4 ms·

But how much of that is due to safer automobiles? How has the accident rate been affected?

voakbasda 5y ago
The effects were measured right before and after the speed limits were change, and cars did not magically get a lot safer at that exact same time. Thus, automobile safety seems to be an irrelevant variable in the quoted study.
- Someone 5y ago
  If cars, on average, last 20 years, 10% of cars get replaced in two years time. That can be significant. I also would think cars that get replaced are driven a lot more kilometers per year, so chances are a lot over 10% of all kilometers driven were in newer cars. ⇒ I’m not convinced increasing the speed limit didn’t make roads less safe. Reading https://www.cato.org/sites/cato.org/files/pubs/pdf/pa346.pdf https://www.cato.org/sites/cato.org/files/pubs/pdf/pa346.pdf, fatality rate dropped from about 1.7 to about 1.6. That’s about 6%. Eyeballing figure 1 in https://www.euro.who.int/__data/assets/pdf_file/0015/43314/E92789.pdf https://www.euro.who.int/__data/assets/pdf_file/0015/43314/E..., I see a drop that could be of similar size in the EU, too. ⇒ I’m not convinced increasing the speed limits made the roads less safe, either. In general, highways are about the safest roads, anyways, so you probably would have to look at safety only on those roads with higher speeds to be able to answer the question whether safety went up/down/nowhere.
mikestew 5y ago
There's a two year difference between measurements, as described in the quoted part of the above comment. Cars didn't change that much in those two years*, nor did everyone go out and buy new cars. * Airbags were already mandated in the U. S. at that point, and though I oddly can't find a reference, I believe anti-lock brakes were mandatory at that point, too.
- saila 5y ago
  Reading through this, it doesn't sound like ABS was required in 2009: https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/811182 https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/.... Another source says it's been required (federally) as of 2013: https://knowhow.napaonline.com/what-does-abs-mean-on-a-car/ https://knowhow.napaonline.com/what-does-abs-mean-on-a-car/.
  - mikestew 5y ago
    Man, I could have sworn ABS became mandated standard sometime in the 90s. Thanks for going to the trouble to find references.

The effects were measured right before and after the speed limits were change, and cars did not magically get a lot safer at that exact same time. Thus, automobile safety seems to be an irrelevant variable in the quoted study.

Someone 5y ago
If cars, on average, last 20 years, 10% of cars get replaced in two years time. That can be significant. I also would think cars that get replaced are driven a lot more kilometers per year, so chances are a lot over 10% of all kilometers driven were in newer cars. ⇒ I’m not convinced increasing the speed limit didn’t make roads less safe. Reading https://www.cato.org/sites/cato.org/files/pubs/pdf/pa346.pdf https://www.cato.org/sites/cato.org/files/pubs/pdf/pa346.pdf, fatality rate dropped from about 1.7 to about 1.6. That’s about 6%. Eyeballing figure 1 in https://www.euro.who.int/__data/assets/pdf_file/0015/43314/E92789.pdf https://www.euro.who.int/__data/assets/pdf_file/0015/43314/E..., I see a drop that could be of similar size in the EU, too. ⇒ I’m not convinced increasing the speed limits made the roads less safe, either. In general, highways are about the safest roads, anyways, so you probably would have to look at safety only on those roads with higher speeds to be able to answer the question whether safety went up/down/nowhere.

mikestew 5y ago

There's a two year difference between measurements, as described in the quoted part of the above comment. Cars didn't change that much in those two years*, nor did everyone go out and buy new cars. * Airbags were already mandated in the U. S. at that point, and though I oddly can't find a reference, I believe anti-lock brakes were mandatory at that point, too.

saila 5y ago
Reading through this, it doesn't sound like ABS was required in 2009: https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/811182 https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/.... Another source says it's been required (federally) as of 2013: https://knowhow.napaonline.com/what-does-abs-mean-on-a-car/ https://knowhow.napaonline.com/what-does-abs-mean-on-a-car/.
- mikestew 5y ago
  Man, I could have sworn ABS became mandated standard sometime in the 90s. Thanks for going to the trouble to find references.