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Thread: Two "4 second rules"

  1. #16
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    OP restating the question

    "How many seconds of road do you see riding blind twisties or cresting a hill?"

    Take the test on your next ride where these conditions apply ("1000 and one, 1000 and two...) Do you see four or more seconds ahead of you? Are you pretty confident you could stop (within your current count) if there was a fallen tree or vehicle blocking your lane? If not, are you comfortable riding beyond your stopping distance? I ask, because I think a lot of very experienced riders do just that - and many of them have lots more years and miles under their belt than I.

    Most posts have been about following distance. Important topic and several great posts on it. Just not the question I asked. I think the experienced and thoughful riders on this forum have more to say about the question in the first sentence in this post. It was also not something that came up many years ago when I took two MSF courses. I look forward to your responses.
    Doug
    1992 K100RS

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    I like that sign. but the second rider should be shown upside down!! As any racer knows, the last guy in a train heading for a braking zone needs to be the first guy to go for the brakes to be sure of staying out of mess- very counterintuitive to most street riders....


    The answer to the question is a bit over 2 seconds for blind curves in the NC mountains at normal speeds. So there is inherent risk in normal riding- you won't always have stopping distance or even avoidance maneuver distance....All the more reason not to up the pace if you value your bones. For reinforcement, take a look at the published pics of 18 wheelers coming the other way occupying both lanes in the tight spots of these blind curves. Even less avoidance time- its sometimes impossible and at least one death on the Dragon in the past couple seasons resulted from a case of this...Regrettably, there is no way to eliminate all risks if one rides blind twisties..(I find the Dragon a bit tedious and prefer stuff with wider turns, higher speeds and better visibility. Best reason to go there is to see the show at the joint at its start).

  3. #18
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    Quote Originally Posted by racer7 View Post
    The answer to the question is a bit over 2 seconds for blind curves in the NC mountains at normal speeds.
    Yeah, in supertwisties you're already around the entire turn in four seconds.

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    This is a very interesting and important discussion.

    I try to keep to 3 to 4 seconds in all traffic, except NYC where I live (but thats a whole other - terrible - place to ride). I think it provides enough time to respond to things like cars without brake lights and debris hidden by the vehicle in front - but sometimes creates enough distance that aggressive drivers decide you are moving too slowly (and do their best to try to kill you for the infraction).

  5. #20
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    Quote Originally Posted by racer7 View Post
    I like that sign. but the second rider should be shown upside down!! As any racer knows, the last guy in a train heading for a braking zone needs to be the first guy to go for the brakes to be sure of staying out of mess- very counterintuitive to most street riders....


    The answer to the question is a bit over 2 seconds for blind curves in the NC mountains at normal speeds. So there is inherent risk in normal riding- you won't always have stopping distance or even avoidance maneuver distance....All the more reason not to up the pace if you value your bones. For reinforcement, take a look at the published pics of 18 wheelers coming the other way occupying both lanes in the tight spots of these blind curves. Even less avoidance time- its sometimes impossible and at least one death on the Dragon in the past couple seasons resulted from a case of this...Regrettably, there is no way to eliminate all risks if one rides blind twisties..(I find the Dragon a bit tedious and prefer stuff with wider turns, higher speeds and better visibility. Best reason to go there is to see the show at the joint at its start).
    Racer 7, if I understand you correctly, you regularly ride blind twisty roads at speeds where you don't have adequate stopping distance or swerving distance. You regard this as "normal speeds," not excessive speed. Hey, I get the fact that there is no way to "eliminate all risks" wherever or however you ride a motorcycle. I also get the fact that 99.78 per cent of the time there will NOT be something in your path when you round a blind curve. Do it often enough though and the odds are not in your favor.

    Any other explanation of how you have avoided a serious accident with this riding behavior over many years and curves?
    Doug
    1992 K100RS

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    Effective riding, in the twisties or in traffic, is about constant analysis of your environment, and always evaluating everything that affects your riding environment. It is a never ending, really never relaxed process.

    In the twisties I use a bunch of tactics for four-second+ planning:
    1. I read the terrain, grades, slopes, road pitch/crown/camber, shoudlers (gravel or paved)
    2. I read tree lines or power pole lines, for clues about turn radius, slope, pitch, runoff, sightlines
    3. I evaluate potential sightline issues before I get to the turn, determine if I'll be able to see-through before I get to the entry, shadows, shaded areas
    4. I read the road surface, cracks, tar strips, changes in pavement color, indications for gravel/sand/debris

    Most all of this happens before the entry to the turn, and I certainly make adjustments well before my apex choice and "press-in" point of the turn.

    In traffic I evaluate/assess anything that impacts my riding environment:
    1. Traffic load and motion patterns, which lane is faster or more steady (may be the fast lane)
    2. Watch for any traffic flow path changes due to markings, signs, time of day, traffic load, cross-traffic issues
    3. Look for/evaluate anything that impacts my sightlines, trucks, signs roadside visual blocks ( for me AND for other road users), time of day/sun position in the sky, shadows, bright direct sunlight (for me and other road users)
    4. Watch vehicle trends, cars that hug the lane line, even just vaguely. Quite often vague actions of cars lead to DIRECT actions within seconds or less, watch the tires as they almost never lie

    Big thing is, and I could add so much more, is that effective riding is a highly intensive activity. When you think about the level of brain action, motor skills, evaluation/execution, sensory input/decisions that we do while riding it can easily overwhelm some people into a stupor about riding (like saying its too intense for me) or activate some people into a high level of concentration (like everything slows down and we can "see" it all) that removes all the crap of day to day. That is what riding does for me. I get so deeply involved in the riding, that everything else becomes secondary and unimportant. Probably the main reason I will NEVER consider using a Bluetooth device in my helmet to answer a phone. I feed on the high level of involvement in riding, to the point it relaxes the rest of me.

  7. #22
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    Quote Originally Posted by BCKRIDER View Post
    ... regularly ride blind twisty roads at speeds where you don't have adequate stopping distance or swerving distance. You regard this as "normal speeds," not excessive speed.
    I'm not trying to answer for racer7... however, the key to your question may be the definition of "normal speeds". I define it as "the speed of prevailing traffic". On many of the local curvy roads popular with motorcyclists I do not have 2-4 seconds of road in sight when going "normal speeds". If I were riding riding slow enough to always have that 2-4 seconds of road in sight I'd be at increased risk of someone else running "normal speeds" rear ending me. In my judgement the danger of being rear ended by a cell phone wielding driver not paying attention to the road is greater than the chance that I'll rear end someone else. So far this has proven to be true.

  8. #23
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    The various "second" guides help for sure, but also key to getting the most of the guides is to be constantly active with them. Like I said, my goal is to do a lot of evaluation before I get to situations of sightline issues, but also constantly re-evaluate/adjust the goal with every passing second.

    I wonder if some riders percieve the concept as being in the moment of entering the turn or event. Then certainly, if you are at the entry of your turn, being at the event, and if you can see through to the exit or something else becomes an issue, you better be going slow enough or have enough space/time to adjust, slow, straighten, brake, whatever.

    But a second by second evaluate/adjust technique seems to always be s tep or two ahead of where you'll be. I have ridden with others and they say they just see my bike flowing along the path and curves, no drastic adjustments, no drastic speed changes. That's my goal, a smooth, steady quick pace.

  9. #24
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    Quote Originally Posted by ANDYVH View Post
    The various "second" guides help for sure, but also key to getting the most of the guides is to be constantly active with them. Like I said, my goal is to do a lot of evaluation before I get to situations of sightline issues, but also constantly re-evaluate/adjust the goal with every passing second.

    I wonder if some riders percieve the concept as being in the moment of entering the turn or event. Then certainly, if you are at the entry of your turn, being at the event, and if you can see through to the exit or something else becomes an issue, you better be going slow enough or have enough space/time to adjust, slow, straighten, brake, whatever.

    But a second by second evaluate/adjust technique seems to always be s tep or two ahead of where you'll be. I have ridden with others and they say they just see my bike flowing along the path and curves, no drastic adjustments, no drastic speed changes. That's my goal, a smooth, steady quick pace.
    Your responses (and also those of Racer 7) have been very constructive. I have NO problem believing you are both very experienced and safe (if we can use that term about riding) riders. But the fact remains you haven't answered my secondary question: "In a blind corner - let's make this a two lane road with little traffic - can you stop within your sight distance?" Let's add the fact that you are on a trip and don't know anything about hidden driveways or anything else you cannot see. Does Grodsky's "4-second rule" work for you or not, assuming dry conditions and no visible sand or gravel?

    I'm completely serious in asking your opinion. If as expert riders you say you can stop in 3 seconds on a curve (and have done so,) my hat is off to you. Maybe under the same circumstance less expert folk (such as myself) DO need 4 or more seconds. I DO believe the "seconds count" idea is a good one for blind curves or topping hills as well as the "2-second rule" for following distance under ideal circumstances. My experience is that if you don't apply the 2-second "following distance" rule, you will probably follow too closely.

    Look forward to your thoughtful replies.
    Doug
    1992 K100RS

  10. #25
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    Quote Originally Posted by BCKRider View Post
    But the fact remains you haven't answered my secondary question: "In a blind corner - let's make this a two lane road with little traffic - can you stop within your sight distance?" Let's add the fact that you are on a trip and don't know anything about hidden driveways or anything else you cannot see. Does Grodsky's "4-second rule" work for you or not, assuming dry conditions and no visible sand or gravel?
    On a twisty road, following distances may have nothing to do with choosing a speed. You may not be following another vehicle. From "Motorcycle Roadcraft, the police rider's handbook to better motorcycling":

    Never ride so fast that you cannot stop comfortably on your own side of the road within the distance you can see to be clear.
    and
    The ability to stop on your own side of the road in the distance you can see to be clear determines how fast you can go.

    That is the principle. By the way, the above is an excellent book. You can get it from Amazon. It's from the UK.

    Harry
    2003 R1150RT - Silver

  11. #26
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    Quote Originally Posted by AKsuited View Post
    On a twisty road, following distances may have nothing to do with choosing a speed. You may not be following another vehicle. From "Motorcycle Roadcraft, the police rider's handbook to better motorcycling":

    Never ride so fast that you cannot stop comfortably on your own side of the road within the distance you can see to be clear.
    and
    The ability to stop on your own side of the road in the distance you can see to be clear determines how fast you can go.

    That is the principle. By the way, the above is an excellent book. You can get it from Amazon. It's from the UK.

    Harry
    Thanks for your reply, Harry, and your reference to a book I've heard good things about but don't own. Must order it. I would point out (yes, I know I am becoming a PIA) that neither you nor your quotes makes reference to (4 seconds) visibility. I think quantifying the distance you can see in seconds (given good dry road conditions) would be a valuable tool for many riders. I'm hoping SOMEBODY will either confirm (or not) Grodsky's assertion by actually trying it out. THAT is how you find out if you actually can stop within your sight distance.

    My comment on following distance had nothing to do with the above. Just another instance where counting seconds can provide a reality check which may keep you out of trouble.
    Doug
    1992 K100RS

  12. #27
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    Lets try it this way: 2-lane back road with moderate to tight turns, twisties if you will. Posted speed in general is 55 mph with many turns posted at 30 to 45 mph. Turn speeds as posted are determined to minimize lateral G-force for all vehicles legal to operate on the road, from cycles to large trucks. Turn speeds are posted to also account for visibility issues (or lack thereof). But most of us feel that for a cycle with a decent rider, the posted speeds for turns are easily taken at 10 to 15 mph higher speed just because the bike itself is more manueverable.

    So given adequate sightlines before the turn, at the turn entry and through to the turn exit, turn speeds 10 to 15 mph over the recommended posted speed are actually quite easy and safely doable. IF there is nothing indicated before gettting to the turn, or before the turn entry, that indicate you should adjust your speed lower. For ALL turns, slow in/fast out is a reasonable overall guide. Fast in makes for a LOT of "vynil pucker" moments, with little or no recovery options.

    But blind turns are something unique, for whatever reason that makes them "blind": heavy vegetation, old farm buildings on road edges, fences, rock walls, no shoulders, 180 degree turns, many factors classify blind turns because of limited sightlines. If you can't see through the turn at the very least, to your perceived turn apex (you DID determine your apex before you even GOT to the turn right?) then the turn is a "blind" turn and a safe approach is still slow-in/fast-out:
    1. set up for a wide entry point near to the outside third of the lane: far right edge for a left-hander, near the center for a right hander (but be aware of other vehicles anytime you're close to the centerline),
    2. slow BEFORE the turn, downshift to a gear that actually gives very good engine braking and one that gives you good strong drive our of the turn. In other words, a lower gear that brings the engine revs up. Reg Pridmore says most riders take turns in way too high a gear and "lug" the bike through the turn. Now off the brakes and stabilize the engine speed to be steady before the turn entry,
    3. Go straight into the turn deep, as you approach the late apex you chose in setting up the turn,
    4. By the time you have reached your chosen apex, you should be able to see to the turn exit, you are off the brakes, and have a stable bike in a gear ready to power out through the turn.
    5. PRESS firm and assertive on the "inside" grip to quickly initiate the lean angle needed for the turn, and appliy steady to roll-on throttle to maintain steady loading of the contact patches of the tires.

    All that works great IF there is nothing in the turn to cause you to quickly alter speed, position, attitude. What we also have to take into account is our "out option", meaning do we have runoff available? Shoulder width? Paved shoulders? Curbs? Gravel? Rock wall? The idea being, with your speed down, geared down, ready on the brakes just to the turn entry, you look through the turn and for whatever reason it can't happen. Then you must be able to quickly straight line slow (hard) or stop. That's where the slow of Slow-in/Fast-out really applies. Your out-option is another factor of turn setup before you get there.

    Back to our tight blind turn, left turn, posted at 35mph, no sightline through the turn, wide shoulder (in this case): so slow to 35, downshifting to 2nd gear, steady your speed before the entry, set up for the right third of the lane, at the entry look into the turn, see that the exit is covered in gravel from a dump truck that had passed through the other way. Turn option is out, now its all straight line quick/hard braking, either to a complete stop or slowed enough to alter the line through the turn to do it mostly upright. Even at 35 mph, a quick hard straightline stop will take about 40 feet to do safely. But once you are in braking mode look straight ahead and focus on braking control and where you'll stop. Did you plan for that much runoff in your out-option? Do you have to the option to very briefly straighten up/brake hard/off brakes/press in to your new line and complete a new path? LOTS to think of.

    Point is, slow-in/fast-out is a method for most turns, and more applicable to blind turns. If your "out-option" is further limited by lack of shoulder or run-off room, then the slow-in is slower yet, and in a lower gear. But it is all a VERY active mentally intensive process, most of it done BEFORE the turn. What catches most riders is the complacent riding attitude of accepting whatever comes once they're on top of it, which is FAR too late to apply much of anything other than a panic reaction, which is usually over-braking and dumping the bike: the "hadda lay er down" response. Safe twisties riding requires a LOT of mental activity, and physical ability. Again, what I think catches a LOT of riders is they arrive to the event unprepared, with no skills, no out-options, and panic insues. Crash.
    Last edited by ANDYVH; 05-06-2013 at 10:00 PM.

  13. #28
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    Quote Originally Posted by BCKRider View Post
    I would point out (yes, I know I am becoming a PIA) that neither you nor your quotes makes reference to (4 seconds) visibility.
    For what it's worth, 2 seconds was the standard following distance called for by reputable safety organizations. Of course, that's an honest "one-one-thousand, two-one-thousand" two seconds. For many years I've evaluated my following distance by using poles or delineators, and I've also used that to check the following distance of the vehicle behind me. Lately, I believe safety people have recommended bumping that 2 seconds up to 3 seconds. I believe 2 seconds is adequate under most circumstances, while 3 seconds or more would be wise in heavy rain or snow. A following distance of 4 seconds on dry pavement is in my opinion more than adequate.

    Harry
    2003 R1150RT - Silver

  14. #29
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    I agree. For me, it took some years of riding and consistently checking my following distance to the 2-second count method till I finally got a "feel" for the distance. It is effective for most riding, but should be adjusted to 3 to 4 seconds when conditions warrant. But its a constant effort to maintain when other road users barge into your space cushion. But it makes a huge difference in risk reduction. Not to mention makes your ride much more comfortable.

    Oh, and in the MSF cirriculum, the guides for distances are:
    2-second; minimum following distance you should always try to maintain.
    4-second; recommended whenever possible, certainly for any lower traction instances or for night riding. Also known as the "immediate path of travel" time zone, referring to anything that will have to dealt with very soon.
    12-second; that is your search/scan zone, looking for anything that may eventually come into your immediate path of travel zone. At 70 mph, this means you are scanning out around you (mostly straight ahead) 1,232 feet. That's easier understood as a quarter mile.

    As to the 4-second rule as you ask about for corners, consider that 35 mph = 51.3 feet per second, so in a turn you would be searching ahead 205 feet, almost 3/4 the length of a football field.
    60 mph = 88 feet per second, so in a turn you would be searching 352 feet, 52 feet longer than a football field.

    Point is, ALWAYS be looking far ahead, scan/search ahead as you go. Its constant and ever updating every second. That's survival.
    Last edited by ANDYVH; 05-08-2013 at 03:55 AM.

  15. #30
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    Quote Originally Posted by ANDYVH View Post
    Lets try it this way: 2-lane back road with moderate to tight turns, twisties if you will. Posted speed in general is 55 mph with many turns posted at 30 to 45 mph. Turn speeds as posted are determined to minimize lateral G-force for all vehicles legal to operate on the road, from cycles to large trucks. Turn speeds are posted to also account for visibility issues (or lack thereof). But most of us feel that for a cycle with a decent rider, the posted speeds for turns are easily taken at 10 to 15 mph higher speed just because the bike itself is more manueverable.

    So given adequate sightlines before the turn, at the turn entry and through to the turn exit, turn speeds 10 to 15 mph over the recommended posted speed are actually quite easy and safely doable. IF there is nothing indicated before gettting to the turn, or before the turn entry, that indicate you should adjust your speed lower. For ALL turns, slow in/fast out is a reasonable overall guide. Fast in makes for a LOT of "vynil pucker" moments, with little or no recovery options.

    But blind turns are something unique, for whatever reason that makes them "blind": heavy vegetation, old farm buildings on road edges, fences, rock walls, no shoulders, 180 degree turns, many factors classify blind turns because of limited sightlines. If you can't see through the turn at the very least, to your perceived turn apex (you DID determine your apex before you even GOT to the turn right?) then the turn is a "blind" turn and a safe approach is still slow-in/fast-out:
    1. set up for a wide entry point near to the outside third of the lane: far right edge for a left-hander, near the center for a right hander (but be aware of other vehicles anytime you're close to the centerline),
    2. slow BEFORE the turn, downshift to a gear that actually gives very good engine braking and one that gives you good strong drive our of the turn. In other words, a lower gear that brings the engine revs up. Reg Pridmore says most riders take turns in way too high a gear and "lug" the bike through the turn. Now off the brakes and stabilize the engine speed to be steady before the turn entry,
    3. Go straight into the turn deep, as you approach the late apex you chose in setting up the turn,
    4. By the time you have reached your chosen apex, you should be able to see to the turn exit, you are off the brakes, and have a stable bike in a gear ready to power out through the turn.
    5. PRESS firm and assertive on the "inside" grip to quickly initiate the lean angle needed for the turn, and appliy steady to roll-on throttle to maintain steady loading of the contact patches of the tires.

    All that works great IF there is nothing in the turn to cause you to quickly alter speed, position, attitude. What we also have to take into account is our "out option", meaning do we have runoff available? Shoulder width? Paved shoulders? Curbs? Gravel? Rock wall? The idea being, with your speed down, geared down, ready on the brakes just to the turn entry, you look through the turn and for whatever reason it can't happen. Then you must be able to quickly straight line slow (hard) or stop. That's where the slow of Slow-in/Fast-out really applies. Your out-option is another factor of turn setup before you get there.

    Back to our tight blind turn, left turn, posted at 35mph, no sightline through the turn, wide shoulder (in this case): so slow to 35, downshifting to 2nd gear, steady your speed before the entry, set up for the right third of the lane, at the entry look into the turn, see that the exit is covered in gravel from a dump truck that had passed through the other way. Turn option is out, now its all straight line quick/hard braking, either to a complete stop or slowed enough to alter the line through the turn to do it mostly upright. Even at 35 mph, a quick hard straightline stop will take about 40 feet to do safely. But once you are in braking mode look straight ahead and focus on braking control and where you'll stop. Did you plan for that much runoff in your out-option? Do you have to the option to very briefly straighten up/brake hard/off brakes/press in to your new line and complete a new path? LOTS to think of.

    Point is, slow-in/fast-out is a method for most turns, and more applicable to blind turns. If your "out-option" is further limited by lack of shoulder or run-off room, then the slow-in is slower yet, and in a lower gear. But it is all a VERY active mentally intensive process, most of it done BEFORE the turn. What catches most riders is the complacent riding attitude of accepting whatever comes once they're on top of it, which is FAR too late to apply much of anything other than a panic reaction, which is usually over-braking and dumping the bike: the "hadda lay er down" response. Safe twisties riding requires a LOT of mental activity, and physical ability. Again, what I think catches a LOT of riders is they arrive to the event unprepared, with no skills, no out-options, and panic insues. Crash.
    ANDYVH, you always have something valuable to contribute about safety issues, and I always seem to have another question or opinion. Hopefully, we are making the readers, if not contributors, a little safer. This reply will refer to the six paragraphs above.

    1. I know a number of riders who figure they can DOUBLE the "slow to" speed sign and take pride in doing so. No doubt they can if surface problems, over the line traffic, or an obstacle out of view don't rear up to bite them. I use those advisory speeds as a gear selection tool, rolling off the throttle and dropping a gear or two, and seldom braking before a curve. But I am down to my entry speed with the engine in a power band which can slow me further or accelerate. I would like to say I also have two fingers over the front brake for that emergency stop, but I don't. Something to work on.

    2. Complete agreement.

    3. The only way to pick an apex on a new road is to see the exit to the turn. On a left bend, you stay as far right to your lane as safe with a steady throttle until you see the point where you can accelerate and maybe kiss that center line and move to the right. On right bends you want to stay close to the center line as possible for visibility issues and be slow enough that you can swerve to the right for an oncoming vehicle over in your lane without going off the road.

    4. Yes.

    5. Yes.

    6. Yes, but I AM STILL WAITING for someone to substantiate (or refute) Grodsky's "four second rule" on blind corners. I would submit that counting seconds (for whatever reasons) is a tool easily available to all of us, whether in our car or on our bike. I would also submit almost all of us are awful at judging distance when in a moving vehicle. Seconds (not car lengths, or feet or meters) should be what is taught and what experienced drivers/ riders talk about. That is the subject I'm still broaching.
    Doug
    1992 K100RS

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