Aug 04 2011
The Mind is Faster than the Foot
You’re driving down the road when the car in front of you suddenly slams on the breaks. You see their break lights go on followed by the car rapidly getting closer to you and filling your visual field. Your brain registers what is happening and immediately plans a motor response in reaction – take your foot off the gas and apply pressure to the brake. Your car then screeches to a halt – but will it stop quickly enough to avoid colliding with the car in front of you?
A recent study looks at the ability to predict when a driver is about to brake in an emergency breaking situation. They used a driving simulator and monitored the gas pedal, the brake, the muscle activity in the subjects’ legs (EMG), the speed of the car, the distance to the car in front, and the EEG activity (electrical brain activity) of the driver. What they found is not surprising, but quantifies the time intervals involved.
The EEG reveals that the visual stimulus is recognized first, followed by the intention to perform a motor action (240 ms – miliseconds). Then the motor action begins (335 ms), resulting in stopping the gas (430 ms) and then applying pressure to the brake (595 ms). There is actually a range of figures for each event, based upon the accuracy of prediction. The longer you wait, and the more data you gather, the higher the accuracy. Predictive accuracy of >95% was generally achievable using information from EMG and EEG. To boil it all down, the authors estimate that a system using EMG and EEG can predict a driver’s intention to brake in an emergency setting 130 ms prior to when they would actually brake. This potentially could result in a 3.66 meter shorter breaking distance, which can mean the difference between a crash and near miss in many cases.
The researchers demonstrate that there is a window for improved reaction time in emergency breaking (130 ms) and that window is large enough to make a practical difference is crash avoidance. They further speculate that a driving assistance system based upon this information could therefore reduce car crashes.
A major limitation of the system, of course, is that the driver would have to be fitted with EMG and EEG leads while driving. This is a non-trivial limitation – who wants to wear a cap full of electrodes while they’re driving? The technology to measure brain waves accurately without such leads is not available or even on the drawing board.
Such as application also assumes that we can engineer a computer system that would respond faster than the driver themselves with sufficient accuracy that it will not cause more accidents than it prevents (by, for example, registering a false positive and applying the brakes).
Another option for achieving the same goal is to take the driver out of the loop – with collision avoidance systems. These are already in use. Essentially sensors on the car detect the rapidly approaching obstacle and apply the brakes themselves.
This research, however, does highlight a couple of interesting points. The first is that, in an emergency breaking situation, miliseconds make a difference. Further, the time it takes for the driver to realize that they need to break is significant. There is a certain minimal amount of time necessary for the brain to process the sensory information and plan an action. This cannot be avoided, and is precisely why you should not tailgate. However – this assumes that the driver is paying attention and is prepared for the possibility that they will have to urgently brake. If the driver is distracted, even a little – by, say, talking on a cell phone – that will add precious miliseconds to the overall reaction time and significantly increase the risk of accident.
I don’t think we’ll be driving around wearing an EEG cap anytime soon (if ever), but there are ongoing efforts to add passive accident prevention to cars to make them safer. Human drivers are slow to react (compared to the fast speeds at which we often drive), are easily distracted, cannot multitask, and have a hard time maintaining continuous attention. Computers, however, have none of these failings. They are tireless and focused. They are not as smart as humans, but if given a very specific task we can develop the programming to assist or even take over some simple functions, like very quickly applying the brakes to avoid a head on collision.
22 Responses to “The Mind is Faster than the Foot”
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Do we have any statistics on what the leading causes are for people breaking suddenly? Animals, humans or other cars?
Prevention could also be employed using computers. Throttling sudden acceleration and speeding in built up areas for example. You just need a reliable GPS with speed limit data. Warning about your nearness to the car in front could also be added for more than just parking. Fully functional technologies today.
It seem to me that you could save 150ms with a technical redesign of acceleration and breaking in cars. One in which removing your foot from the gas pedal is equivalent to breaking. Or better yet, remove all the controls from the inside of the car and replace them with a USB port and a playstation controller. I bet that would boost reaction times.
Those times seem kind of fast. I wonder under what conditions the tests were performed? (Don’t want to register to download the study.) If the test subjects were primed and ready to brake, the time-to-react would be much faster than in the real world where the driver was not expecting to brake.
eiskrystal=”Do we have any statistics on what the leading causes are for people breaking suddenly?”
My anecdotal experience,is that tailgating in and of itself,leads to sudden braking. When you get a series of cars following too closely,the lead car merely slowing down normally,for say,a traffic backup,can cause a cascading effect that makes each subsequent vehicle have to brake increasingly harder.Sometimes this leads to collisions,or destabilization and chaos in the traffic flow.
I would like to see brake light systems designed to respond dynamically to brake pedal pressure in such a way, that the lights would begin to flash when more than normal pressure is applied,and will flash faster with greater pressure,in an effort to ‘wake up’ the people following to a potential collision.
I’m actually surprised, now i think about it, why we still drive with pedals anyway. A small well-designed hand controller “would” be a lot faster and more comfortable than kicking different things with your legs. You could then get rid of half the stuff in front of the driver and save some weight and space.
“I’m actually surprised, now i think about it, why we still drive with pedals anyway. A small well-designed hand controller “would” be a lot faster and more comfortable than kicking different things with your legs.”
A controller doesn’t achieve the resolution and feedback one needs for driving a car. The analog response of a gas-pedal and steering wheel is much more accurate than a hand controller. Also if you have ever played grand theft auto or a similar game, you know it’s not easy to drive normally with a controller. Because the risks of bad driving are much lower in a video game, you tend to inappropriately transfer these low risks to a real life scenario.
So although I am good at using game controllers, given the option, I would take a traditional steering wheel / pedal design.
There are hand operated controls for cars available. They allow paraplegics the ability to drive. I don’t see why it would be illegal to use them if you are able bodied. Mercedes once produced a video game style controlled concept car.
Computerized sensors that brake for the drivers sound great for new cars. I’ve been hit several times by drivers that see the situation, shout or yell instead and don’t engage the braking system. Yet other drivers took the precautions to stop. Maybe this is just road rage or fear to take action?
PhysiPhile do we have any research into that? I wouldn;t even know where to start looking.
I wonder if that would mean that people on bikes are even more accurate since when i’m riding it does sometimes feel like the bike is part of me.
I do wonder how much of what you say is comfort with the familiar though. I mean obviously the control would have to be responsive with instant feedback and i doubt the final controller would be similar really to a game controller.
I’m thinking that something like this could be used as an added failsafe in situations where commercial practicality doesn’t apply and false negatives-be-damned. Imagine a delicate operation involving large machinery or robotics. Maybe this sort of brain scanner could pick up the “OH S***” signal from the brain and freeze the operation a half a second faster than it would take the operator to hit the kill switch.
The utility of these studies may not be in having a computer recognize the user intention but in having data where it is always safe to override the pilot.
If the car computer knows a collision is inevitable because the pilot was too late to react, but still time for some automated safety system, then it can override the pilot and fully break the car to avoid it.
Before studies like this they had no data to know when they could start, because humans don’t like that a computer takes his place when they are still in control.
Note that there is no chance of false positives, unless the math is wrong (software bugs) or bad sensors (nothing that redundant systems couldn’t solve).
The most dangerous hazard on a road is typically the distracted driver, whose reaction times are slow at best. But we see from this study that even under controlled circumstances where drivers know they will be expected to brake, computer assisted response seems to offer a significant improvement over flesh and bone driver input. I’m not too surprised. Wire me up.
As to the use of thumbstick or D-Pad controllers to guide a car, they’re certainly not ideal. As a long time enthusiast of sim-racing, I can tell you that the smooth application of gas, brake and steering inputs is crucial to controlling a car, and these are all improved with a wheel and pedals over a hand held controller. Wheels and pedals also provide a detailed level of feedback to the driver that a thumb stick can not do without sacrificing control.
That said, if someone wants me to test drive a Ferrari with an X-BOX controller, I’d give it a shot… for science.
tmac57′s idea of somehow using the brake lights to signal how hard the driver in front of one is braking sounds like a winner.
Steve, please fix the use of “break” for “brake”. It is driving me crazy.
min,
Bloggers’ number one rule is that typo corrections will be ignored as irrelevent. They are posting on the run, not writing a book.
I don’t think Steve is about to brake that rule.
eiskrystal: “Warning about your nearness to the car in front could also be added for more than just parking.”
I’d agree with that. A front-of-pipe solution seems most practical.
People should have the option of turning off a visual or audible alert telling them they were driving too close to the car in front, but there should also be a penalty for someone who chose to drive without it and then crashed because of that choice.
“PhysiPhile do we have any research into that? I wouldn;t even know where to start looking.”
I was thinking more about the travel distance of a button or joystick on a controller versus a gas pedal. The greater the travel distance the higher the resolution you have on how much throttle you give. So using a controller would feel like a new teenage driver who jabs the gas pedal instead of slowly pressing it down.
I just don’t see any advantage of using a controller besides it takes a little less brain and muscle power. But this is such a small difference that I couldn’t justify even a minuscule risk of crashing.
“I wonder if that would mean that people on bikes are even more accurate since when i’m riding it does sometimes feel like the bike is part of me.”
Yeah, I think so. I think a reasonable hypothesis would be: the more control you have over an object the more your brain integrates that object into its body map.
tmac57,
This is already in the works. The idea being that the current brake light setup only say’s the brakes are being applied, but makes no distinction on how hard the brakes are being applied. Not that long ago I read articles about a group that was toying with this. If I remember correctly, they were going to use a line of lights (can’t remember if it was on both sides of the car, or a single “bar” in the middle) and when the brakes were softly applied, only the middle would light and the more the brake was applied the longer the light bar would get from the center. I haven’t heard anything more about it, so I honestly have no idea how the testing went, or if it was ever carried out…but the idea is at least being kicked around. Also, clearly it is important to focus on the vehicle directly in front of you, but when it’s possible you should always keep an eye on the vehicle(s) in front of that car (with your peripheral). Paying attention to what the cars in front of the one that is directly in front of you can give you valuable info and can, in a way, “predict” what the car in front of you will do before it does it. When possible I usually focus on the area of the tail lights of the vehicle that is two ahead of me (through the glass of the car directly in front of me). This generally allows me to keep an eye on what both vehicles are doing. There have already been several instances where I was “saved” by catching something a vehicle was doing two or three ahead of me, that the one directly in front of me missed because of being distracted. I would also like to see some progress made in avoiding animal collisions. I have never seen data on how well those “deer whistles” work, but my guess is not very well.
Here are a couple pertinent links….
http://www.daimler.com/dccom/0-5-1210220-1-1210701-1-0-0-1210338-0-0-135-7165-0-0-0-0-0-0-0.html
http://www.physorg.com/news93882626.html
chaos4zap- Hey,thanks for the links.I guess that I wasn’t the only one that thought this might be a good idea. This is something that I have been thinking about for 20 years or so.
I also had thought about a sensor that would detect a vehicle following too close for the speed conditions,and flash your tail lights to warn them,but knowing human nature,and that there are some real assholes on the road,I bet that some people would intentionally trigger that feature by tailgating you for fun,or to intimidate you into moving out of their way,so I’m not sure if it would have the desired effect or not.
Yeah, I would imagine that there are few times when someone is tailgating and they are not already aware that they are, so I doubt that a flash of your tail light would get them to back off. Those times when they are not aware they are following too closely, the technology is best served in the trailing car (I’m sure you are aware this technology already exists) I was a safety manager for a transportation company for a number of years and as far as I’m concerned, the two largest area for improvement are preventing animal (or people) strikes and technology that can detect when the driver is dozing off. The obvious end-game is to all but eliminate the human (and the human factor) from the road, but there could be lives saved while we wait. As sad as it is, there are still people that refuse to wear a seatbelt, so who knows how much throwing technology at the problem would help, but it’s worth a shot.