Hemmings Motor News Blog Blog

Hemmings Motor News Blog

Hemmings Motor News has been around since 1954. We're proud of our heritage, but we're also more than the Hemmings full of classifieds that your father subscribed to. Aside from new editorial content every month in Hemmings, we have three monthly magazines: Hemmings Muscle Machines, Hemmings Classic Car and Hemmings Sports and Exotic Car.

While our editors traverse the country to find the best content for those magazines, we find other oddities related to the old-car hobby that we really had no place for - until now. With this blog, we're giving you a behind-the-scenes look at what we see and what we do during the course of putting out some of the finest automotive magazines you'll ever read.

Previous in Blog: Skills 101: How to Heel-Toe Downshift   Next in Blog: Skills 101 – Oversteer and Understeer Explained
Close
Close
Close
23 comments
Rate Comments: Nested

Skills 101: Threshold Braking

Posted April 30, 2013 8:00 AM by dstrohl
Pathfinder Tags: braking skills 101 threshold

In the days before Anti-Lock Brakes (ABS) came as standard equipment on all new cars, beginning drivers were often taught to "pump the brakes" in a panic stop, as this was perceived to be the easiest way to prevent brake lock-up. Locking the brakes not only produced longer stopping distances, but also wore flat spots on tires and eliminated any steering control a driver might otherwise have.

Progress beyond the basics of driving by attending an advanced driving or racing school, and a technique called "threshold braking" was generally part of the curriculum. Though easy to describe (apply the brakes to just before the point of tire lock-up, as quickly as you can), mastering the technique of threshold braking took practice and generally involved the swatting of many traffic cones in practice exercises.

For the video and more info, visit Hemmings Daily.

Reply

Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Good Answers:

These comments received enough positive votes to make them "good answers".
4
Guru
Popular Science - Evolution - New Member Popular Science - Weaponology - New Member

Join Date: May 2006
Location: The 'Space Coast', USA
Posts: 11119
Good Answers: 918
#1

Re: Skills 101: Threshold Braking

04/30/2013 9:01 AM

ABS improves stopping distance in wet and icy conditions, but actually lengthens the stopping distance on dry pavement.

ABS is not designed to stop faster than non-ABS equipped cars, but allows the neophyte to both brake and turn the car, which is not readily possible in a skid.

The downside of a skid is flat spotting on the tire, however, in an emergency stop tires are usually not as important as occupant safety.

Dry road skids should provide a quicker straight-line stop than ABS and pumping of brakes. The reason is that there are more factors in play than simple friction (static and dynamic) as most physics students would think.

Besides the road surface itself, tire temperature drastically impacts performance. Skidding will heat the tire surface and actually improve the coefficient of friction under the right circumstances.

However, threshold braking is the way to go when performance driving. Most of us are not racers, so ABS is a blessing.

Some insurance companies have complained that ABS has actually contributed to more accidents. The issue is that it provides a false sense of confidence for may drivers. Unfortunately, driver's education programs in schools never teach students to experience handling of cars at their limits, so students have no idea what those limits are and what to do when those limits are crossed.

Many performance driving schools, on the other hand, do teach students what to do when they exceed the limits. Bob Bondurant School of High Performance Driving is one that created a specially fitted car that was designed to emulate wet, snow, and ice conditions so students can feel the warning signs and learn how to correctly react to those indications.

I think these practices should be adopted by more schools. It might help save lives.

Reply Good Answer (Score 4)
Guru

Join Date: Oct 2008
Posts: 42355
Good Answers: 1693
#2
In reply to #1

Re: Skills 101: Threshold Braking

04/30/2013 2:26 PM

I was fortunate enough to take a short, one day class at the GM Desert Proving Grounds, formerly in Mesa AZ about 5 years ago. They train their drivers in high speed maneuvering, braking, rapid lane changes, etc.

One of the most fun parts was the skid pad. The instructor had a switch that he used to lock the rear brakes, and the driver never knew when that would be.

That was a fun, informative day.

Reply
Guru

Join Date: Sep 2008
Posts: 706
Good Answers: 32
#3
In reply to #2

Re: Skills 101: Threshold Braking

04/30/2013 4:49 PM

My father took me out at 16 on a snowy Sunday morning in Connecticut to the local A&P parking lot. The stores were closed on Sundays back then and the lot was empty. As I was driving through the lot he reached over and jerked the steering wheel, throwing the car into a skid. I yelled out "Are you crazy". He said 'Nature never gives you a warning so you need to be prepared for the unexpected." After 45 minutes of that it became second nature on how to control the car in a skid, not to hit the brakes but use the clutch and downshift. I taught my kids the same way at an Industrial Complex near our home. They yelled too. Now I would it for fun but never seem to find that empty lot. Had to teach them to use Neutral though instead of the clutch since our cars then all had automatic.

__________________
Spinco
Reply
Guru
Popular Science - Evolution - New Member Popular Science - Weaponology - New Member

Join Date: May 2006
Location: The 'Space Coast', USA
Posts: 11119
Good Answers: 918
#4
In reply to #3

Re: Skills 101: Threshold Braking

04/30/2013 6:20 PM

Snowy empty lots are the best.

I had a colleague fly in from India and she needed to get her driver's license, but was terrified driving. Can't imagine why. Have you seen how people drive in India?

Anyway, after a number of road trips she just could not get the hand of it, so I drove her to the company lot and drove some gentle loops in the snow and asked her to try that.

After a lap or two I had her try to speed up. It took a lot of coaxing, but she finally did and when the tail broke loose she screamed. I kept at it and after a few minutes the fear subsided and she was doing full figure 8s in the lot and grinning ear to ear until the guard made us stop. She just would not stop!

After that her driving was much better and she had both a respect for the car and road conditions and an understanding of how to control the car in a slide.

Reply
Guru

Join Date: Oct 2008
Posts: 42355
Good Answers: 1693
#5
In reply to #4

Re: Skills 101: Threshold Braking

04/30/2013 8:06 PM

OT, but I spent a week in Toronto at a trade show with two PhD engineers who were co-workers. One from China and one from England, who had grown up in India, then gone back to England. We agreed that each of us would drive alternating days. What a mistake that was.

Needless to say, I feared for my life many times that week.

And volunteered to drive every day after the guy from China took the wheel the first time.

Reply Off Topic (Score 5)
Guru

Join Date: Nov 2012
Posts: 633
Good Answers: 13
#15
In reply to #5

Re: Skills 101: Threshold Braking

05/01/2013 3:24 PM

While living in the SF bay area I learned to 'fear' chinese drivers...was told by a chinese desent co-worker 'How do you blind a chinaman?...put a windshild in front of them'. I have seen left turns from the right lane, right turns from the left lane, vehicles on the freeway (70mph traffic) cross from the center lane at 30mph to an exit ramp they'd almost missed. ALL oriental looking drivers. Noting these things is 'politically incorect. I think they should be given EXTENSIVE annual driving tests in various road conditions and FAIED if they can't pass. Just for looking oriental should be enough reason. Same thing for Sighks who drive in America, dieing on the freeway is not a thing of honor.

Reply Off Topic (Score 5)
Guru

Join Date: Oct 2008
Posts: 42355
Good Answers: 1693
#17
In reply to #15

Re: Skills 101: Threshold Braking

05/01/2013 3:27 PM

I think a lot of the bad driving can be attributed to the fact that many immigrants may have never even ridden in a car until coming to the USA.

Reply Off Topic (Score 5)
Guru

Join Date: Sep 2008
Posts: 706
Good Answers: 32
#18
In reply to #4

Re: Skills 101: Threshold Braking

05/01/2013 4:39 PM

One of the most harrowing rides of my life was when we had just left the British Swim Club in Bombay after eating there. We grabbed a taxi back to the ship. We told the taxi driver (a Sikh) to show us some sights on the way back. He took off like a bat out of hell with no lights on (lights use up gas- very expensive says he). The street lighting was not too good and people often walk the streets as they see fit. People in your way, reach down and honk your Bombay Taxi Horn, squeeze the big rubber bulb, manual power- no gas wasted. If they don't move and you're getting closer-blink your lights as you honk the horn (look Ma- no hands). As we careened through the streets of The Cages, weaving through the crowds, I was amazed that there were no fallen bodies in our wake. It was the ride of a lifetime. Got into a cab in NYC once and the driver was wearing his turban and obviously a Sikh. Asked him "What, no Bombay Taxi horn." He laughed. Told me he actually did learn to drive in Bombay as a taxi driver but had to re-learn how to drive one here since the consequences of hitting a pedestrian in NYC were much more severe than in India.

__________________
Spinco
Reply
Power-User
United States - Member - New Member Engineering Fields - Biomedical Engineering - Radiation Oncology Engineering Hobbies - Fishing - New Member APIX Pilot Plant Design Project - Member - New Member Hobbies - Hunting - New Member Hobbies - DIY Welding - New Member Hobbies - Target Shooting - New Member Popular Science - Biology - New Member

Join Date: Sep 2006
Location: CT
Posts: 267
Good Answers: 1
#9
In reply to #3

Re: Skills 101: Threshold Braking

05/01/2013 7:29 AM

I did the same thing, without my father, when I was 17. Went to a large unimpeded snow filled parking lot in Bloomfield CT. I started at one end of the lot and about halfway turned the wheel. I would do this every storm that years. This was valuable training. I would recommend doing this if you can find an unimpeded lot today.

I do believe this training saved me on several occasions since.

__________________
“Sometimes we don't even realize what we really care about, because we get so distracted by the symbols.” ? Tom Wolfe, The Electric Kool-Aid Acid Test
Reply
Guru

Join Date: Sep 2008
Posts: 706
Good Answers: 32
#13
In reply to #9

Re: Skills 101: Threshold Braking

05/01/2013 10:06 AM

I was in New Milford and only had my permit then but oh yes, after I got my license at 17 I too went out on my own and practiced that following winter. Back then we had the stock car races in Danbury so it was fun to imitate that feeling with a little bit of safety in the A&P lot. And we always seemed to have plenty of snowy weekends to practice in.

And as many said, the experience was invaluable and came in handy on even rainy days.

__________________
Spinco
Reply
Guru

Join Date: Aug 2012
Location: Land of Fruits and Nuts
Posts: 4481
Good Answers: 54
#6
In reply to #1

Re: Skills 101: Threshold Braking

05/01/2013 2:19 AM

Hero, In college, I remember a physics problem related to dry pavement non-ABS vs ABS distances. Non-ABS cars would stop shorter when the brakes were locked vs threshold braking. The coefficient of friction would not decrease when the brakes were locked and actually did the opposite. So the fastest way to stop was in a non-ABS vehicle with the brakes locked.

__________________
Enjoy and be happy! Life is too short!
Reply
Power-User

Join Date: Jul 2010
Location: North Carolina, USA
Posts: 423
Good Answers: 9
#14
In reply to #1

Re: Skills 101: Threshold Braking

05/01/2013 1:03 PM

When I took Drivers Ed in 1977 at Page HS in Greensboro, NC we had a driving track with a skid pad, lane change cones, and several cars to practice in before getting on public streets. We did emergency maneuvers in a Plymouth Fury III police cruiser with a passenger side rear brake pedal for the instructor.

It was probably expensive, but I am sure the extra training saved some young lives, including my own. In today's environment of trying to do public services like education on the cheap, all the NC public schools do now is teach the test and 6 hours of in car training, which does not mean 6 hours of driving.

Here's a free alternative for new drivers: http://driversedge.org/.

My daughter did this day course and I think it helped quite a bit with keeping her safe.

Reply
Guru

Join Date: Aug 2012
Location: Land of Fruits and Nuts
Posts: 4481
Good Answers: 54
#19
In reply to #14

Re: Skills 101: Threshold Braking

05/04/2013 4:17 AM

Our Driver's Ed was at Maine East High School in Park Ridge, IL. A local dealership donated cars for us to use. They were pretty nice cars back then (1982 for me). We had Olds Cutlass Sedans. We drove on streets and our instructor had brakes, but I don't think he had steering (I could be wrong).

Here in So Cal, the kids don't get behind the wheel driving. They get classroom Driver's Ed and the behind the wheel part is done at a private company (which the parents pay for). I'm not sure if this is true for the rest of the country.

__________________
Enjoy and be happy! Life is too short!
Reply
Guru
Popular Science - Weaponology - New Member Safety - ESD - New Member Hobbies - Fishing - New Member

Join Date: Sep 2006
Location: Near Frankfurt am Main, Germany. 50.390866N, 8.884827E
Posts: 17996
Good Answers: 200
#16
In reply to #1

Re: Skills 101: Threshold Braking

05/01/2013 3:25 PM

I liked your post.

Basically, a well trained driver can stop his non ABS car quicker in all conditions, even in snow and loose gravel, where the "wedge effect" helps to slow the car down faster, where an ABS car does not allow the wedge to build up for example.....

20 years ago, German car insurance companies required higher premiums for both ABS and/or 4 wheel drive fitted cars as they actually had more accidents and more serious accidents.....

A neophyte in an ABS fitted car, who "saws" on the wheel, goes off road generally speaking.....which can be far more dangerous than running into the back of the car in front.....or killing a cat or a dog......

__________________
"What others say about you reveals more about them, than it does you." Anon.
Reply
Guru

Join Date: Aug 2012
Location: Land of Fruits and Nuts
Posts: 4481
Good Answers: 54
#7

Re: Skills 101: Threshold Braking

05/01/2013 2:43 AM

A few years ago, I was driving on wet pavement in my new car (with ABS). Traffic around a blind corner (as I was entering a tunnel) came to a stop and I put my foot to the floor in panic and thought I was going to slide into the car in front. Lo and behold, the ABS kicked in and the car stayed in my lane and stopped just short of an accident. After this near miss, I realized that I'll take ABS over non-ABS. When inclimate weather exists (as is the case for most of us), I am an advocate of ABS.

__________________
Enjoy and be happy! Life is too short!
Reply
Guru

Join Date: Aug 2012
Location: Land of Fruits and Nuts
Posts: 4481
Good Answers: 54
#8

Re: Skills 101: Threshold Braking

05/01/2013 2:50 AM

One final comment. New cars not only come with ABS, but they have EBD, Brake Assist and Toyota has Smart Stop Technology. EBD (Elec Brakeforce Dist) helps by taking the braking power from a wheel ready to slip and transferring the braking power to the wheels with better grip (no professional can do this). Brake Assist helps by sensing a panic stop situation and increasing the braking force. Smart Stop Technology limits the throttle when the brake pedal is depressed - keeps people from mistakenly driving with gas and brake pedal depressed (like all the Toyota unintended acceleration claims).

A few weeks ago, I delivered a new 2013 Honda Accord EX sedan with lane departure, side view camera (when changing lanes) and a warning when the distance between you and the car in front is rapidly decreasing. All this for a Honda Accord! I love it.

__________________
Enjoy and be happy! Life is too short!
Reply
Guru
Popular Science - Evolution - New Member Popular Science - Weaponology - New Member

Join Date: May 2006
Location: The 'Space Coast', USA
Posts: 11119
Good Answers: 918
#10
In reply to #8

Re: Skills 101: Threshold Braking

05/01/2013 8:44 AM

My car (2004) also has the throttle limiter when the brake is depressed. It tales a few seconds to kick in.

I discovered that when I was trying to heat up the brakes prior to using them (the pads' grip improves when up to temperature, just like tires). I could only press the brake and gas for a short time before it overrides the throttle.

Racers routinely do this prior to a turn after a long straight to squeeze the most performance out of the car.

Racers also do 70% (or more) of their braking while the steering wheel is straight as they enter the turn.

Braking in a turn is the worst because the car's balance is upset such that the inside wheels get much less traction as the weight distribution shifts.

As you enter the turn you are relaxing the brake force as you transition to the gas to begin accelerating.

The whole secret to racing is being smooth. Sudden shifts in the direction of the car or its acceleration will upset the balance of the car and you loose traction.

The same thing happens on the street, but to a lower degree. However, driving smoothly still helps avoiding accidents, particularly when conditions are slippery.

I cut my driving teeth in the snowy North East and I learned (and became quite proficient) how to navigate roads that most people could not and I did that in rear wheel drive cars. Technique is everything.

Reply
Guru

Join Date: Aug 2012
Location: Land of Fruits and Nuts
Posts: 4481
Good Answers: 54
#20
In reply to #10

Re: Skills 101: Threshold Braking

05/04/2013 4:40 AM

The new Toyota Smart Stop Technology is pretty neat. If you press the brake and accelerator at the same time it will do one of two things - if you press the accelerator first and the brake second, it will reduce power from the engine (drive by wire). If you press the brake first and the accelerator second, the car will think you're trying to start on an uphill and will give you power.

Hot brake pads and rotors are good to a point. Hard ceramic pads need heat or they don't work well. If rotors get too hot, they most likely will warp. The exception is the new carbon fiber rotors.

You're 100% correct that smooth driving is the key to racing. When I watch F1 drivers, I'm amazed at how well they pick lines and how smooth they are. And it's all at high speeds. They make it look easy!

Technique is key and a good driver can make a lowly Toyota Prius move pretty well. I saw a Top Gear episode where the gal from the German Top Gear (Sabine?) took an Econoline van on the Nurburgring and ran a pretty good time - she was passing 911's!

__________________
Enjoy and be happy! Life is too short!
Reply
Guru
Popular Science - Weaponology - New Member Safety - ESD - New Member Hobbies - Fishing - New Member

Join Date: Sep 2006
Location: Near Frankfurt am Main, Germany. 50.390866N, 8.884827E
Posts: 17996
Good Answers: 200
#22
In reply to #20

Re: Skills 101: Threshold Braking

05/04/2013 6:38 AM

The great Nigel Mansell was one of the few who could get by with "Bullying" a F1 car around the track, he was well known for it!!! I cannot think of another at this time, but there might be one or two more....

But you are right, the majority of the good ones are silky smooth......Great sport!!!

Here are a few good links, the first one mentions his "muscular" style of driving:-

http://www.bbc.co.uk/sport/0/formula1/18492552

http://vimeo.com/55923524

__________________
"What others say about you reveals more about them, than it does you." Anon.
Reply
Guru

Join Date: Aug 2012
Location: Land of Fruits and Nuts
Posts: 4481
Good Answers: 54
#23
In reply to #22

Re: Skills 101: Threshold Braking

05/04/2013 6:46 PM

There is a toughness in the British. Similar to the toughness in people from Boston or Chicago.

Nigel was one heck of a driver. These guys are absolutely amazing! Thanks for sharing.

__________________
Enjoy and be happy! Life is too short!
Reply
Guru
Popular Science - Weaponology - New Member United Kingdom - Member - New Member

Join Date: May 2007
Location: Harlow England
Posts: 16512
Good Answers: 670
#11

Re: Skills 101: Threshold Braking

05/01/2013 9:13 AM

Yup, when my daught' was learning I got her driving round a snowy car park in 2nd gear (manual box) and every now and then I'd smack on the handbrake as she was turning.
She soon got the hang of it and was drifting it round the bends.

A year or so later she got caught down some country lanes in snow and was able to cope no prob.

ABS was good initially... now everyone tailgates even worse... 'cos I've got ABS' they should all try riding a motorbike on a wet greasy road.

Del

__________________
health warning: These posts may contain traces of nut.
Reply
Active Contributor

Join Date: Mar 2012
Posts: 12
Good Answers: 1
#12

Re: Skills 101: Threshold Braking

05/01/2013 10:01 AM

I learned incipient breaking in a driving course some years ago- the trick I was taught was to sense when the hood of the car (which is dipping of course as you break) starts to come back up - this indicates the breaking is losing effectiveness ( as the load is coming off the suspension) due to tire / road slippage.

As that happens lift your breaking foot effort ever so slightly and you have incipient breaking conditions (hood dips a little again). Its not easy at first to see the change but you can with a little practice.

Now it begs a question, does this mean that the breaking effect goes through 3 phases

1) first stage - applying more and more force to the peddle you are stopping better and better

2) second stage - you go over what the tires can sustain (friction wise) at this point - call it the incipient point - so if you are practicing incipient breaking OR if you are using the ABS then both methods lift pressure (one for sensing via visual hood motion - the other from wheel rotation)

3) third stage - and only if you didn't lessen breaking effort, the tires do slip BUT then they heat up so much they grip even more (call it "panic breaking") and actually stop shorter

If this were so wouldn't all "panic breaking" be best for stopping distance?? (neglecting trying to steer from the equation, just stopping distance...which is not a good idea of course)

Reply
Guru

Join Date: Aug 2012
Location: Land of Fruits and Nuts
Posts: 4481
Good Answers: 54
#21
In reply to #12

Re: Skills 101: Threshold Braking

05/04/2013 4:50 AM

If you try this yourself, you'll find that the shortest braking occurs when the tires lock - this is for dry ground, not wet. It's hard to do this now, because ABS is in almost all cars, but if you have an older car, give it a shot. Of course you'll put flat spots on your tires - not a good thing.

When the ground is wet, snowy or icy, I agree with your incipient braking technique. I like the idea of watching the hood to see if it rises (means tires have lost some friction and weight is shifting away from the front).

The reason ABS works so well is that the pulsation of the brakes is much faster than a human can do.

One final note. Some people feel they are better than the new safety features on cars. On snowy/icy ground, I don't know anyone who can stop better (with non-ABS) than a car with a mediocre driver, but with modern ABS. Ditto for those new paddle shifters tied to a dual clutch manual transmission - they're quicker than the best race car drivers. I for one enjoy a manual transmission, but I must say that the new modern paddle shifters are pretty good.

__________________
Enjoy and be happy! Life is too short!
Reply
Reply to Blog Entry 23 comments

Good Answers:

These comments received enough positive votes to make them "good answers".
Copy to Clipboard

Users who posted comments:

Andy Germany (2); Anonymous Hero (3); Autobroker (7); geraldpaxton (1); JRiversW (1); lyn (3); rlindey (1); Spinco (3); ss3e55 (1); user-deleted-1105 (1)

Previous in Blog: Skills 101: How to Heel-Toe Downshift   Next in Blog: Skills 101 – Oversteer and Understeer Explained

Advertisement