea I had years ago and tried to promote to some of the earliest wireless companies, such as Metricom, without success. I just posted it on Dave Farber's IP list, so I should write it up again for my own blog...

We risked running low on fuel today, and saw the car sputter briefly while going up a hill. Made it to the gas station fine, in fact with a gallon to spare, it seems.

I've been thinking more about environmental economics since I blogged about retail carbon credits. I was surprised about how cheap (some would say unrealisticly cheap) wholesale credits are -- about $2.20 per tonne of CO2. (Update: This price keeps changing. The U.S. price is clearly out of whack down to just 25 cents per tonne in 2009. The European price has declined too, from $20/tonne when I wrote this to $14/tonne in fall 2009.)

Today, many of my friends have bought a car like the Toyota Prius, feeling they are doing their bit to help the environment by burning less gas. The Prius costs around $3,000-$6,000 more than a comparable old-style engine car (in part because high demand keeps the price high), and the savings on gasoline don't justify it on a financial basis unless you do nothing but drive all day. So the main reason to buy it is to help the environment and to make a statement before your peer group. The Camry Hybrid, which gets 32mpg instead of 23mpg costs about $5,000 more than the regular Camry.)

Problem is, there's an argument that you're hurting the environment, counterintuitive as that sounds. And no, it's not just the unanswered questions about recycling the fancy batteries in the Prius when they fade, where fairly positive results have been returned so far. Read on...

After we picked up our rental car in Darwin in the Northern Territory of Australia, the blasting heat told us we would like a cooler full of drinks on our 3 day road trip through the outback. So we stopped at a Woolworths and picked up one of those terrible foam coolers, ice and some drinks. There was no bar code on the cooler so we wasted what seemed like 10 minutes in the checkout because the clerk wasn't authorized to ring up an item as general merchandise. (Hint to stores: I know you're scared of your cashiers stealing from you but this is ridiculous.)

You may have heard of the idea of pollution credit trading. I've been pointed to two firms that are selling CO2 credits on the retail level for individuals, to offset the output from driving a car, heating a house etc.

I'll get into the details on how it works a bit below, but if you have a car like mine that is putting out 5 metric tons of CO2 each year, you can for a low price (about $50, which includes a whopping markup) pay a factory somewhere to cut their own output by 5 tons, meaning that net, you are causing zero emissions. Which means you are reducing total emissions by a lot more than you would by switching to a Prius, and you are doing it at a vastly lower cost. (This doesn't mean you shouldn't drive a Prius, it just means this is a lot more effective.)

Normally pollution credits are traded only by the big boys, trading contracts with hundreds or thousands of tonnes of emissions. The retail firms are letting small players get in the game.

This is a fabulous idea, in theory at least, and also a great, if sneaky gift idea. After all, if you buy the gift of not polluting for your loved one all they get is a bumper sticker and a good feeling. At least it's better than giving to The Human Fund in their name.

Here's the catch. I went and priced the credits, and while www.certifiedcleancar.com wanted $50 to credit my car, the actual price of credits on the Chicago Climate Exchange is about $2.16 per tonne of CO2, or about $8 for my actual output as they calculated it. One expects some markup, of course, and even some profit for the company selling the retail credits, but this is nuts. I called the other company, Terrapass and got reasonably frank answers. First of all, they claim they invest more in wind power and other truly non-polluting forms of energy more than they just buy carbon credits. Secondly, this is still a small volume thing, and most of the costs are not the credits, but the $20,000 or so to become a member of the exchange, or so I was told. And of course, in small volumes, administrative costs can swamp the real costs.

Another outfit I found is carbonfund.org which is non-profit and cheaper. In some sense since people buy these out of guilt rather than compulsion (they were meant to be forced on polluters to give money to non polluters and make a market) non-profit might make sense, but they are also supposed to be a real market.

Still, if I pay $50, I would love for my $50 to mostly go to reducing pollution, not mostly to administration. Usually when exchanges are expensive there are members who will trade for you at much more modest markups. The folks at Terrapass said they were not yet profitable at the current prices.

And it is such a good idea. Read below for more on pollution credits.

Recently, I discovered something that others have known for a while but many don't know. Namely that effectively all modern cars that say they should use Premium (high-octane) gasoline run perfectly fine on regular. Since the early 90s, cars have had more advanced carb/fuel-injector systems which adjust to the octane of the gas and don't knock. Like an idiot, I've been filling my car with premium. The engineers at all the major car vendors have confirmed this.

Many are commenting on the gasoline shortages and price increases involved with hurricane evacuation and other emergencies. Some people can't get gas to get out of the city. Others full up giant tanks even when they don't need it. Stations raise prices as supply drops and demand increases, as per the normal rules of the market. Some suggest the stations be price-controlled to stop this, but that would only result in even more gas hoarding by the public.

Every time I take an RV trip (ie. each Burning Man) I come up with more observations. The biggest one is that it cost $360 in gasoline to go from the bay area to the black rock desert, about 800 miles. And that's at a price still well below world price. The RV owner said he was planning to get out of the business, people no longer want to pay the gas price.

I recently picked up a surplus battery-powered motor assist for a bicycle, and it's a lot of fun. Due to lower power you have to start peddling to 3mph and then it can run the bike for 10 miles at 10mph (for normal weight people, not me.)

Mapping programs, and fancy GPSs come with map databases that will, among other things, plot routes for you and estimate the time to travel them. That's great, but they are often wrong in a number of ways. Sometimes the streets are wrong (missing, really just a trail, etc.) and they just do a rough estimation of travel time.

Ok, this idea will make no sense to those who have not gone RV camping. RVs have 3 water tanks -- one for fresh water, one for the toilet sewage (known as "black water") and one for the other drains (shower, sinks) known as "grey water." When you camp in unserviced campsites for a while you become very aware of the capacities of your tanks.

However, the RV uses the fresh water tank to "flush" the toilet. It seems to me that with a small extra water pump, one could use the grey water, or a mixture -- grey with a final spurt of fresh to rinse the bowl.

RVs don't really flush the toilet, that would use way too much water. You rinse the bowl after #1 and you pre-fill the bowl before #2 and rinse later.

Having completed a long fly-n-drive road trip, I have some lessons and observations.

1. If you will be driving a lot, use a rental car even if leaving your own city. We put 3000 miles on our rental car for $300 -- far less than the depreciation cost would have been on my own car.

2. It's great to have a cooler in the car, you can buy perishables and get cold drinks when you want them, but forget about those $5 styrofoam coolers for any long trip. Within a few days ours was leaking, we fixed it by putting a plastic bag inside and out, but they are not very sturdy. There are collapsible coolers and we have one but didn't have luggage room. You can buy a cheap solid cooler for under $20 at wal-mart or Costco, but it seems wasteful to throw it away. If you have extra luggage, you can fill a cooler with stuff, duct tape it and check it as luggage, however.