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What is the calculated correlation between NHTSA vehicle safety score and vehicle weight. I don't know this, but suspect that it is a less significant factor th

What is the calculated correlation between NHTSA vehicle safety score and vehicle weight. I don't know this, but suspect that it is a less significant factor than you imply. Add that the Tesla is 1000lbs+ of battery. Safety is engineering and materials. More materials help, of course, but more materials without the engineering simply equals more kinetic energy. There are vehicles from big SUVs to tiny SMART cars doing superbly on crash tests now.

chemmail 13y ago
Weight has a small impact, but you have to remember the low of geometric scaling.
sbierwagen 13y ago
Amusing that you mention the Smart Fortwo. http://www.iihs.org/news/rss/pr041409.html http://www.iihs.org/news/rss/pr041409.html ARLINGTON, VA — Three front-to-front crash tests, each involving a microcar or minicar into a midsize model from the same manufacturer, show how extra vehicle size and weight enhance occupant protection in collisions. These Insurance Institute for Highway Safety tests are about the physics of car crashes, which dictate that very small cars generally can't protect people in crashes as well as bigger, heavier models. "There are good reasons people buy minicars," says Institute president Adrian Lund. "They're more affordable, and they use less gas. But the safety trade-offs are clear from our new tests. Equally clear are the implications when it comes to fuel economy. If automakers downsize cars so their fleets use less fuel, occupant safety will be compromised. However, there are ways to serve fuel economy and safety at the same time." http://www-nrd.nhtsa.dot.gov/Pubs/808569.pdf‎ http://www-nrd.nhtsa.dot.gov/Pubs/808569.pdf‎ Large vehicles have historically been more stable and provided more protection for their own occupants than small ones, but they presented a greater hazard to other road users. Between 1985 and 1993, the population of light trucks - pickups, sport utility vehicles (SUV) and vans - increased by 50 percent in the United States. Since the major downsizing of passenger cars during 1975-82, light trucks have had a substantial and growing weight advantage over cars. By 1992, the number of fatalities in collisions between cars and light trucks exceeded the number in car-to-car collisions In car-light truck collisions, 80 percent of the fatalities are occupants of the cars. That raises the question whether the growth in the number and weight of light trucks is having an adverse impact on the safety of passenger car occupants and other road users, possibly exceeding any safety benefits of the vehicle-weight increases for the occupants of the trucks. Vehicle safety is complicated, obviously, and vehicle weight isn't the only variable of merit, obviously. (See http://energy.lbl.gov/ea/teepa/pdf/aps-ppt-wenzel.pdf‎ http://energy.lbl.gov/ea/teepa/pdf/aps-ppt-wenzel.pdf‎ ) But all things being equal, in a head on collision between two identical vehicles, save that one weighs a thousand pounds more than the other, the heavier car is going to win.
- corresation 13y ago
  But all things being equal Rater irrational requirement, given that we're talking about engineering. It short circuits the entire conversation. In any case, I find it odd that you find my reference of the Smart "humorous". While the IIHS held their results as demonstrating bigger versus smaller, in actual reality it primarily demonstrated more expensive versus less expensive -- there is no great confusion that less expensive cars often sacrificed safety, and this was true at all vehicle sizes (e.g. some early budget Kia minivans and SUVs were deathtraps). It seems to have mostly passed now that even economical cars like the Cruze are posting stellar results. But let's assume that a greater weight, by itself, equals better safety. So would that Volvo do better than the Tesla if they filled the trunk full of concrete blocks? Note that I didn't say that weight doesn't correlate with safety, but that it doesn't correlate nearly as strongly as you seem to imply -- e.g. saying that a large sedan is 1000lbs heavier than another large sedan in no way, I would guess, leads to a conclusion that it will also do better in safety tests.

chemmail 13y ago

Weight has a small impact, but you have to remember the low of geometric scaling.

sbierwagen 13y ago

Amusing that you mention the Smart Fortwo. http://www.iihs.org/news/rss/pr041409.html http://www.iihs.org/news/rss/pr041409.html ARLINGTON, VA — Three front-to-front crash tests, each involving a microcar or minicar into a midsize model from the same manufacturer, show how extra vehicle size and weight enhance occupant protection in collisions. These Insurance Institute for Highway Safety tests are about the physics of car crashes, which dictate that very small cars generally can't protect people in crashes as well as bigger, heavier models. "There are good reasons people buy minicars," says Institute president Adrian Lund. "They're more affordable, and they use less gas. But the safety trade-offs are clear from our new tests. Equally clear are the implications when it comes to fuel economy. If automakers downsize cars so their fleets use less fuel, occupant safety will be compromised. However, there are ways to serve fuel economy and safety at the same time." http://www-nrd.nhtsa.dot.gov/Pubs/808569.pdf‎ http://www-nrd.nhtsa.dot.gov/Pubs/808569.pdf‎ Large vehicles have historically been more stable and provided more protection for their own occupants than small ones, but they presented a greater hazard to other road users. Between 1985 and 1993, the population of light trucks - pickups, sport utility vehicles (SUV) and vans - increased by 50 percent in the United States. Since the major downsizing of passenger cars during 1975-82, light trucks have had a substantial and growing weight advantage over cars. By 1992, the number of fatalities in collisions between cars and light trucks exceeded the number in car-to-car collisions In car-light truck collisions, 80 percent of the fatalities are occupants of the cars. That raises the question whether the growth in the number and weight of light trucks is having an adverse impact on the safety of passenger car occupants and other road users, possibly exceeding any safety benefits of the vehicle-weight increases for the occupants of the trucks. Vehicle safety is complicated, obviously, and vehicle weight isn't the only variable of merit, obviously. (See http://energy.lbl.gov/ea/teepa/pdf/aps-ppt-wenzel.pdf‎ http://energy.lbl.gov/ea/teepa/pdf/aps-ppt-wenzel.pdf‎ ) But all things being equal, in a head on collision between two identical vehicles, save that one weighs a thousand pounds more than the other, the heavier car is going to win.

corresation 13y ago
But all things being equal Rater irrational requirement, given that we're talking about engineering. It short circuits the entire conversation. In any case, I find it odd that you find my reference of the Smart "humorous". While the IIHS held their results as demonstrating bigger versus smaller, in actual reality it primarily demonstrated more expensive versus less expensive -- there is no great confusion that less expensive cars often sacrificed safety, and this was true at all vehicle sizes (e.g. some early budget Kia minivans and SUVs were deathtraps). It seems to have mostly passed now that even economical cars like the Cruze are posting stellar results. But let's assume that a greater weight, by itself, equals better safety. So would that Volvo do better than the Tesla if they filled the trunk full of concrete blocks? Note that I didn't say that weight doesn't correlate with safety, but that it doesn't correlate nearly as strongly as you seem to imply -- e.g. saying that a large sedan is 1000lbs heavier than another large sedan in no way, I would guess, leads to a conclusion that it will also do better in safety tests.