Yesterday was a good example of why it is important to always clean your car’s windshield completely before driving. I didn’t see the accident take place, but a car that was parked on the street was pushed about fifty feet down the road, onto the grass, and into a tree. This caused quite a bit of damage to both ends of the car. The driver that hit the parked car left the scene. A few minutes later another neighbor showed up with a smashed bumper. What I think happened was this:

(Using standard cryptography alphabetical stand-in names)

It was warm but snowing (‘slushing’) just enough that car windows needed to be cleaned before driving. Alice was in a hurry and didn’t clean her windshield. In the half block between Alice’s house and where Bob was parked, Alice accelerated too much. I can tell Alice was driving too fast for a neighborhood street by how far Bob’s car was pushed given the relative masses of the two cars. Alice must have not cleaned her windshield, preventing her from seeing Bob’s car, even though it is common for a car to be parked where Bob’s was. Alice then drove back up the block, cleaned the snow off the car, and came back.

Now, imagine that instead of a parked car, it was one of the many cyclists or joggers in the neighborhood. So, please, completely clean and defrost your car’s windows before driving.

Why is this important? The current law uses a subjective definition of safe passing separation. What a cyclist feels is a safe distance isn’t necessarily the same as what a driver or police officer feels is a safe distance. Drivers often believe the safe distance is much less than it is, and make dangerous passes. Since the safe distance is no less than three feet, and many people don’t realize this, we need the minimum separation to be explicit in the motor vehicle code.

You can help promote this important safety law by filling out this survey from Bicycle Indiana, and by writing your state representatives. And while you are at it and if you live in Allen County, fill out the City of Fort Wayne Trail Survey.

With or without an explicit legal definition, remember to only make safe passes:

Notice the steps of the safe pass:

1. Begin to move over well before reaching the cyclist.
2. Pass at a safe distance. Keep a minimum of three feet between the closest points of the car and the bicyclist. At high speeds and with large vehicles the minimum safe separation is larger. Don’t forget about your mirrors.
3. Move back into the lane well after passing the cyclist. Don’t forget to leave room for your trailer.

Choosing a gas station to attempt to control the source of your gas is moot:

Can I Tell Which Companies Purchase Imported Crude Oil or Gasoline?
While EIA cannot identify which companies are selling imported gasoline, we do collect data on which companies import crude oil and refined products. However, the fact that a given company imported crude oil or gasoline does not mean that those particular imports will end up being sold to motorists as that company’s brand of gasoline. This is because gasoline from different refineries is often combined for shipment by pipeline, and different companies owning service stations in the same area may be purchasing gasoline at the same bulk terminal.
—US Energy Information Administration, “Oil Imports and Exports – Energy Explained, Your Guide To Understanding Energy”

Oil is a fungible commodity, so what matters to price is the world demand. (And world oil futures speculation and local distribution costs…)

Since the forwarded message makes such a point about not supporting Saudi Arabia: ~8.7% of oil used in the US is from the Persian Gulf, including ~5.3% from Saudi Arabia. The top sources of oil used in the US are:

The numbers in the email for which companies import oil from the Middle East are also wrong. For example, it lists Valero as importing no Middle Eastern oil, when in fact the Persian Gulf is the source of 24% of their oil. BP is also quoted as 0%, when it is actually 10 or 44% depending on the region. The email also lists Amoco as an importer from the Persian Gulf, when it is a division of BP, which it lists as not an importer from the Persian Gulf. Several others on the list of 0% each only supply fractions of a percent of US oil. Besides, as shown above, the original source of the oil doesn’t matter to price. Even if we could shift where we get our oil, that just shifts who is buying from where, with the total sold remaining constant.

What matters is the total oil used. A quick calculation shows that to decrease the amount of oil used in the US by the amount we import from Saudi Arabia, all you have to do is increase average fuel economy by a bit over one mile per gallon. Most people can improve their mileage by more than that by just learning to drive their current car slightly better. In fact, we may get there before most people learn to drive properly: last year’s update to the CAFE standards finally started us back on track to improve fuel economy by more than this amount.

Remember, the solution is efficiency, not which gas station you buy from!

After I wrote this, I found that a variant of this particular email has been around for years, and that Snopes debunked it six years ago.

Hmm… maybe I should debunk some of The Heritage Foundation’s claims about oil prices too…

Today I found another example why my mistrust of embedded systems is justified. We have a gas convection oven with a fairly sophisticated electronic control. It has a processor that does a good job of keeping the temperature stable and that can do useful things like automatically turn the oven off when the cooking time is complete. After using the oven today, I hit the off button. The gas turned off, then the oven locked up. It was receiving power, and the LED panel was lit, but it was completely unresponsive. I had to use the circuit breaker to reboot the oven. I hope it is designed so that a failure causes the gas valve to close, but it may not.

The crashing oven is relevant to self-driving cars because they are both ubiquitous and potentially deadly systems controlled by embedded processors. If I can’t trust an oven, how much less should I trust a car?

Unfortunately, I would be completely unsurprised if we are eventually forced into self-driving cars. Besides the common unjustified technological optimism, there are the problems of well-meaning safety campaigners and of lawyers. Because the ideal driverless car is perfectly safe, as more cars begin to incorporate more bits of automated driving (eg automatic distance controls), it is likely that there will be campaigns and lawsuits to mandate these features. These will likely add up until we are forced into driverless cars.

While self-driving cars are an interesting research project with some beneficial uses, my experience in maintaining cars and in computer engineering makes me think they are a bad idea for general use. A better solution is to expand the rail system to lower the use of interstate highways, and to design cities where driving is less needed.

GMAC Insurance released their 2010 National Drivers Test results. The findings are interesting:

• If taken today, 18.4 percent of drivers on the road – amounting to roughly 38 million licensed Americans – would not pass a written drivers test exam.
• The national average score was 76.2 percent; a score below 70 percent is considered failing.
• Average test scores in 2010 continue to show a slight trending downward, from 76.6 percent in 2009 to 76.2 percent this year and a drop of almost 2 percent from the national average in 2008 (78.1 percent).
• With Age Comes Wisdom: The older the driver, the higher the test score. Males over 45 earned the highest average score.
• Factoring in margin for error, the average test score was significantly higher among males than females (78.1 percent male versus 74.4 percent female). Females also had a higher failure rate than males (24 percent female versus 18.1 percent male).

I’m not particularly surprised at the results. It can be hard to remember which of several similar answers is correct, which partially accounts for the low score; but this isn’t an excuse on something this important. The way I see it, the results are evidence that nearly one fifth of the licensed drivers in the country should have their licenses suspended until they re-pass their licensing requirements. Even this is optimistic. A survey like this can’t distinguish between book knowledge and its application. How many people can pass the test but never follow the rules afterward? This could be examined by including both the scores on the driver’s written tests and state accident data in the analysis.

Even in the wildly optimistic case that all drivers are able to re-pass the driver’s licensing tests after driving for a few years, it still wouldn’t be enough to ensure safe roads. The driver’s tests are currently only for the absolute minimum required knowledge and skill to drive a car on public roads, safe driving requires much more skill and awareness. A good step toward this level of driving is to take the ABATE or MSF motorcycle safety test. I think that passing one of these courses should be a prerequisite to applying for a car learner’s permit. This would make the roads much safer.

The GMAC test is online so you can try it yourself. Then you should read my page on safe driving around bicycles.

Source: 2010 GMAC Insurance National Drivers Test via AOL Autos via USA Today. Note that this was an online survey.

I never would have guessed, but apparently drivers in Fort Wayne are involved in accidents 16.3% less than the average driver in the 200 most populous cities in the USA. Just think how much safer we could be if Indiana had slightly less easy licensing tests.

Study found through ‘For safe driving, city ranks No. 11’ in the Journal Gazette.

A gallon of gas contains an average of 36.6 kWh. So, if a car gets 25 miles a gallon, it uses 1.46 kWh per mile. So, driving a car one mile is equivalent to keeping a 60 W light bulb on for 24.4 hours. Over one lightbulb-day per mile!

Next, I plotted this equivalency for a wide range of fuel economies, highlighting three locally common cars:

Of course, we (mostly) switched to compact fluorescent bulbs years ago. CFLs use less than a quarter of the energy of an incandescent bulb, and my car does better than 25 mpg; so, for me, driving a car a mile is more like keeping a bulb lit for over five days. Woah.

Anyway, it is an interesting paper showing that many people underestimate the energy consumption of power hungry devices, and overestimate the power consumption of small devices. It’s open access, so you should read it.

Suggested reading: ‘Public perceptions of energy consumption and savings’ (doi:10.1073/pnas.1001509107)

Recommended reading:

• ‘Driver’s ed value doubted: Trained teenagers wreck more often, legislators told’ – Journal Gazette
• ‘Ex-ISU prof urges tougher driving standards’ – Tribune Star

The the definition of light truck in the CAFE standard includes many SUVs and vans. Pickup trucks, SUVs, and vans made up around half of the passenger vehicles sold in recent years. The orange line shows the expected average fuel economy for the current mixture of trucks and cars. Keeping this mix of light trucks and cars will result in the average fuel economy only reaching 33.7 miles per gallon. Reaching the target of 35.5 mpg requires the fraction of new vehicles sold classified as light trucks to drop from one half to around one third. This is shown by the pink line.

From my estimate of the total number of cars and miles driven, I can estimate the gasoline burned, giving the CO₂ produced by all cars and light trucks on the road:

This shows the expected change with and without the new CAFE standard. For the base scenario (without the CAFE update), I included the expected change in the fraction of trucks sold. Notice that after the CAFE standard is constant, the expected CO₂ output resumes its climb. This is due to the predicted population increase, with the number of cars per capita remaining constant. The CAFE update will bring the expected CO₂ production from cars to below 2000 levels for nearly three decades, when population growth catches up with efficiency improvements.

Since I found the expected gasoline consumption with and without the CAFE update, it is easy to find the expected savings in CO₂ emissions:

Notes: The numbers from 2005 to 2010 are estimated based on 2004 levels. These years are estimated because accurate statistics are released a few years late. The scenarios not labled ‘current trucks’ include a decrease in the truck to car ratio starting with 1:1 in 2008 and reaching 1:2 in 2016. The data before 1979 isn’t as accurate as the 1979 to 2004 data, but the effect is negligible after the early ’80s due to the high turnover rate of miles driven.