Randall Parker notes that car fuel-efficiency gains get used for speed and size, not for reducing fuel consumption:
6 speed transmissions, engines that turn off some cylinders while cruising, hybrids, new lighter materials, and other innovations plus the big rise in oil prices were not enough to change the average fuel economy of new cars. Attempts to increase efficiency get undermined in at least 3 ways by consumers:
- People choose bigger cars and SUVs.
- People choose models that accelerate more rapidly.
- People drive more miles.
As Brett Bellmore points out, all this is perfectly predictable, given that,
- the price of gasoline isn’t that much higher than historical levels, when adjusted for inflation, and
- it today represents a smaller fraction of most people’s incomes.
In fact, this is known as Jevons Paradox:
In his 1865 book The Coal Question, Jevons observed that England‘s consumption of coal soared after James Watt introduced his coal-fired steam engine, which greatly improved the efficiency of Thomas Newcomen‘s earlier design. Watt’s innovations made coal a more cost effective power source, leading to increased use of his steam engine in a wide range of industries. This in turn made total coal consumption rise, even as the amount of coal required for any particular application fell.