Crashes increase when speed limits dip far below engineering recommendation

[aussiblue]

https://www.sciencedaily.com/release...1212135021.htm

Speed limits set only five miles per hour below engineering recommendations produce a statistically significant decrease in total, fatal and injury crashes, and property-damage-only crashes, according to a group of Penn State researchers.

"If (however) you lower the speed limit by 10, 15, 25 miles per hour, or more, drivers stop paying attention," said Vikash Gayah, assistant professor of civil engineering. "We found there was an increase in fatal and injury crashes at locations with posted speed limits set 10 miles per hour or more below engineering recommendations."

Speed limits are normally set based on results from engineering studies that collect free-flow traffic data and then select an appropriate speed using a statistical model. However, factors such as school zones, citizen or political pressure, and perceived safety issues contribute to the fairly common practice of lowering speed limits below engineering guidelines, the researchers report in Accident Analysis and Prevention.

[GasoLane]

I used to work on the theory that if you drive fast enough you're past the crash before it happens

[simon varley]

I bet MUARC could take the same raw data and come to a completely opposite conclusion.

[Silver Ghia]

Originally Posted by simon varley

I bet MUARC could take the same raw data and come to a completely opposite conclusion.

Most likely due to where their funding comes from.

[LG17]

The possibility of crashes increases when the moron on the phone in front of you is doing 75kmh in a 100kmh zone with very few passing opportunities!

[Bossxr8]

But, but, but speed kills.

Not as much as inattention does, but inattention cameras don't exist.... Yet.

[Trendseeker]

Originally Posted by Bossxr8

But, but, but speed kills.

Not as much as inattention does, but inattention cameras don't exist.... Yet.

They’re coming.

https://www.smh.com.au/politics/nsw/...16-p50mjd.html

[arronm]

Try riding a motorbike with all these car users on the phone. Its hit or miss whether you get to you destination.

[mike_nofx]

Originally Posted by arronm

Try riding a motorbike with all these car users on the phone. Its hit or miss whether you get to you destination.

Part of the thrill of riding a motorbike is knowing you have a much much higher chance of death in a minor accident than you do in a car.

If that thrill isn’t high enough, ride a bicycle alongside cars doing 100km/h whilst wearing your little sisters tights.

[arronm]

Originally Posted by mike_nofx

Part of the thrill of riding a motorbike is knowing you have a much much higher chance of death in a minor accident than you do in a car.

If that thrill isn’t high enough, ride a bicycle alongside cars doing 100km/h whilst wearing your little sisters tights.

That is a ridiculous comment.

[happy1]

I saw something about lowering the general speed limit all across WA with 10km. I'm not sure if that will fix the fatal accident statistics.

I think the road design needs to have soft shoulders (not large trees etc.), and there should be invested in more physical barriers between the lanes in opposite direction. This will mean more 3-lane roads with overtaking possibility alternating approx. every 5 km.

Cheers,

[ebv8]

alot of people will disagree with me but i find if i'm doing say 5-10km/h under the limit i forget my trip when i have got to me destination, if i ride the limit i tend to enjoy the drive and remember the whole trip, in my mind that means i was paying more attention to the road and my surroundings so i see the merit in higher speed limits

i ride also and the 2 types to watch out for in my area are the a-b drivers and the junky hoons, (oh and 4x4 drivers with front window stickers and roof mounted light bars)

[Trevor 57]

Crashes increase when speed limits dip far below engineering recommendation when idiots behind the wheel do stupid ****

[jpd80]

In a way, automatic transmissions are enabling lots of people to be distracted by their mobile phones
Going back to clutch and manual transmissions would stop a lot of people using phones while driving.

[mike_nofx]

Originally Posted by jpd80

In a way, automatic transmissions are enabling lots of people to be distracted by their mobile phones
Going back to clutch and manual transmissions would stop a lot of people using phones while driving.

I think the type of people who will play with their phone while driving will do so regardless of manual or auto. So it’s possible the manual may just create an extra hazard.

[DJR-351]

Originally Posted by mike_nofx

I think the type of people who will play with their phone while driving will do so regardless of manual or auto. So it’s possible the manual may just create an extra hazard.

Cars stalling everywhere

[knight rider]

The sense of speed and your attention is only higher when your driving faster than everyone else, if your doing 100 and everyone else is doing 80 you feel like you are flying, and if everyone and including you are doing 120 it feels slow and you lose focus on what your doing.

So the answer is drive faster than everyone else FTW

[roddy1960]

Bears no real correlation to this thread but when you talk low speeds , crashes etc this makes me chuckle .. How many of us come across this , especially as we head into the summer hols on our way to the coast or to work or something .. Frustration taken to a new level sometimes ..

https://www.youtube.com/watch?v=O9f0QOh5KAU ... and another driving one from the one and only John Williamson

https://www.youtube.com/watch?v=rLRY-2CVHM0 ... Funny stuff ..

[Franco Cozzo]

Originally Posted by jpd80

In a way, automatic transmissions are enabling lots of people to be distracted by their mobile phones
Going back to clutch and manual transmissions would stop a lot of people using phones while driving.

Nah, I'm pretty good at looking at porn on twitter while driving my manual car through gridlocked Melbourne.

I live in the regional outskirts of Melbourne, we've got a road thats about 30km long that joins us to outer Melbourne, its a single lane country highway, speed limit 100km/h - its a 'black spot' because of a huge amount of lethal accidents, there is no problem with the road, just that this happens:



Some douche will play pretend policeman and then you end up with a heap of cars bunched up doing 70-80km/h and if you want to overtake you need to chop 6-10 cars in one hit, there is only 4 or so spots in 30km that are safe to overtake.

There are two overtaking lanes, but what happens is someone will overtake the guy doing 80km/h at 85km/h and blocks everyone behind, or the guy doing the 80km/h suddenly finds the accelerator goes in more and goes up to 110km/h but then drops back to 80km/h when the overtaking lane is gone

Easy solution - more consideration, move left for faster moving traffic, problem solved.

[Silver Ghia]

Originally Posted by Franco Cozzo

....

There are two overtaking lanes, but what happens is someone will overtake the guy doing 80km/h at 85km/h and blocks everyone behind, or the guy doing the 80km/h suddenly finds the accelerator goes in more and goes up to 110km/h but then drops back to 80km/h when the overtaking lane is gone

Easy solution - more consideration, move left for faster moving traffic, problem solved.

Looks like I'm not the only one who finds that problem along that road.

I estimate around 90% of the slow drivers do that. No exaggeration.

Then there are the ones who accelerate when they see someone pulling out to pass them on the normal two way sections.

[vztrt]

Originally Posted by Silver Ghia

Looks like I'm not the only one who finds that problem along that road.

I estimate around 90% of the slow drivers do that. No exaggeration.

Then there are the ones who accelerate when they see someone pulling out to pass them on the normal two way sections.

Funny enough you don't find this issue when you have a car with engine performance.

[Franco Cozzo]

Originally Posted by vztrt

Funny enough you don't find this issue when you have a car with engine performance.

It's not a matter of what you got under the hood, the problem in the above photo is I can't see what's coming the other direction to try chop a group of bunched up cars.

The speed up thing is rediculous I've been in situations where we've been doing 80 then for some reason we're doing 120km/h for the duration of the overtaking lanes then back down to 80?

[Silver Ghia]

Originally Posted by vztrt

Funny enough you don't find this issue when you have a car with engine performance.

Being in the Victorian state where the emphasis is on speeding drivers going only 3kph over, and that that road is frequently patrolled, its wise not to use that performance unnecessarily. But when you suddenly find yourself having to do 120 or so to complete the overtake when only doing 80 or 85 before...

[M&Ms]

All state government's, hwy patrol's and do-gooders have blood on their hands with every fatality and injury that occurs on our roads. Speed limits at an all time low, speeding tolerance at an all time low, speed cameras and enforcement at an all time high, speeding revenue at an all time high, car safety at an all time high; yet the road toll is woeful.

I will bet my pet pug that if all speed limits were increased by 10 km/h for 10-80 zones, and increased by 20 km/h for current 90-130 zones, and an official tolerance nationwide was made known that "up to 10 km/h above the speed limit is not an offence," we will see a reduction in fatalities, injuries and road rage incidents.

Shame we don't have any federal governments with enough balls to take ownership of road rules nationally and implement a more reasonable approach (and while they're at it, just get rid of state governments altogether, will solve a multitude of other problems this country has).

[Fed]

There's only 4.5 Minutes difference between doing 80KPH & 100KPH over 30 Km distance, what's the rush?

[M&Ms]

Originally Posted by Fed

There's only 4.5 Minutes difference between doing 80KPH & 100KPH over 30 Km distance, what's the rush?

Well that 4.5 mins is 9 mins on a return journey, which is 45 mins over a 5 day working week.

Problem is this is a vast country, and distances at times far exceed your 30km quote. Some may travel 120km between destinations each day, all of a sudden your 4.5 minute quote becomes 18 mins or 36 mins on a daily return, which is 3 additional hours per week on the road!

Now, on the flip side, if the speed was 120 instead of 100, you'd shave 3 minutes from said trip, or 7.5 mins from your 80 km/h limit for a 30km trip, which is 75 mins per week less on the road for a 30km trek, or a whopping 5 hours per week less on the road! Now calculate that over the course of a year.

Time not spent on the road is time not spent on the road! Car's are safer, tyres are better, braking is better. The highway speed limit was set based on the distance it took a car in the 1970's to pull up from 70 MPH - that distance on average for a modern car is now halved, meaning limits should theoretically be increased 20 or 30 percent!

The amount of people brainwashed by our inept, broke, desperate state governments who try leach driver's of every cent they can is mind boggling.

[xxx000]

Originally Posted by M&Ms

…... The highway speed limit was set based on the distance it took a car in the 1970's to pull up from 70 MPH - that distance on average for a modern car is now halved, meaning limits should theoretically be increased 20 or 30 percent!.....

Can you please provide proof of your above statement re how speed limits were set in the 1970's?
A link to a credible source will suffice

[Citroënbender]

My father was part of setting the speed limits on some sections of NSW roads forty years ago. I remember tales of ad-hoc limit setting; the road engineers would have a fang, the coppers would have a bat, then they’d try to butt heads and agree on a limit that was safe/reasonable. And before then, in the golden age of freeway planning, a notion that the roads being penned, would one day enable drivers to travel safely at 100MPH.

[Franco Cozzo]

Originally Posted by Fed

There's only 4.5 Minutes difference between doing 80KPH & 100KPH over 30 Km distance, what's the rush?

4.5 minutes makes the difference between getting to work on time or late

I use my phone and drive all the time - speed limits are so low and traffic that bad when you get into Melbourne that it's a minor risk.

Seems to be a very Melbourne centric thing, caught up with my Adelaide counterparts at their branch and one was saying he couldn't believe how openly people use their phones driving around Melbourne, no one hides it, everyone does it.

With speed limits I'm generally doing speed limit + 20km/h as it's just a few points and a few hundred bucks

So if it's the Tullamarine Freeway I'm doing 120 in the 100 sections, 100 in the 80 sections and if it's the 110 limit on the Calder I do 128km/h because of recent changes in VIC

[ebv8]

i was driving on an old section of the princes hwy thats getting re-done
the old road was hilly, winding, narrow, single lane undivided with short overtaking lanes with blind corners and the speed limit was 100km/h, its 80 now due to construction zones but all do 90 anyway
the new road is dual lane, divided, flat and straight and the speed limit will be 100kmh
cars are safer and handle better and the road is 100% better but the same speed limit
i don't get it
spend more educating drivers i think