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There is conflicting evidence on the matter. A local (Vancouver) video[1] circulating here had some strong arguments that our speed limits are kept needlessly

by tux1968 12y ago

There is conflicting evidence on the matter. A local (Vancouver) video[1] circulating here had some strong arguments that our speed limits are kept needlessly low. If you're interested in such things, it's a well done video and worth the 15 minutes it takes to watch. [1] http://www.vancitybuzz.com/2013/09/speed-does-not-kill-vancouver-roads/ http://www.vancitybuzz.com/2013/09/speed-does-not-kill-vanco...

elinchrome 12y ago
That video only gained traction in social media because it is telling people want they want to hear. It's always important to filter everything you read through "do I want to believe the thesis/conclusion of this?" Because a lot of people throw critical thinking out the window when they want to believe something.
- tux1968 12y ago
  That's not a refutation of the facts presented in the video though. There seem to be an equal number of people who support the status quo and don't want to look at facts that challenge what they want to hear. The facts should speak for themselves regardless of what each of us wants.
  - DanBC 12y ago
    > The facts should speak for themselves regardless of what each of us wants. But when I'm looking for facts I should prefer well constructed research, and not a documentary.
peatmoss 12y ago
Wrote my masters thesis in transportation planning on traffic calming. Peer review or it didn't happen. Not that peer review is perfect, but a viral video with an obvious agenda doesn't do it for me.
- tux1968 12y ago
  Heh, fair enough to be sure. However the video and the associated article that I linked do in fact reference multiple official studies. Examples: - http://www.fhwa.dot.gov/publications/research/safety/97084/97084.pdf http://www.fhwa.dot.gov/publications/research/safety/97084/9... - http://www.th.gov.bc.ca/publications/eng_publications/speed_review/Speed_Review_Report.pdf http://www.th.gov.bc.ca/publications/eng_publications/speed_...
  - peatmoss 12y ago
    Generally, worth taking government reports with a grain of salt. I've participated in a few, and the standards are often much lower than peer-reviewed articles. That said, on a quick skim, I don't see anything that strikes me as being obviously wrong / overturned (FHWA was 1997). But, I also don't see either source providing justification for driving faster. Both reports seem to accept this (in fact, this is about as close to pure physics you'll find in transportation engineering): From the FHWA's report: These requests are founded on public knowledge that crash severity increases with increasing vehicle speed, because in a collision, the amount of kinetic energy dissipated is proportional to the square of the velocity. Simply stated, when a vehicle is involved in a crash, the higher the vehicle speed, the greater the chance of being seriously injured or killed. and quoted by the BC report: A driver’s choice of speed can impose risks on other road users. Crash severity increases with increasing speeds because in a collision, the amount of kinetic energy dissipated is proportional to the square of the velocity. Now, beyond this, there are some subtleties. Both of these reports state that crashes are more likely to occur when there is a greater delta between fast and slow roadway users. That's fine. They also talk about how speed limits are more likely to be exceeded where the roadway design encourages higher speeds. Emphatically agree. So, now we are left with a policy question. Surely we agree that habituating people to breaking the law is bad. If people respond to a combination of law and roadway design (perhaps leaning more heavily on the latter), and we want behavior in line with law, what should we do? Ease the law or change the roadway design? Normatively, for most roadways (especially those containing bicycles and pedestrians), I say we need to move more toward changing the roadway design to discourage higher speeds. On some highways, it might be appropriate to lift speed limits, though even then I'd tend to cast a cautionary gaze toward the Montana experiment that was referenced elsewhere in this thread.
BrainInAJar 12y ago
Frankly the conclusions of that video are "cars are safer, so we can drive faster" which totally glosses over the fact that cars are safer and fatalities are down as a result. Raising the speed limit raises the fatality rate back up to 1950's level and that point just isn't made. Ultimately, how many deaths are acceptable for people to get to work 5 minutes earlier?

by tux1968 12y ago

elinchrome 12y ago

That video only gained traction in social media because it is telling people want they want to hear. It's always important to filter everything you read through "do I want to believe the thesis/conclusion of this?" Because a lot of people throw critical thinking out the window when they want to believe something.

tux1968 12y ago
That's not a refutation of the facts presented in the video though. There seem to be an equal number of people who support the status quo and don't want to look at facts that challenge what they want to hear. The facts should speak for themselves regardless of what each of us wants.
- DanBC 12y ago
  > The facts should speak for themselves regardless of what each of us wants. But when I'm looking for facts I should prefer well constructed research, and not a documentary.

peatmoss 12y ago

Wrote my masters thesis in transportation planning on traffic calming. Peer review or it didn't happen. Not that peer review is perfect, but a viral video with an obvious agenda doesn't do it for me.

tux1968 12y ago
Heh, fair enough to be sure. However the video and the associated article that I linked do in fact reference multiple official studies. Examples: - http://www.fhwa.dot.gov/publications/research/safety/97084/97084.pdf http://www.fhwa.dot.gov/publications/research/safety/97084/9... - http://www.th.gov.bc.ca/publications/eng_publications/speed_review/Speed_Review_Report.pdf http://www.th.gov.bc.ca/publications/eng_publications/speed_...
- peatmoss 12y ago
  Generally, worth taking government reports with a grain of salt. I've participated in a few, and the standards are often much lower than peer-reviewed articles. That said, on a quick skim, I don't see anything that strikes me as being obviously wrong / overturned (FHWA was 1997). But, I also don't see either source providing justification for driving faster. Both reports seem to accept this (in fact, this is about as close to pure physics you'll find in transportation engineering): From the FHWA's report: These requests are founded on public knowledge that crash severity increases with increasing vehicle speed, because in a collision, the amount of kinetic energy dissipated is proportional to the square of the velocity. Simply stated, when a vehicle is involved in a crash, the higher the vehicle speed, the greater the chance of being seriously injured or killed. and quoted by the BC report: A driver’s choice of speed can impose risks on other road users. Crash severity increases with increasing speeds because in a collision, the amount of kinetic energy dissipated is proportional to the square of the velocity. Now, beyond this, there are some subtleties. Both of these reports state that crashes are more likely to occur when there is a greater delta between fast and slow roadway users. That's fine. They also talk about how speed limits are more likely to be exceeded where the roadway design encourages higher speeds. Emphatically agree. So, now we are left with a policy question. Surely we agree that habituating people to breaking the law is bad. If people respond to a combination of law and roadway design (perhaps leaning more heavily on the latter), and we want behavior in line with law, what should we do? Ease the law or change the roadway design? Normatively, for most roadways (especially those containing bicycles and pedestrians), I say we need to move more toward changing the roadway design to discourage higher speeds. On some highways, it might be appropriate to lift speed limits, though even then I'd tend to cast a cautionary gaze toward the Montana experiment that was referenced elsewhere in this thread.

BrainInAJar 12y ago

Frankly the conclusions of that video are "cars are safer, so we can drive faster" which totally glosses over the fact that cars are safer and fatalities are down as a result. Raising the speed limit raises the fatality rate back up to 1950's level and that point just isn't made. Ultimately, how many deaths are acceptable for people to get to work 5 minutes earlier?