The latest statistics show they’re definitely getting heavier — no, not Americans, their cars. Automobiles driven in the United States packed on 125 pounds from 1968 through 2001, according to the National Highway Traffic Safety Administration, and that’s just the estimate of the pork heaped on by new safety equipment.
Realizing the need to slim down, carmakers have started rolling out concept cars that explore the potential of lighter-weight vehicles to save on gasoline while still protecting drivers in the event of a crash. The Environmental Protection Agency says that a 10 percent reduction in car weight yields a 7 percent reduction in fuel consumption.
Hyundai’s “QarmaQ” concept car, introduced this week at the Los Angeles auto show, is a case in point. It uses plastic from 900 recycled bottles to make its hood, doors and other parts, shaving 132 pounds of weight off the weight of the same vehicle made with conventional car-building materials, like steel and aluminum.
Toyota was even bolder at last month’s Tokyo Motor Show, showing its 1/X concept, which is made of strong, light carbon fiber. The 1/X name is a reference to the idea that, in terms of weight, the car is a fraction of a regular car. The 1/X is one-third the weight of a fuel-efficient Prius and has an engine that’s one-third of the size, burning one-third the amount of fuel.
What’s not apparent from the car’s specifications is that the 1/X is also a fraction the size of a Prius. Seen in person on the show floor, the exotic concept more closely resembled a golf cart than a modern car, but it served the purpose of demonstrating the potential of cutting weight to save on gas.
“The significance of the 1/X shouldn’t be understated,” insists Michael Brylawski, practice leader of the transportation innovations group at the Rocky Mountain Institute, a groups focused on environmental issues. “With it, Toyota is saying the next frontier is going to be ‘lightweighting.’”
It needs to be. While the NHTSA’s research only shows the increase in car weight because of the addition of more safety gear up until 2001, the total weight increase in cars has only accelerated in the past six model years (see chart for examples).
Carmakers point to crash protection and comfort amenities as the automotive carbs and trans fats contributing to weight gain. An “increasing requirement for safety” is the main factor pushing up car weight, according to Tom Lane, vice president of product planning for Nissan.
When was the last time you bought a car without power windows and door locks, for example? Those parts require heavy electric servos, and their use mandates bigger, heavier alternators and batteries. The Lexus LS460 might be the current reigning gadget champ, with 125 electric servo motors on board.
Carmakers strive not only to meet NHTSA’s federal crash test requirements but also to earn a top score on the tougher Insurance Institute for Highway Safety offset frontal crash test. Both groups have added tests for side impact protection and rear-end collisions, and manufacturers have braced, reinforced and armored their cars in response.
The result is a wave of porky, pavement-crushing steamrollers that are harder to accelerate, turn and stop. That in turn necessitates bigger engines, brakes and tires, which add still more weight. And the really dangerous part is that bigger cars strike other vehicles harder in a crash, inflicting more damage.
What’s more, heavier cars have a harder time passing crash tests and protecting occupants in crashes because all of that weight plowing ahead increases the amount of energy the crush space at the front of the car must absorb on impact.
Light, strong materials like carbon fiber provide impact protection without adding much mass. The material is already prohibitively expensive, and now Boeing is ravenously consuming the world’s supply of it to build its 787 Dreamliners, reports Brylawski.
The need for high-strength steel is making that critical commodity hard to get too, according to Nissan’s Lane. But these are short-term obstacles that will be overcome, he insists.
“You will see vehicles that weigh less than their predecessors,” Lane pledged. Nissan plans to use steel and aluminum to trim weight in coming years. Even carbon fiber is a possibility, he added.
Today, carbon fiber is not suitable for mass production because it must be baked in an oven to harden. But thermoplastic resins would let manufacturers form the parts hot so they harden as they cool, making mass production practical, said Brylawski.
The possibility of such a high-tech “gastrobypass” for cars is still more than a decade away, he acknowledged, but it will happen eventually.
“Automotive scale manufacturing of carbon fiber is not an ‘if,’ but a ‘when,’” he said.
When it happens, look for dramatic changes in mass and efficiency. Meanwhile, we just have to hope that next year’s models will muster the willpower to turn away from the gadget buffet and shed those first pounds that will at least turn the weight trend in the other direction.