GREENer HOUSE

I borrowed my neighbour’s Honda CRV yesterday when my car was in for a service. It has automatic transmission with an overdrive on/off button at the end of the shift lever. As I started driving, I noticed a light on the dashboard telling me that the overdrive was off. This got me thinking about the buttons, levers and switches in various cars that should be labeled “waste petrol/save petrol” but are instead given other, less clear labels that drivers may not understand. It did turn out that the owner of the CRV had very little idea what the overdrive on/off button was for. (It also turned out that the overdrive was off because I had inadvertently bumped the button, but I won’t let that get in the way of an informative rant.)

Overdrive switches on automatic transmission cars are far less common than they used to be, but in many makes of cars their replacements have been even more frightening. Overdrive is simply the highest gear on an automatic car, the one at which the wheels are turning faster than the engine. The point of optimum fuel efficiency is the slowest speed at which your car can comfortably drive in this highest, overdrive gear. (Or the highest gear on a manual transmission car.) Losing that gear by turning overdrive off increases petrol consumption by 20 percent or more for highway driving. The only legitimate reasons to turn overdrive off is for engine braking when heading down a steep hill on a highway, or if the automatic is temporarily shifting back and forth repeatedly between top gears, but many people leave overdrive off for extended periods.

In some cars, turning the overdrive off also tells the automatic transmission to let the engine rev higher before shifting into 2^nd and 3^rd gears as well—and so fuel efficiency declines at all speeds. This is the approach used today in many cars that have a switch, button, or lever for “sports mode.” At this setting, the transmission will delay shifting up at every gear, though they will eventually reach the highest gear. The higher revolutions-per-minute will make the engine noisier and less fuel efficient, and the automatic shifting becomes jerkier. (The car will also accelerate faster, but if your main goal is fast acceleration, I’ve already lost you.)

Volvo mercifully has done away with its hideously labeled “Economy/Sport” switch. To a hormonal male, it might as well have read “Pansy/Tough Guy.” Mercedes labels the switch, “Comfort/Sports,” which at least makes economical driving sound a little bit appealing. BMW and Volkswagen have a Sports mode on all of their automatics.

Toyota has done away with Overdrive-Off without replacing it with a Sports mode, and the other manufacturers should follow their lead, in my opinion. I’m generally a timid guy, not suited to the life of an eco-saboteur who would ram a whaling boat or dynamite a logging truck, but if I’m driving someone else’s car, I do them a favour and switch Sports mode off. See if they notice.

The tragic death of South African pop star Lebo Mathosa, after her 4×4 rolled over several times, serves as an apt opportunity to review the myth of SUV safety.

I won’t get into the damage that 4x4s and their emissions do to the environment. No one buys one of these vehicles for the sake of the earth. Nor can I argue with those who find driving an SUV to be psychologically necessary.

According to an article in the New Yorker on SUVs:

… internal [auto] industry market research concluded that S.U.V.s tend to be bought by people who are insecure, vain, self-centered, and self-absorbed, who are frequently nervous about their marriages, and who lack confidence in their driving skills.

There’s not much more I can add to that.

I do acknowledge that there are people who regularly drive on roads that are not passable in normal 2-wheel-drive sedan cars. I just hope that they leave their 4×4 vehicles in the garage as much as possible when they get back to town.

What worries me, though, is that some people are buying 4x4s under the illusion that they are safer than cars. Because they are large and high, they feel safe, but those same characteristics give them the disadvantage when it comes to steering, braking and rolling over.

The definitive work on the subject is a book by Keith Bradsher, “High and Mighty: SUVs: The World’s Most Dangerous Vehicles and How They Got That Way.” A review of Bradsher’s book in the Economist magazine says that SUVs:

… have a kill rate at least three times higher than cars. Poor driving dynamics make them liable to roll over: around 12,000 Americans were killed in SUV roll-overs during the 1990s.

Anyone buying an SUV to haul around their kids should know about a study released this year looking at 4,000 children involved crashes of SUVs and cars. Here are some quotes on the study from the New York Times:

“Our sense was that most people have been assuming [SUVs] were safer and, frankly, we were, too,” said the senior author of the study, Dr. Dennis R. Durbin of the Children’s Hospital of Philadelphia . . .

. . . But with S.U.V.’s, the new study reports, whatever benefits that come with the added weight are erased by the higher risk of rolling over . . .

. . . While rolling over is a danger for both kinds of vehicles, rollovers occurred twice as often in S.U.V.’s, the study found, and children were three times as likely to be injured in rollovers than in other kinds of accidents.

Even if the vehicle does not roll over, many SUVs are built with a rigid design that makes them more dangerous in a crash. The New Yorker article, by Malcolm Gladwell, makes a telling comparison, though it unfortunately does not use South African vehicles in the example:

In a thirty-five m.p.h. crash test, for instance, the driver of a Cadillac Escalade—the G.M. counterpart to the Lincoln Navigator [a large 4x4]—has a sixteen-percent chance of a life-threatening head injury, a twenty percent chance of a life-threatening chest injury, and a thirty-five-percent chance of a leg injury. The same numbers in a Ford Windstar minivan—a vehicle engineered from the ground up, as opposed to simply being bolted onto a pickup-truck frame—are, respectively, two per cent, four per cent, and one per cent.

Why all the quotes from American and European publications? I simply do not see much written about this issue in South Africa. The myth of 4×4 safety is still strong here. The tragedy is the number of people, perhaps including Lebo Mathosa, who thought they were doing themselves a favour by buying a 4×4, who felt safe and secure right up until the moment of their death.

This is a momentous day for the environmentally conscious in South Africa for two reasons: it’s Car Free Day and it’s the South African premiere of “An Inconvenient Truth.”

So far, I’m handling Car Free Day pretty well. My children caught the spirit and walked to school. They even phoned four neighbour children to join them. It’s a 12 minute walk, and I’m embarrassed to admit that we drop and fetch by car far more often than we walk. But that’s what Car Free Day is all about—spurring people to look for ways to break old, car-dependent habits. Whenever we do walk to school, I find that everyone arrives at school in a good mood. I’m sure we’ll walk more in the coming weeks.

I managed to accomplish my only other away-from-home errand today by bicycle. So far, I haven’t been in a car. My wife, however, has driven today, and I know that it’s easy for me, with an office at home. We both commuted by subway when we lived in Washington, DC, but there is no comparison between the modern Metro system there and the public transport available where we live now in Johannesburg. I do have one neighbour who travels to his job at Wits by bus, however, and he doesn’t complain.

Carpooling is another option. I shared a ride to a choir concert this week with a fellow chorister and we vowed to continue our carpool during weekly rehearsals. The Johannesburg government is encouraging carpooling by setting up a database of people who are willing to share rides at RideShare or RideSmart. (They don’t seem to have made up their mind what to call it.) If you give them your home location, work location and work hours, they will tell you who else works similar hours and lives and works within 1.5 kms of you.

I would love to hear from anyone who had an interesting experience going Car-Free or who has tried RideSmart. I also would like to let people know about what similar efforts other cities are making, if any. Click on “comment” below to add your thoughts.

An Inconvenient Truth opens today at Cinema Nouveau theatres in Johannesburg, Pretoria, Durban and Cape Town. This documentary explores the issue of global warming, largely through the eyes of dogged environmental campaigner Al Gore. In the U.S., this film was one of the most successful documentaries in years, and received very positive reviews. Yazeed Kamaldien in the Star today dismissed the film as “boring.” Shaun de Waal of the Mail & Gaurdian warmed to it a little bit more, and made it his Movie of the Week.

I can’t judge yet, not yet having seen the film. But it’s worth contrasting Kamaldien’s review with that of Roger Ebert, perhaps America’s best known and most popular reviewer. In the Chicago Sun-Times, Ebert wrote:

When I said I was going to a press screening of “An Inconvenient Truth,” a friend said, “Al Gore talking about the environment! Bor…ing!” This is not a boring film. The director, Davis Guggenheim, uses words, images and Gore’s concise litany of facts to build a film that is fascinating and relentless. In 39 years, I have never written these words in a movie review, but here they are: You owe it to yourself to see this film. If you do not, and you have grandchildren, you should explain to them why you decided not to.

In other words, you owe it to yourself to ignore Kamaldien and make your own judgement.

I was returning from a wonderful trip to Mapungubwe National Park yesterday, and hit a terribly boring stretch of the N1, north of Pretoria. To stay awake, I played with the fuel economy gauge on my Honda Jazz. I usually reset this only when I fill the tank. (Average consumption 6.4 l per 100km if I’m driving, 7.1 if sharing the car with my wife.) Every 15 km, I reset the gauge, and changed the way I was driving.

At 120 kph with the air conditioning on, the gauge said the car was using 7.0 litres per 100 km. With the air conditioning off, this fell to 5.6 litres. This confirmed my habit of rarely using the air conditioner except for hot days on the highway. Even then, I switch it off for uphills—a procedure that I have not vetted with any automotive or air conditioning experts, but it makes sense to me. Keeping the air conditioning off, I tried another 15 kms at 110 kph. Consumption fell to 5.3.

Finally, I tried 100 kph. This was the shocker. I was using only 4.3 litres of petrol per 100 kms. I need to try this again to confirm this result, but if true, I could have saved more than 14 litres of petrol by driving at 100 rather than 120 on a hypothethical highway trip of the same distance. That would spare the atmosphere 35 kilograms of carbon dioxide. (Actually, it’s far more than that, because a third of South Africa’s petrol is derived from coal, so it results in more carbon dioxide, but I haven’t figured out how to calculate that yet.)

Yes, the trip would also have taken just under an hour longer each way, but I was having a pleasant time with my son, working on his history project on Mapungubwe. If I had been listening to a book on CD, I would have been in even less of a hurry. I wouldn’t drive 100 on a busy two-lane highway signposted at 120. Traffic would back up and drivers might start overtaking dangerously. But on a multi-lane, divided highway, 100 is a reasonable—and safer—speed. When I first learned to drive in the States, the legal limit on all highways was considerably lower than 100 kph. (55 miles per hour.)

Try this experiment—or a variation of it—on your own car, if it has a consumption guage. Let us know the results by clicking on “comments” below.