A University of Michigan physicist and a research scientist are questioning the belief that bigger and heavier vehicles are automatically safer than other cars and trucks.
U-M physicist Marc Ross and Tom Wenzel, a research scientist at Lawrence Berkeley National Laboratory (LBNL), recently released a report which shows that vehicle quality is actually a better predictor of safety - both for the driver and for other drivers - than weight. The two will discuss their results at a briefing at LBNLs Washington, D.C. office on July 30.
"Safety is a challenging concept. It includes the design of the car itself, driver demographics and behavior, the kinds of roads, the time of day - a whole host of factors," Ross said. "What we need to do is move away from the idea that bigger and heavier vehicles are automatically safer."
Recent Senate hearings on Corporate Average Fuel Economy standards focused on the increased risk Americans would face if they had to give up their SUVs for vehicles that weigh less. "We set out to see whether that risk is real, whether SUVs really are safer than cars. The answer, by and large, is no," Ross said.
The first major result Ross and Wenzel found is that SUVs are no safer for their drivers than cars. Popular midsize cars, minivans and import luxury cars have the safest records, while SUVs are about as risky as the average midsize or large car, and are no safer than many compact and subcompact models. The researchers defined "risk" as the number of deaths per year per million vehicles.
Other studies have not considered combined risk, which looks at both risk to the driver of the model in question and risk to the drivers of all other vehicles involved in crashes with the model in question. The study found that, when measuring the combined risk, most cars are safer than SUVs, while pickup trucks are much less safe than all other types of vehicle.
"Clearly the characteristics of the drivers of certain types of vehicles also have a strong effect on their safety," Ross said. "However, it is not clear exactly what that effect is, and the age and sex of drivers do not fully explain these results." Some of the safest subcompacts also have a high fraction of young male drivers. At the other extreme, elderly drivers dominate certain large cars but there is no clear pattern suggesting that those cars pose especially high risk to drivers of other cars as a result.
The Chevy Corvette illustrates that both vehicle design and driver behavior can be important. Like drivers of other sports cars, Corvette drivers are much more likely to be killed than drivers of other types of cars. But although Corvettes are often driven dangerously, and are very risky for their own drivers, the risk to drivers of other vehicles is low in collisions with Corvettes. The low-slung design and plastic body of the Corvette probably account for its low risk to others.
To determine quality, Ross and Wenzel used quantifiable parameters such as new car price, used car price, Consumer Reports safety ratings, and country of origin. "It is extremely difficult to determine the inherent safety of a vehicle type or model because it is too hard to separate the contribution of driver characteristics and behavior from the contribution of vehicle design. We can say, however, that quality is a much better predictor of safety than weight," Ross said.
"It turns out that relatively inexpensive light cars do tend to be unsafe, but more expensive light cars are much safer, and are as safe as heavier cars and SUV models. In any event, the argument that lowering the weight of cars to achieve high fuel economy has resulted in excess deaths is unfounded. If designers pay careful attention to safety in vehicle design, smaller cars can be, and indeed have been, made as safe as larger ones," Ross said.
Judy Steeh | EurekAlert
New players, standardization and digitalization for more rail freight transport
16.07.2018 | Fraunhofer-Institut für System- und Innovationsforschung (ISI)
A helping (Sens)Hand
11.04.2018 | Fraunhofer-Institut für Arbeitswirtschaft und Organisation IAO
The Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT) in Arizona released its first image of the surface magnetic field of another star. In a paper in the European journal Astronomy & Astrophysics, the PEPSI team presents a Zeeman- Doppler-Image of the surface of the magnetically active star II Pegasi.
A special technique allows astronomers to resolve the surfaces of faraway stars. Those are otherwise only seen as point sources, even in the largest telescopes...
Researchers at Chalmers University of Technology and the University of Gothenburg, Sweden, have proposed a way to create a completely new source of radiation. Ultra-intense light pulses consist of the motion of a single wave and can be described as a tsunami of light. The strong wave can be used to study interactions between matter and light in a unique way. Their research is now published in the scientific journal Physical Review Letters.
"This source of radiation lets us look at reality through a new angle - it is like twisting a mirror and discovering something completely different," says...
New research group at the University of Jena combines theory and experiment to demonstrate for the first time certain physical processes in a quantum vacuum
For most people, a vacuum is an empty space. Quantum physics, on the other hand, assumes that even in this lowest-energy state, particles and antiparticles...
Physicists in the EPic Lab at University of Sussex make crucial development in global race to develop a portable atomic clock
Scientists in the Emergent Photonics Lab (EPic Lab) at the University of Sussex have made a breakthrough to a crucial element of an atomic clock - devices...
Every year earthquakes worldwide claim hundreds or even thousands of lives. Forewarning allows people to head for safety and a matter of seconds could spell...
11.03.2019 | Event News
01.03.2019 | Event News
28.02.2019 | Event News
19.03.2019 | Physics and Astronomy
19.03.2019 | Life Sciences
19.03.2019 | Physics and Astronomy