flying_hun
Adverse Selection
Wait! You mean Donald Rumsfeld is a guru? :wtf
Good Speed / Bad Speed
- Thread starter DataDan
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Wait! You mean Donald Rumsfeld is a guru? :wtf
flying_hun
Adverse Selection
RGal quoted him in her post...... :laughing
DataDan
Mama says he's bona fide
Roadstergal posted that in quotation marks, so I assume she got it from somewhere else. But it's a semi-profound observation. And I think it's a good way to consider motorcycling risks.
Lou, as you approach an intersection where an oncoming vehicle is waiting to turn left, you're facing a known-unknown. You know from experience that cars can turn left in front of motorcycles. But you don't know whether this particular bozo, at this particular time, is going to turn in front of you. Your action in the face of the known-unknown is to plan for the contingency of the car turning. If it does, you're ready, and it's probably not going to hit you.
Now consider a raw noob. His only experience on the road is in a car, and it's fairly unlikely that a car will turn left in front of another car. For one, cars are easy to see. And for another, cars don't accelerate hard or dart out suddenly from behind other vehicles. So our noob, drawing only on his cage experience, isn't considering the possibility that the car is going to turn left in front of his motorcycle. For him, this situation is an unknown-unknown. Not only does he not know whether the oncoming car is going to turn left, he's not even aware of the possibility.
Developing riding judgment can be thought of as cataloging known-unknowns. When you first experience one, it's an unknown-unknown, and your reaction is "Holly Carp! Where did that come from?" But you remember it. You take a brick from the pile of unknown-unknowns and stack it with the known-unknowns. The next time you're in a similar situation--hopefully--you find the brick in the known-unknown stack that says, "Oncoming left-turner. Bad joo-joo."
Keep doing this for 20 or 30 years, and there's very little left in the unknown-unknown pile. That's called "experience".
Lou, as you approach an intersection where an oncoming vehicle is waiting to turn left, you're facing a known-unknown. You know from experience that cars can turn left in front of motorcycles. But you don't know whether this particular bozo, at this particular time, is going to turn in front of you. Your action in the face of the known-unknown is to plan for the contingency of the car turning. If it does, you're ready, and it's probably not going to hit you.
Now consider a raw noob. His only experience on the road is in a car, and it's fairly unlikely that a car will turn left in front of another car. For one, cars are easy to see. And for another, cars don't accelerate hard or dart out suddenly from behind other vehicles. So our noob, drawing only on his cage experience, isn't considering the possibility that the car is going to turn left in front of his motorcycle. For him, this situation is an unknown-unknown. Not only does he not know whether the oncoming car is going to turn left, he's not even aware of the possibility.
Developing riding judgment can be thought of as cataloging known-unknowns. When you first experience one, it's an unknown-unknown, and your reaction is "Holly Carp! Where did that come from?" But you remember it. You take a brick from the pile of unknown-unknowns and stack it with the known-unknowns. The next time you're in a similar situation--hopefully--you find the brick in the known-unknown stack that says, "Oncoming left-turner. Bad joo-joo."
Keep doing this for 20 or 30 years, and there's very little left in the unknown-unknown pile. That's called "experience".
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Nemo Brinker
Tonight we ride
BARF is a great place (and mentoring is even better) to get wise to the known-unknowns, without having to experience them as potentially fatal unknown-unknowns first.
Any speed can reduce one's ability to use experience to handle the unknown in sufficient time to avoid it.
Any speed can reduce one's ability to use experience to handle the unknown in sufficient time to avoid it.
This is a good point.. you get a little experience in the cage.. likely someone has done it before.. but the level that this is done when you ride is a whole notha level.
I think that the standard driving practice for a cager comes no where close to what you have to be visually aware of on a bike. We have all see those "blinder on" drivers that just are in the straight ahead zone and do very little checking to left right or mirrors or much else other than the bumper ahead. This is disaster waiting to happen on a bike..
The protocal should be similar to playing paint ball.. always looking for the guy that is going to shoot you from out of no where.. never fixating on anything for more than a sec.. plus we are moving at speed and circumstances change quickly.. constant updates to our left and right that could be potential dangers and constant in front of us as well. Who knows when that 2 x 4 will be lying in the road..??
I have ridden over timber/ladders/ and other surpise road debris more than a few times.. heavy traffic or night time hides this stuff often. BTW.. stand up and gas it over the timber..! The natural reaction is to brake.. and that is fine if you can make it in time, but if your going to hit it.. on the gas is better because the front wheel is not loaded and has a better chance to get over it...
So that brings up a question from me for the experienced..
What other riding skills (similar to the 2 x 4 mentioned above) can you share that would not be a regular riding skill that can help when cause arises??
Oh.. and Dan.. can I get a 40 years.. please.. 20 / 30 / 40!
:smoking
:smoking
DataDan
Mama says he's bona fide
Pathological thinking about speed--and the lack of strategy for managing speed--can be seen in a current thread at Sportbikes.net, How often do you speed? Some of the posts are thoughtful and reflect an attitude that has probably kept the rider safe. Others are just inane.
But none reveal an objective approach that tries to make sense of safer speed. What makes X mph, or speed limit + X, safe? What are the factors that need to be accounted for in determining a safe speed?
Ask a different question, "What gear do you wear?", and you'd get pages of apparel inventories, discussions of the pros and cons of various materials and designs, and flame-fests between Joe Rocket and a* wearers. But there would be lots of basic ideas in common about the necessity of gear and kinds of protection it can provide.
What I'm trying to develop with this thread is an easily applied speed strategy based on fundamental principles. It would be great if, someday in the not-too-distant future, a discussion about speeding came up at BARF and a post that said merely "I ride 10-20mph over the limit" would produce a flurry of critical replies. Not complaining that +10-20 is unreasonable in all situations. But pointing out factors such as sight distance, following distance, speed differential, reaction time, and braking distance that must be taken into account before a rider can decide what speed is appropriate.
But none reveal an objective approach that tries to make sense of safer speed. What makes X mph, or speed limit + X, safe? What are the factors that need to be accounted for in determining a safe speed?
Ask a different question, "What gear do you wear?", and you'd get pages of apparel inventories, discussions of the pros and cons of various materials and designs, and flame-fests between Joe Rocket and a* wearers. But there would be lots of basic ideas in common about the necessity of gear and kinds of protection it can provide.
What I'm trying to develop with this thread is an easily applied speed strategy based on fundamental principles. It would be great if, someday in the not-too-distant future, a discussion about speeding came up at BARF and a post that said merely "I ride 10-20mph over the limit" would produce a flurry of critical replies. Not complaining that +10-20 is unreasonable in all situations. But pointing out factors such as sight distance, following distance, speed differential, reaction time, and braking distance that must be taken into account before a rider can decide what speed is appropriate.
GAJ
Well-known member
Reaching down to flip the petcock to reserve at 70mph going uphill through sweepers, no shoulder for safety, with a sputtering engine and following cage traffic because you were a dumbass and thought your tiny SM gas tank would make the two miles to your house. :wtf
Don't ask me how I know. :teeth
louemc
Well-known member
Right (I think), there are variables to draw on, I'm not leaving things to chance (that's like playing Russian Roulette). I like to use cars to run interference for me, or in an intersection I'm going slow enough to toss my bike onto a different line if I have to. Everything combined, has kept me healthy for 52 years of this.
I find that the main things are the same everywhere (out in the sticks and in the dense city and the intersection at Alices).
1. your on a motorcycle
2. you have everything riding on exercising correct judgement of the situation.
3. being able to tell your bike what you want it to do, so you are in control of what happens.
4. incompetent, distracted, unqualified to drive, drivers are everywhere.
Then different area's have different variables and intensity of how fast they come at you. You have to be able to handle everything everywhere, and more. Some day something will come at you, worse than you can believe, but if your disciplined to ride with intense focus, there is a very good chance you will handle the event.
Roadstergal
Sergeant Jackrum
It's the odd thing he accidentally got right. An unknown known, really.
http://www.slate.com/id/2081042/
DataDan
Mama says he's bona fide
SPEED STRATEGY: Rule 1
Speed, Space, and Time
If you're going to ride a motorcycle fast and want to do it in relative safety, you have to understand the importance of space and time.
You need space to decelerate or to change direction--more speed, more space. As you go faster, you need greater distance to brake to a stop, greater distance to swerve around an obstacle, and greater distance to lean the motorcycle into a curve. And it's not simply a proportional increase. For example, if you can brake to a stop from 60mph in 160 feet, the same braking force will stop you from 120mph in 640 feet. Because of that, the rule is modified for higher speeds (see below).
Time goes along with space, of course: you need space to make an evasive maneuver, and you need time to execute it. But time gives you something else too: the opportunity to track a moving threat so you can avert the intrusion altogether. For example, a careless driver merging onto the freeway may force you to brake to avoid rear-ending him. But if you spot him before he reaches you, when he cuts off someone in the next lane, you can gently accelerate or roll-off to eliminate the threat completely. The earlier you identify a potential problem, the less severe the action needed to avoid it.
This rule dictates a speed consistent with the environment and ensures that you have enough time and space to respond to a hazard that suddenly appears. Make it the cornerstone of your speed management strategy and follow it as if your life depends on it. Because it does.
Application of the Rule
The 4-second sightline interval is what MSF calls your "immediate path of travel." If an obstacle appears 4 seconds ahead, you'll have just enough road to brake to a stop before you reach it. But if you fly into a blind turn with less sight distance and the road is blocked by a pile of crashed motorcycles, you're probably going to join it.
Note that this isn't the same as the 2-second following distance rule taught by MSF. The 2-second rule gives you time to react to when a vehicle ahead moving at the same speed as you brakes unexpectedly. The 4-second rule applies to the road itself, and it gives you the distance you need to avoid an obstacle that comes into view.
You probably know how to count a time interval from MSF: Spot a point in the road ahead and count out loud, "one one-thousand, two one-thousand,..." until you reach that point. But it isn't necessary to continually count out the sightline interval. With practice, you will quickly develop a sense for it so you can see the interval at a glance. On a straight, vacant stretch of road, take a guess at a 4-second interval and count it out. Adjust your guess and repeat until you've got it right. I've found that once acquired, the sense of it sticks permanently, though it's reassuring to calibrate it occasionally.
A few notes on the use of the rule:
This rule is derived from the "safe stopping distance rule" taught to riders in the UK: Maintain speed that allows you to stop in the distance you can see to be clear. Stated that way, it's harder to put into practice because of uncertainty about stopping distance and the difficulty of estimating distance. Counting out seconds of travel is much easier, and it works just as well.
David Hough also recommends a time-based rule in Proficient Motorcycling, but I think his times are unrealistically high. If you're interested in my reasoning for the 4-second rule, send me a PM.
edit, 1/31/10: revised interval at 80+ to 5sec, lowering braking performance requirement
Rule 1: Maintain speed that allows you to see the roadway at least 4 seconds ahead.
Speed, Space, and Time
If you're going to ride a motorcycle fast and want to do it in relative safety, you have to understand the importance of space and time.
You need space to decelerate or to change direction--more speed, more space. As you go faster, you need greater distance to brake to a stop, greater distance to swerve around an obstacle, and greater distance to lean the motorcycle into a curve. And it's not simply a proportional increase. For example, if you can brake to a stop from 60mph in 160 feet, the same braking force will stop you from 120mph in 640 feet. Because of that, the rule is modified for higher speeds (see below).
Time goes along with space, of course: you need space to make an evasive maneuver, and you need time to execute it. But time gives you something else too: the opportunity to track a moving threat so you can avert the intrusion altogether. For example, a careless driver merging onto the freeway may force you to brake to avoid rear-ending him. But if you spot him before he reaches you, when he cuts off someone in the next lane, you can gently accelerate or roll-off to eliminate the threat completely. The earlier you identify a potential problem, the less severe the action needed to avoid it.
This rule dictates a speed consistent with the environment and ensures that you have enough time and space to respond to a hazard that suddenly appears. Make it the cornerstone of your speed management strategy and follow it as if your life depends on it. Because it does.
Application of the Rule
The 4-second sightline interval is what MSF calls your "immediate path of travel." If an obstacle appears 4 seconds ahead, you'll have just enough road to brake to a stop before you reach it. But if you fly into a blind turn with less sight distance and the road is blocked by a pile of crashed motorcycles, you're probably going to join it.
Note that this isn't the same as the 2-second following distance rule taught by MSF. The 2-second rule gives you time to react to when a vehicle ahead moving at the same speed as you brakes unexpectedly. The 4-second rule applies to the road itself, and it gives you the distance you need to avoid an obstacle that comes into view.
You probably know how to count a time interval from MSF: Spot a point in the road ahead and count out loud, "one one-thousand, two one-thousand,..." until you reach that point. But it isn't necessary to continually count out the sightline interval. With practice, you will quickly develop a sense for it so you can see the interval at a glance. On a straight, vacant stretch of road, take a guess at a 4-second interval and count it out. Adjust your guess and repeat until you've got it right. I've found that once acquired, the sense of it sticks permanently, though it's reassuring to calibrate it occasionally.
A few notes on the use of the rule:
- While 4 seconds is a good rule of thumb, it's not enough at higher speeds. Over 80mph add 1 second. Over 100mph, you're on your own.
- At speeds below 40mph, a 3-second interval gives you adequate braking distance. This would apply to many blind turns on the Bay Area's paved goat trails.
- The 4-second interval is valid if you're good on the brakes and the surface is clean and dry. If you're new, if you don't regularly practice hard braking, or if the road is wet, add 1 second. If you're a riding god capable of MotoGP-caliber braking even in an emergency, you can subtract a half-second.
- The rule tells you not only when to slow down, it also helps you identify spots where higher speed may be possible. Other considerations will limit speed, but at least the sightline interval will tell you if you have enough braking distance.
- The rule is usually easy to follow because you'll often have much more than 4 seconds. Coming on to a quarter-mile straight at 60mph you'll have 15 seconds of sight distance. Where the rule can save you is in a situation like cresting a hill or approaching a blind curve. When the sightline shortens to 4 seconds, it's telling you that you don't have enough information to continue at that speed. It helps you to distinguish between the yin and the yang--where the environment's inherent limits dictate restraint and where you can open it up and have some fun.
This rule is derived from the "safe stopping distance rule" taught to riders in the UK: Maintain speed that allows you to stop in the distance you can see to be clear. Stated that way, it's harder to put into practice because of uncertainty about stopping distance and the difficulty of estimating distance. Counting out seconds of travel is much easier, and it works just as well.
David Hough also recommends a time-based rule in Proficient Motorcycling, but I think his times are unrealistically high. If you're interested in my reasoning for the 4-second rule, send me a PM.
edit, 1/31/10: revised interval at 80+ to 5sec, lowering braking performance requirement
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louemc
Well-known member
I'll agree with that vision thing, GAJ. My eyeballs do not work as well with the head down, and the eyeballs tilted up to look forward, position.
And... as far as body lean (getting down) goes, I can do that just fine as the speeds go up. The times I'm in mid triple digits is very brief, and when there it's only when the road and conditions around the road, say it's safe. That's far different than being in the crouch all the time, because the clip-ons demand it, and the rider isn't willing to change those bars from a race replica placement to a public road placement, (or, make them right for the place the bike is getting used).
And... as far as body lean (getting down) goes, I can do that just fine as the speeds go up. The times I'm in mid triple digits is very brief, and when there it's only when the road and conditions around the road, say it's safe. That's far different than being in the crouch all the time, because the clip-ons demand it, and the rider isn't willing to change those bars from a race replica placement to a public road placement, (or, make them right for the place the bike is getting used).
DataDan
Mama says he's bona fide
SPEED STRATEGY: Rule 2
In 2007, 31 of the 91 fatal motorcycle crashes in the Bay Area occurred when the motorcycle ran wide in a curve and hit either an oncoming vehicle or a fixed object. And that's just the tip of the iceberg, because in many less serious crashes and near-crashes the motorcycle runs wide but doesn't make a fatal impact. Most such incidents can be prevented by getting entry speed right.
Even when entry speed permits a turn to be negotiated safely, a crash can occur. That's because a perception of excessive speed may cause the rider to panic, lose visual focus on his planned line, chop the throttle, grab the brake, or intentionally ride into the oncoming lane or off the road. The VP helps manage speed and perceive it accurately by focusing attention in the right place.
The speed profile dictated by the VP technique is slow in/fast out, which is generally accepted as good practice because the motorcycle is accelerating through the turn. But an additional advantage is that you're slowing when uncertainty is greatest. As you approach a turn, you don't know what the surface is like, where the tightest point is, or maybe even which way it goes. By continuing to decelerate as you near the tightest part of the turn, you're prepared for whatever might appear. And by waiting until you see the turn opening up before you accelerate, you won't get back on the gas too soon.
While the VP rules tell you when to decelerate and accelerate, they don't tell you how fast to take a turn, so experience and judgment are still needed. What the technique provides is essential information you need to exercise good judgment.
Rule 2: Use the Vanishing Point technique to control speed in turns.
The Vanishing Point is the furthest bit of pavement you can see ahead of you, where the road disappears around a bend or over a rise.
The Vanishing Point is the furthest bit of pavement you can see ahead of you, where the road disappears around a bend or over a rise.
- As you approach a turn and the VP is getting closer, slow down. Roll off the gas, and brake if necessary.
- In mid-turn when the VP is staying a fixed distance ahead, maintain constant speed with a little throttle.
- At exit when the VP is disappearing into the distance, roll on the gas and accelerate, again matching the throttle to the VP's progress.
In 2007, 31 of the 91 fatal motorcycle crashes in the Bay Area occurred when the motorcycle ran wide in a curve and hit either an oncoming vehicle or a fixed object. And that's just the tip of the iceberg, because in many less serious crashes and near-crashes the motorcycle runs wide but doesn't make a fatal impact. Most such incidents can be prevented by getting entry speed right.
Even when entry speed permits a turn to be negotiated safely, a crash can occur. That's because a perception of excessive speed may cause the rider to panic, lose visual focus on his planned line, chop the throttle, grab the brake, or intentionally ride into the oncoming lane or off the road. The VP helps manage speed and perceive it accurately by focusing attention in the right place.
The speed profile dictated by the VP technique is slow in/fast out, which is generally accepted as good practice because the motorcycle is accelerating through the turn. But an additional advantage is that you're slowing when uncertainty is greatest. As you approach a turn, you don't know what the surface is like, where the tightest point is, or maybe even which way it goes. By continuing to decelerate as you near the tightest part of the turn, you're prepared for whatever might appear. And by waiting until you see the turn opening up before you accelerate, you won't get back on the gas too soon.
While the VP rules tell you when to decelerate and accelerate, they don't tell you how fast to take a turn, so experience and judgment are still needed. What the technique provides is essential information you need to exercise good judgment.
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flying_hun
Adverse Selection
Dan, have you ever read Roadcraft, the UK book for moto-LEO's? I've heard that it utilizes VP quite a bit, but I've never read it.
DataDan
Mama says he's bona fide
Yes I have. The official title is Motorcycle Roadcraft, and it's available from Amazon. I cite it as the source of the VP technique in the Training thread, though the authors use the term "limit point".
flying_hun
Adverse Selection
Does that constitute a recommendation then?
GAJ
Well-known member
Shouldn't any discussion of the valuable Vanishing Point concept when it comes to cornering include a discussion of how to late apex and where to position your bike to do so in left turns vs. right turns?
As I'm sure you have discussed that at length before, DD, I'll let you pull that archive from your excellent bag of knowledge...you know, the DDEBOK.
As I'm sure you have discussed that at length before, DD, I'll let you pull that archive from your excellent bag of knowledge...you know, the DDEBOK.
DataDan
Mama says he's bona fide
While I like late apexing--which should really be called "wide, late turn-in" (WLTI) because its benefit is in improving sightline at turn entry, and the apex point is more or less coincidental--I don't think it needs to be covered here. In addition, WLTI is only one consideration in line selection. Positioning yourself near the double-yellow as you approach a blind right-hander can sometime create serious danger from an oncoming centerline cheater. It all depends on how limited the sightline is.
As I wrote earlier in this thread:
What I’m trying to do in this thread is sketch out a strategy for managing speed that distinguishes between Good Speed and Bad Speed. That is, one that identifies a sharp line between good clean fun and potentially deadly excess. Short of finding a way to instill good judgment, a strategy that can be employed by following a few simple rules is the most we can hope to accomplish.