Safety Over Fuel Economy?


In a previous column, I raised the question of how consumers will react to a new generation of Corporate Average Fuel Economy-mandated high-tech, higher-mileage, smaller and less safe vehicles. This has stirred up some debate and is a question I will explore in more depth in future columns. For now, I will talk more fully about the issue of safety. Safety ties to the issue of CAFE, as it is believed that one of the ways that car companies will respond to higher fuel-economy standards is to reduce the weight of vehicles offered. Lower weight equates directly to higher mileage. The ways to accomplish a weight loss are to offer smaller vehicles or to build vehicles using lighter-weight materials (high tensile steel, aluminum and particularly carbon composites) — or to build vehicles employing a combination of smaller size and lighter materials. These materials offer real fuel savings, but they also raise a vehicle's cost.

Over the years, studies have generally shown that larger, heavier vehicles are safer in the event of an accident than smaller lighter vehicles. I say generally as safety is a complex topic. Here I am focusing on lower rates of injury or fatalities in the event of an accident. It gets complicated as accidents frequently involve two or more vehicles. When one of the involved vehicles is large and the other is small, you would see a different outcome than when both are small or when both are large. It has also been shown that the shape of the vehicles involved can be significant. We can even debate whether it is the vehicle's size that matters, or its mass -- or perhaps it's both.

Even acknowledging the complexity of the issue, we can draw some general conclusions. When considering the vehicles that manufacturers will have to offer in the future, it is also worth noting that the trend over the past decade or so is clear. The average vehicle is getting heavier -- by almost 1,000 pounds between 1991 and 2011. This is because meeting safety standards generally adds weight with the addition of air bags or incorporating roll-over cages for example. Another factor for the weight gain is that consumers continually demand more features on their vehicles. I mention this because when we assume that vehicles will be smaller and lighter in the future we should be clear. This is a marked reversal of what we have seen over the past 20-plus years.

We can have a vigorous debate about the actual size and weight of vehicle in the years to come. Will the batteries in electric vehicles and hybrids actually push up weight? Will new ways of fabricating carbon composites allow greater rates of adoption? For the purposes of discussion, however, we can draw some generalities. To start with, I am drawing upon the National Highway Traffic Safety Administration's (NHTSA) Fatality Analysis Reporting System (FARS) database of fatalities and the Insurance Institute for Highway Safety's (IIHS) recent status report. The IIHS has done a nice job of showing how fatalities increase with declining weight. The study pointedly states that SUV drivers are among the least likely to die in a crash.

Our analysts did a simple extrapolation using this data. If we assume that new light duty vehicle sales in 2020 are 17 million units and the average vehicle weight has dropped by 1,000 lbs, then the data shows that 240 extra deaths will occur. And this number increases each year. Assuming 17 million units are sold each year, the increase would be another 240 deaths -- 240 in 2020, 480 in 2021, etc.

We can quibble about the assumptions. Perhaps the reduction in weight will not be 1,000 pounds, although vehicles would likely be trending heavier without the new standards. Perhaps we will be selling more than 17 million new vehicles. (Let's hope so.) Perhaps new safety technologies reduce crash rates. You can do your own math. The point is that when we want higher mileage and fewer fatalities and injuries, we are pulling in opposite directions. That's something we should think through.

Jeremy Anwyl: Vice Chairman of Edmunds.com. Follow @JeremyAnwyl on Twitter.

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