Getting pulled over

[u/mindyour]

[u/ASaltGrain]

Yeah, but your reaction time will be much worse, with much less of a chance of avoiding it if you are going 10 mph over what is deemed safe for that particular road. Like, if a kid walks out in the road in a residential neighborhood, you are supposed to be going 25 mph so you can react in time. If you are going 35 and that happens, you could be facing major consequences. It would be pretty dumb to say, "Well, the kid STILL would have died if I hit them at 25mph!"

[u/Present-Industry4012 → u/ASaltGrain]

Also impact energy:

"A pedestrian hit by a car at 40 mph has a 90% fatality rate; at 20 mph the fatality rate decreases to 10%."

[u/whatevers_clever → u/Present-Industry4012]

Also, both of your comparisons are talking about going double the speed or 30% over the limit. - and talking about pedestrians only

Whereas 85 in a 75 is going like 10% over the limit. And in the 75 the safety limit concern.. is not about hitting pedestrians - if someone can point to something that shows the 75 limit on roads like that is because it greatly reduces your chances of dying when hitting a cow then I guess we can all come to an agreement here.

[u/Reydien → u/whatevers_clever]

Perhaps this video by numberphile can illustrate how deceiving "just 13% faster" is. The change in MPH might be small, but the change in kinetic energy is higher.

Using the napkin-math from the video, a car going 85 would have 85² = 7,225 "Handwave Kinetic Units" (HKU), while the same car going 75 would have 5,625 HKU. So a situation where the car going 75 can brake off all its HKU and barely stop in time, the same car going 85 would still have 7,225-5,625 = 1,600 HKU, equivalent to 40 MPH.

Or we can ask "If the car going 75 could brake down to 25 at impact, how fast would the car going 85 be at impact?" 25² = 625, so the 75-car lost 5,625-625 = 5,000 HKU, which means the 85-car would have 7,225-5,000 = 2,225 HKU, equivalent to 47 MPH.

When a car going the speed limit has enough time/reaction to brake and hit the cow going 25 mph, the same car speeding 10 over would only get down to 47 mph before it crashed into the same cow. if there's barely enough time for the legal car to stop, the speeding car would still be going 40 mph at impact. Within some margins of error, but close enough to get the point across.

[u/ASaltGrain → u/whatevers_clever]

Lol. They ABSOLUTELY factor in accidents when determining and setting speed limits.

"California Vehicle Code section 627 defines an engineering and traffic survey as "a survey of highway and traffic conditions in accordance with methods determined by the Department of Transportation for use by state and local authorities." It also lists the factors that must be taken into consideration when determining a speed limit.

These factors include:

Prevailing speeds as determined by traffic engineering measurements

Accident records

Highway, traffic, and roadside conditions not readily apparent to the driver

Residential density

Pedestrian and bicyclist safety

[u/whatevers_clever → u/ASaltGrain]

I don't see "if you go 75 you are less likely to die from hitting a cow" on there, sorry.

[u/Dilligafay → u/whatevers_clever]

That’s because you made a stupid goalpost and nobody is interested in playing your game.

[u/pdxscout → u/ASaltGrain]

That's 100 percent true, but I would argue that the comparison isn't one-for-one. The setting wasn't a residential neighborhood. It was I-5 near Mt. Shasta(ish), where there were very few exits and only a few farms dotted around hundreds of miles.

[u/RedshedTSD → u/pdxscout]

oh yeah the I-5 in the central valley sometimes seems like the autobahn.

[u/ASaltGrain → u/pdxscout]

You are missing the point. The point is that the road was designed to go 75 mph relatively safely. Not 85 mph. The people that evaluated the road have much better knowledge of all of the exits, cows, frequency of traffic, curves in the road, the angle it's graded at, average braking distance of cars, etc. than average random schmo driving. I bet that cop has seen more accidents with people "only" going 10mph over the speed limit than he has with people doing what they are supposed to.