Bikes & Cars...

I was at an event with my fellow automotive journalists last week, two of whom were down from Vancouver, BC. Conversation turned to fuel economy, as it always does these days, whether you write about cars for a living or not.

The Canadians talked about their cars getting "litres per 100," which took me a minute to figure out. Like most countries that use the metric system, Canadian fuel efficiency is measured in the number of liters it takes them to travel 100 kilometers. This is exactly backward from the U.S. convention of measuring the number of miles our cars can travel on one gallon of gas. 

It turns out the Canadian system gives a better measure of efficiency, according to researchers at Duke University. The team made this one-question quiz to demonstrate how our intuition fakes us out when talking about miles per gallon, as opposed to gallons per mile. 

The article explains the math, which isn't all that complicated, but there's also a handy table so that we can see at a glance how the conversion helps consumers understand their vehicles' fuel usage. A car that gets 20 mpg, to use a pretty common rating for an example, uses 5 gallons per 100 miles driven. A car that gets 30 mpg uses only 3.3 gallons per 100 miles -- a savings of almost 2 gallons per mile, or about $8.50 these days.

But say you're already a Ford Fusion four-cylinder fan getting 30 mpg, or 3.3 gal/100, and you want to upgrade to a Toyota Prius. The hybrid would get about 45 mpg, or 2.2 gal/100, which only saves you 1 gallon of gas, or about $4.30. That slim difference might be enough to get you to keep the Focus, while the mid-sized sedan owner in the last example would do well to get a more efficient vehicle.

All of this is a great way to save money on gas, but let's not lose sight of the fact that every gallon of gasoline we don't use in our cars is one less reason to start drilling for oil willy-nilly. For once, saving money is about saving the planet. 

By the way, our Canadian friends are paying CAN$1.40 a liter these days, or US$5 a gallon.

Photo by caribb.