Driver stupefaction...

[Peter Ward]

In the latest NRMA open road comic that arrived in my letter box, I was bemused to read driver reaction times "in an emergeny" are apparently around. 1.5 to 3 seconds (!!!)

If these reaction times are true, then getting of the blocks for a 100 metre sprint (minimum 0.1 sec), returning a tennis ball (0.2-0.3 sec)...or just even stopping for a red light (amber lights depend on speed zone - 1 to 2 seconds typically) would challenge the bulk of the population.

Begging the question, why do motoring "authorities" pedal this rubbish?

And if true... why on earth would you let people drive, who take about 10x longer to react to an event than an individual with healthy senses....

[Miaplacidus (Brian)]

Is that with or without an iPod?

[RickS (Rick)]

Originally Posted by Peter Ward

In the latest NRMA open road comic that arrived in my letter box, I was bemused to read driver reaction times "in an emergeny" are apparently around. 1.5 to 3 seconds (!!!)

If these reaction times are true, then getting of the blocks for a 100 metre sprint (minimum 0.1 sec), returning a tennis ball (0.2-0.3 sec)...or just even stopping for a red light (amber lights depend on speed zone - 1 to 2 seconds typically) would challenge the bulk of the population.

These are all things that we practice and are trained to do. Once you've hit a tennis ball (that you're already expecting) a few thousand times it becomes instinctive. I'd guess that the 1.5 to 3 seconds time they are quoting is for dealing with a completely new and unexpected situation and that doesn't seem so surprising to me.

Cheers,
Rick.

[Poita (Peter)]

It is actually about right. Returning a tennis ball is not an emergency situation, you are watching and calculating trajectories and are placed and prepared and swinging well before the ball is anywhere near you.

Starting a sprint is also an event thoroughly expected and planned for i.e. you know exactly what to do when the gun goes off. Those reaction times average about 0.15 of a second for Olympic sprinters.

A car emergency is completely different. It is unexpected and could be any number of situations with a number of possible responses.

So you first have to
(a) Recognise that there is an emergency event
(b) Process the situation. Is it a dog or a kid, is that car parked or moving, do I have room to swerve or will braking stop me in time, is the road surface stable on the edge, is that a tree etc.
(c) Choose a reaction from the multitude of possible responses.

I used to race and was involved in training drivers. There is a big difference in reaction time on the skid pan to an expected event to an unexpected one, and those published reaction times fit with what we use to see.

Monash Uni has a paper on it that is an interesting read and explains a lot.
http://www.monash.edu.au/miri/resear...ther/hfr12.pdf
The data starts on page 26, but the whole thing is a worthwhile read.

Try this experiment for reaction time in a totally expected and simple event

www.brainmac.co.uk/rulerdrop.htm

[DavidTrap (David)]

I can see where you're coming from Peter, but I have to agree with the earlier responders as well.

Is there anything from the aviation literature about time between a critical event being triggered in a simulator and a pilot assessing the situation and initiating a response?

I know of some research done on cardiopulmonary bypass machines and they had a fancy camera that tracked where you were looking - the variations in how people looked at all of their monitors before/while responding to a situation were very interesting.

DT

[Poita (Peter)]

There is a ton of data on pilot response time to everything from visual or instrument based information, to air traffic controller response results.



Interesting are the ones where they have to process an urgent but complex response
http://ntrs.nasa.gov/archive/nasa/ca...2010036916.pdf


Sorry, the above is a different thing, but is a good read.

The Monash report in my previous post pretty much answers response time questions in a variety of situations, and it fits well with the NRMA article.

Originally Posted by DavidTrap

I can see where you're coming from Peter, but I have to agree with the earlier responders as well.

Is there anything from the aviation literature about time between a critical event being triggered in a simulator and a pilot assessing the situation and initiating a response?

I know of some research done on cardiopulmonary bypass machines and they had a fancy camera that tracked where you were looking - the variations in how people looked at all of their monitors before/while responding to a situation were very interesting.

DT

[Sarge (Rod)]

Peter,

I work in Road Safety and have done so for near on 40 years. It is true, driver reaction times vary from 1.5 sec to 3 secs. It is from the time the eye sees, to the brain analysing and the foot reacting. F1 drivers can get this down to less that 0.5 sec, but they are the exception. Drag car drivers can get it down to 0.1, but that is with anticipation of a start.
Road safety has been promoting the 2 sec drop back rule for a long time. Simply, as the car in front you passes an object there should be a 2 sec gap till you pass the same object - regardless of speed.
We all need to drive safely on our roads.

Clear skies

Rod

[Peter Ward]

It's interesting to note in the Monash paper, cited earlier, Sivak et.al determined reaction times in the order of *0.5 to 0.7 seconds*.... a figure I'd say was reasonable for someone actually paying attention to the road ahead.

.... many human activities would be impossible or extremely hazardous if you didn't have a level of anticipation to events about to unfold.

Improving road safety based on the lowest common denominator (eg 3 second reaction times) I'd argue is flawed.

I rather like the German model...a vastly higher standard of driver training and testing to ensure license holders are way more competent than our system of being trained by pottering around with Mum or Dad at 50km/hr.
Do a hill-start, reverse park and you're licensed...

[Peter Ward]

Originally Posted by Poita

It is actually about right. Returning a tennis ball is not an emergency situation, you are watching and calculating trajectories and are placed and prepared and swinging well before the ball is anywhere near you.

Ahh... can I respectfully suggest "you are watching and calculating trajectories and are placed and prepared" is exactly how you should be driving a vehicle?

[FlashDrive (Poppy)]

Originally Posted by Miaplacidus

Is that with or without an iPod?

Good one I'll pay that ..! and I'd like some ' fries ' with that to ...

[Poita (Peter)]

Originally Posted by Peter Ward

Ahh... can I respectfully suggest "you are watching and calculating trajectories and are placed and prepared" is exactly how you should be driving a vehicle?

It is possible that you are missing the point here a bit.

I agree that is how people drive when concentrating, you know the speed and weighting of the vehicle, you anticipate the upcoming corner etc. but an emergency situation is completely different and reaction times are much longer, even with professional drivers on a test track.

Even when well prepared and concentrating, an emergency situation is very different to an expected scenario, and you can't pre-empt every possibility.

We tested and trained rally drivers and road circuit drivers, and for a predictable situation (light change, expected turn etc.) then the reaction time is often less than a second.
For *emergency* situations, i.e. unpredicted events, then the reaction time is around 1.5 to 3s or longer. There is so many more variables both on the input and output side, plus the 'shock' factor of an unexpected event, i.e. your brain has to deal with the unexpected and categorise and recognise it first, it takes up some CPU cycles, as does deciding the course of action and then getting the signals to the muscles in question.

It isn't a straightforward reaction chain in an emergency, unless it is one you have been in many times and can recognise and process it instantly, and were somewhat expecting it to happen.

[Poita (Peter)]

Originally Posted by Peter Ward

It's interesting to note in the Monash paper, cited earlier, Sivak et.al determined reaction times in the order of *0.5 to 0.7 seconds*.... a figure I'd say was reasonable for someone actually paying attention to the road ahead.

.... many human activities would be impossible or extremely hazardous if you didn't have a level of anticipation to events about to unfold.

Improving road safety based on the lowest common denominator (eg 3 second reaction times) I'd argue is flawed.

I rather like the German model...a vastly higher standard of driver training and testing to ensure license holders are way more competent than our system of being trained by pottering around with Mum or Dad at 50km/hr.
Do a hill-start, reverse park and you're licensed...

Sure, better driver training is a good thing, (Germany still had 4,500 road fatalities in 2008 though) but designing road systems and safety around the best case scenarios assuming that all drivers will have the best reaction times possible is idealistic and would lead to a serious increase in accidents.
Even the best, most switched on drivers can have a moment of less than pure concentration, you want to have some pretty solid leeway built in when it is lives on the line.



The Sivak paper I read shows 72% of test subjects taking under 3s to react to a brake light of the car in front of them, which again fits the NRMA data.

[AstralTraveller (David)]

I notice when watching cricket they will show the time between the ball hitting the bat and the fielder taking that screaming catch at slip or the time between the ball release by the bowler and the batsman playing a shot, and I notice the time is consistently close to 0.6s. It seems an elite athlete, fully focussed can react to a more-or-less predictable event in that time. I also notice that they can't maintain such focus throughout a 6 hour day. Part of the skill of a batsman or fielder is to relax between deliveries. In fact in 6 hours they are probably only at full concentration for 1-1.5hrs. A driver doesn't have that luxury.

I also remember from my younger, somewhat lead-footed days that driving a road at (say) 100km/h might have been easy but going 110 took a lot more concentration (especially in an FC holden ) and I became tired sooner. So even a conscientious driver needs to understand that they will not be operating at max effort all the time they are on the road. As for the 'I couldn't give a rats' crowd, they are probably never above 50% efficiency.

I'm very conscious of leaving enough braking distance (30 years in a troopie will do that to you) and am constantly horrified by how little room most people leave themselves. I've tried timing how far I am behind the car in front (count 'and 1 and 2') and 2 seconds is further than you think and much further than most drivers ever leave themselves. My theory is that if I leave enough room I can afford to relax a bit, look at the scenery a bit be safer and arrive in better condition.

[Terry B]

Originally Posted by Peter Ward

Ahh... can I respectfully suggest "you are watching and calculating trajectories and are placed and prepared" is exactly how you should be driving a vehicle?

Peter
How long can you maintain a high level of anticipation for whilst driving?
I'm sure I can do it for an hour or so but how about on a 6 hour drive. Even with regular stops it is not easy to maintain the high level of responsiveness needed to react to an emergency within 0.7sec

[ZeroID (Brent)]

Hmmm, interesting... Rally driving is all about reaction to unexpected driving obstacles and situations. Yes, the Co calls the next corner, known hazard, etc but very often it is the unexpected that is the decider. Deer, cow on road, dislodged rock from previous car, stopped competitor, new mud, slippery surface. I daresay Seb Loeb (and a lot of other top drivers) would be in big trouble if their reaction time to the unexpected at well over 100+ kph was 1.5 to 3 seconds.
My information said .5 to .7 for mental reaction to action was the norm. I have driven Rally cars and track events.

I confess I do drive much more 'actively' than most road users and am more aware than most as to road conditions and situations. Both our cars are slightly civilised rally cars, VR4s with turbos, 4WD, AYC, ceramic brakes and over 300 hp. I do take advantage of the capabilities sometimes.

[Poita (Peter)]

Even in Rally drivers testing has shown the average response to be 1.5s or so, and that is with you basically expecting something to pop up in front of you the whole time.

The 0.5 to 0.7 seconds is really a totally best case scenario, the travel time for the nerve response alone from brain to foot in a 180cm male eats up a reasonable portion of that.



0.5s response times can be readily achieved, but not maintained, even during a controlled event like a race.

On the open road on a long trip with all of the other things on your mind, an average of 1.5 - 3.0s is a pretty reasonable expectation.

[Peter Ward]

Originally Posted by Poita

The Sivak paper I read shows 72% of test subjects taking under 3s to react to a brake light of the car in front of them, which again fits the NRMA data.

The Monash paper states Sivak found:

"The distance separating the lead and experimental vehicles had a highly significant effect on the braking reactions in the Sivak et al (1981b) study. For the short following distance, the mean reaction times for the various configurations ranged from 550 ms to 700 ms, and for the long following distance condition, the mean values lay between 670 ms to 830 ms"

Problem with a lot of this stuff is, lies and statistics. Sure the Germans have a significant number of road deaths, but the rate per capita is significantly lower than Oz. The autobahn rate is even lower still... guess they are *really* paying attention at 200 klicks.

[Octane (Humayun)]

All those reaction times can go out the window if you aren't well-rested, too.

I saw a documentary on sleep deprivation. They put a guy who hadn't slept for 2 days in a car and tested his reaction skills. He failed pretty much every single one. One of the tests/obstacles was was throwing a doll (about the size of a five year old child) onto the course. Someone who was alert was able to brake and swerve and miss the doll. The drivers who had no sleep for 1 or 2 days hit the doll before reacting, or didn't even know they hit the doll and didn't react at all.

H

[Baddad (Marty)]

One of my pet subjects. Safe Driving.

I used to cycle 5 klms each way to school. I saw many accidents involving cyclists and cars. I was involved in a minor one.

As I saw it, motorists seemed to be blind for cyclists. When I was hit, the women apologetically said, "I just didn't see you until I hit you."

How could she not have seen me? I was right in front of her. She had not waited for the intersection to clear. I did not believe what I saw. She stopped and then proceeded to go through the intersection. Hit the brakes just before she careered into me.

I believe she had seen me but it did not register. She only had partial attention to her driving. Only looking for cars to clear. This is how many people drive. Partial attention and then react so slowly when quick responses are required.

Another story: I was about to enter a main road (I was driving a car).
I noticed a young waman tailgating. It was a few minutes before I joined the flow of traffic. Eventually I came upon the woman's car I saw earlier. She had rear-ended the car in front of her.

I stopped to help. The young lady was abusing the driver in front of her. "He should not stop so fast. Drivers behind you need time to stop."

She further claimed that he was in the wrong and that he is responsible for the damage to her car. (WOW. This girl needs to be licence retested)

The driver in the front car stated that he slowed normally indicating a right turn and stopped waiting for clearance. Witnesses confirmed that.
Again, inattention and driving beyond her means. Tailgating and slow to react.

Even paying the due attention to driving, at 60K/H you travel 12M in 0.7 secs. That is before you even start to slow down.
With out due care, 2 secs puts the car through the intersection, 35M

Idealy I would have liked to see all young drivers do one year on bicycles before being awarded a full licence. It makes you more aware of safety and promotes a defensive attitude. Of-course that is not practicable in the real world.

However I rarely have a close call. The only accidents I have been involved in in the last 20 years have happened while I was stationary at intersections or as a passenger. Where I had no control.

I can quite believe that 2 -3 secs reaction time to be common place. It therefore means we adopt the attitude that all other drivers are half asleep at the wheel and drive accordingly.

Cheers

[Peter Ward]

Originally Posted by Terry B

Peter
How long can you maintain a high level of anticipation for whilst driving?
I'm sure I can do it for an hour or so but how about on a 6 hour drive. Even with regular stops it is not easy to maintain the high level of responsiveness needed to react to an emergency within 0.7sec

Don't know. I drive very defensively...keeping away from traffic clusters, and for example, never assume just because a light is green, someone isn't trying to T-bone me.

I always try to be *very* predictable, e.g. indicate before I brake. Make sure my cars are very well maintained.

I suspect this is a legacy from being a motorcycle rider in my youth. Don't quite know what my reaction times are, but I do "create time" by keeping safe gap & look far beyond the car infront/behind etc.
Works for me....well almost...got rear-ended about 8 years ago..P-plater not conversant with aquaplaning.