Back in 2008 I wrote a controversial article about whether green transit was a myth in the USA. Today I updated the main chart in that article based on new releases of the Department of Energy Transportation Energy Fact Book 2009 edition. The car and SUV numbers have stayed roughly the same (at about 3500 BTUs/passenger-mile for the average car under average passenger load.)

What's new?

I just landed on a flight from Toronto to San Francisco. If you were inside the USA you may not have heard about the various crazy rules applied to travel to the USA, or at least not experienced them. While we were away the rules changed every day, and perhaps every hour.

It was over 5 years ago that I blogged about a robot that would travel in front of a train to spot cars stuck on the tracks in time to stop.

I recently read a local story about an RV that was demolished while stuck on the tracks here. The couple had time to talk to 911, who told them to get out, and it's not clear from the story but it seems like a moderate amount of time may have passed (a couple of minutes) before their RV was smashed.

I struck a nerve several years ago when I blogged about the horrible beep-beep noise made by heavy equipment when it backs up. Eventually a British company came up with a solution: a pulsed burst of white noise which is very evident when you are near the backing up vehicle but which disperses quickly so it doesn't travel and annoy people a mile away as the beeps do.

After every RV trip (I'm back from Burning Man) I think of more I want RVs to do. This year, as we have for many years, we built a power distribution system with a master generator rather than having each RV run its own noisy, smelly and inefficient generator. However, this is expensive and a lot of work for a small group, it is cheap and a lot of work for a larger group.

There's been a revolution in small generator design of late thanks to the declining cost of inverters and other power conversion. A modern quality generator feeds the output of its windings to circuits to step up and step down the voltage to produce the required power. The output power is cleaner and more stable, and the generator is spun at different RPMs based on the power load, making it quieter and more efficient. With many models, you can also combine the internal output of two generators to produce a higher power generator.

RVs have come with expensive old-style generators that are quieter than cheap ones, and which produce better power, but today they are moving to inverter generators. With an inverter generator, it's also possible to draw on the RV batteries for power surges (such as starting an AC or microwave) beyond what the generator can do.

I'm interested in the potential for smarter power, so what I would like to see is a way for a group of RVs with new generation power systems to plug together. In this way, they could all make use of the power in the other vehicles, and in most cases only a fraction of the generators would need to be running to provide power to all. (For example, at night, only one generator could power a whole cluster. In the day, with ACs running, several would need to run, but it would be very unlikely to have to run all, or even 75% of them.)

RVs all have a fresh water tank. When you rent one, they will often tell you not to drink that water. That's because the tanks are being filled up in all sorts of random places, out of the control of the rental company, and while it's probably safe, they don't want to promise it, nor disinfect the tank every rental.

I recently got a small "pen" which you put in a cup of water and it shines a UV light for 30 seconds to kill any nasties in the water. While I have not tried to test it on infected water, I presume that it works.

Recently, some prosecutors, in efforts to crack down on drunk driving, are pushing for murder convictions. This is happening in the case of really blatant disregard on the part of the drunk drivers -- people with multiple DUIs getting smashed, going out, and killing.

Here are some notes based on my recent trip to Finland, Sweden and Russia. Not about the places -- that will come with photos later -- but about the travel itself.

I've written a few times about the "Selfish Merge" problem. Recently, reading the new book Traffic: Why We Drive the Way We Do by Tom Vanderbilt, I came upon some new research that has changed and refined my thinking.

The selfish merge problem occurs when two lanes reduce to one. Typically, most people try to be "good" and merge early, and that leaves the right lane, which is ending, mostly vacant. So some people zoom ahead of everybody in the right lane, and then merge at the very end. This is selfish in the sense that butting into any line is selfish. Even if overall traffic flow is not reduced (and even if it is increased) the person butting in moves everybody back one slot so they can get ahead by many slots. This angers people and generates more counter-productive behaviour, including road rage, and attempts to straddle the lanes so that the selfish mergers can't move up to the merge point.

In Traffic, Vanderbilt writes of surprising research that changed his mind, which showed that, in simulations, some merging forms provided up to 15% more traffic throughput than proper attempts at a zipper merge. In particular, a non-selfish merge fully using the vanishing lane worked better than the typical butt-in situation described at the top.

In this merge, which I'll call the "slow and fair merge," drivers are told to use both lanes up to the merge-point, and then to fairly "take their turn" at the merge point entering the continuing lane. Nobody is selfish here, in that nobody butts ahead of anybody else, but both lanes are fully utilized up to the merge point.

This problem is complex, I believe, because there is a switch-over point, which I call the "collapse" point. This is the point at which the merge flow becomes high enough that traffic collapses to "stop and go" mode, before and at the merge-point. Before that point, in lighter traffic, there is little doubt (for reasons you will see below) that the "cooperating fast zipper" merge results in the best traffic flow. In particular, there are traffic volumes where you could either have cooperating zipper or "slow and fair" but cooperating zipper would do a fair bit better. There are also traffic volumes where cooperating zipper just isn't possible any more, and we will either have "slow and fair" (which has the best volume) or "selfish merge" which has a worse volume.

Real world experiments show different results from the theoretical. In particular, many drivers, used to the anarchic selfish-merge approach, don't understand fair and slow, even when signs are explicit about it, and so they resist using both lanes and try to merge early. They also try to straddle, devolving to selfish merge. An experiment with digital signs which changed from advising drivers to zipper-merge in light traffic to advising "use both lanes" and "merge here, take your turn" in heavier traffic was disobeyed in fair and slow mode by too many drivers. The experiment ended before people could learn the system.

Ford is making a new car-limiting system called MyKey standard in future models. This allows the car owner to enable various limits and permissions on the keys they give to their teen-agers. Limits included in the current system include an 80 mph speed limit, a 40% volume limit on the stereo, never-ending seatbelt reminders, earlier low-fuel warnings, audio speed alerts and inability to disable various safety systems.

As part of my research into robotic cars, I've been studying the energy efficiency of transit. What I found shocked me, because it turns out that in the USA, our transit systems aren't green at all. Several of the modes, such as buses, as well as the light rail and subway systems of most towns, consume more energy per passenger-mile than cars do, when averaged out. The better cities and the better modes do beat the cars, but only by a little bit. And new generation efficient cars beat the transit almost every time, and electric scooters beat everything hands down.

Note to new readers: This article explores the consequences of using so much fuel to produce our food. If you come out of it thinking it's telling you to drive rather than get some exercise, you didn't read it! But if you like surprising numbers like this, check out the rest of my Going Green section and other sections.

Rental car companies are often owned by car manufacturers and are their biggest customers. As cars get more and more computerized, how about making rental cars that know how to personalize to the customer?

When Hertz assigns me a car, they could load into its computer things like the dimensions of my body, so that the seat and mirrors are already set for me (simply remembered from the last time I rented such a car, for example.) If I have a co-driver, a switch would set them for her. The handsfree unit would be paired in advance with my bluetooth phone.

I wrote earlier this week about selfish merging and traffic jams and this prompted some to ask if the selfish merge is really selfish. Update: There is more and new thinking in this later post on selfish merge being not so selfish.

I have written before about the selfish merge which is a tricky problem to solve. One lane vanishes, and the merge brings everybody to a standstill. Selfish drivers zoom up the vanishing lane to the very end and are let in by other drivers there, causing the backup. The selfish strategy is the fastest way through the blockage, yet causes the blockage.

From time to time I come up with ideas that are interesting but I can't advocate because they have overly negative consequences in other areas, like privacy. Nonetheless, they are worth talking about because we might find better ways to do them.

In many cities, the transit systems have GPS data on the vehicles to allow exact prediction of when trains and buses will arrive at stops. This is quite handy if you live near a transit line, and people are working on better mobile interfaces for them, but it's still a lot harder to use them at a remote location.

Many cities (and airports) have official taxi monopolies. They limit the number of cabs in the city, and regulate them, typically by issuing "medallions" to cabs or drivers or licences to companies. The most famous systems are in London and New York, but they are in many other places. In New York, the medallions were created earlier in the century, and have stayed fixed in number for decades after declining from their post-creation peak. The medallion is a goldmine for its "owner." Because NY medallions can be bought and sold, recently they have changed hands at auction for around $300,000. That 300K medallion allows a cab to be painted yellow, and to pick up people hailing cabs in the street. It's illegal for ordinary cars to do this. Medallion owners lease the combination of cab and medallion for $60 to $80 for a 7-9 hour shift, I believe.

Here in San Francisco, the medallions are not transferable, and in theory are only issued (after a wait of a decade or more) to working cab drivers, who must put in about 160 4-hour shifts per year. After that, they can and do rent out their medallion to other drivers, for a more modest rental income of about $2,000 per month.

On the surface, this seems ridiculous. Why do we even need a government monopoly on taxis, and why should this monopoly just be a state-granted goldmine for those who get their hands on it? This is a complex issue, and if you search for essays on taxi medallions and monopoly systems you will find various arguments pro and con. What I want to get into here is whether some of those arguments might be ripe for change, in our new high-tech world of computer networks, GPSs and cell phones.

In most cities, there are more competitive markets for "car services" which you call for an appointment. They are not allowed to pick up hailing passengers, though a study in Manhattan found that they do -- 2 of every 5 cars responding to a hail were licenced car services doing so unlawfully.

In the SF Bay Area, there are carpool lanes. Drivers of fuel efficient vehicles, which mostly means the Prius and the Honda Civic/Insight Hybrids can apply for a special permit allowing them to drive solo in the carpool lanes. This requires both a slightly ugly yellow sticker on the bumper, and a special transponder for bridges, because the cars are allowed to use the carpool lane on the bridge but don't get the toll exemption that real carpools get.

In one of my first blog posts, I wrote about virtual right-of-way, a plan to create dedicated right of way for surface rail and bus transit, but to allow cars to use the RoW as long as they stay behind, and never in front of the transit vehicle.

I proposed one simple solution, that if the driver has to step on the brakes because of a car in the way, a camera photographs the car and plate, and the driver gets a fat ticket in the mail. People would learn you dare not get into the right-of-way if you can see a bus/train in your rearview mirror.