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Except that what's fatal is high relative, not absolute, speed.



It seems like a large claim to say that an accident between someone going 60 and 40mph is as fatal as an accident between someone going 60 and 80. I would need to see empirical evidence to consider the claim.

Absolute speed is one of the key values indicating how much energy is in a car crash.


Think of it this way: The relative speed between your car and a tree is whatever speed you’re going. 80 is more than 60.

But if everyone around you is going 80 and you’re going 50, you’re the tree. People going too slow on the freeway are dangerous. But not as dangerous as people going crazy fast.

The real problem is when people go slow in the fast lane. Or fast in the slow lane.


Head on and angle collisions cause the most vehicle-vehicle deaths.


My info may be outdated, but I thought the highest injury rates for vehicle-vehicle collisions was from getting T-boned by people running a red light. You have a stationary vehicle getting hit into its least protected part by a speeding vehicle. In older cars this sort of collision can be deadly at speeds as low as 30mph. Something about the two sides of your brain slamming together and lack of side crumple zones.

That’s why Slovenia (probably from an EU directive) made it illegal to run a yellow light in the early 2000’s. Yellow means stop unless you’re already in the intersection and can’t stop in time.

As opposed to USA where yellow, at least in practice, means “accelerate like mad”


Yellow could be used to start the sequence in reverse order. You are stopped at an intersection with a red light, light turns yellow for a brief time indicating proceed with caution as the cross street has just had its green light go directly to red. The brief yellow turns green allowing cautious transition of cross traffic right of way, instead of the regular use of yellow which seems to induce a lack of clarity on what to do, accelerate or decelerate. Green directly to red makes it very clear what to do, stop or maintain velocity. The grey zone still exists but it is on the new flow to proceed with caution instead of just, green=go. Rightly this would be rejected as it wacky, but wow t-boned accidents are horrendous and people really like to game the yellow light in a reckless way. How can we move towards caution.


In Europe lights go from red to red + yellow to green and from green to yellow to red. That’s how you know which yellow it is.

And at least in theory just yellow does mean “proceed with caution”. You have intersections without a green light, just flashing yellow.


I think t-bone would be under angle collisions.


Does Slovenia do “all-way” reds for a few seconds before anyone gets a green? That’s what USA/Canada does.


Bumping into a tree at 20mph is significantly less fatal than a 80mph person rear ending a 60mph person because in the latter example, the drivers lose control and just keep going at high speeds.


I don't think most accidents are cars driving into the backs of other cars?


I think it's quite a lot of them! But both vehicles are designed to absorb a lot of energy in this scenario.


people who study the traffic safety problem area will generally avoid saying the word "accident", just for your information.

https://www.grahamfeest.com/wp-content/uploads/2020/10/accid...


Such an over-long and redundant article. However, they do make a point (twice) that is no longer true:

>Only about 10% of accidents are caused by vehicle error, weather, or another non- human-related event.

Clearly the self-driving feature of more recently-made vehicles is going to, if not already doing so, cause more than 10% of crashes.


That's wrong. Relative speed differences result in collisions, yes. Absolute speed causes those collisions to be fatal. Low speed collisions are much less likely to be fatal.


what you did there, I see it.




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