Texas Cushman Club Inc.
UNDERSTANDING THE RUBBER-BAND EFFECT
Impact of speed change of the Leader
After I did a study of the Rubber-Band or Yo-yo effect in group ridding I have a much better understanding of the reasons for problems we encounter on most group rides. In the pre-ride meeting, we always emphasis, that we should attempt to follow the 2 second rule. That is maintaining a two second space between you and the rider in your track (directly in front of you) and a 1 second space between the rider on your right or left. Riders in a group find that they must accelerate after a stop or a turn has been encountered and then all of a sudden they find it necessary to brake to avoid over running the scooter ahead. A good leader can minimize this effect but it would be good for all riders to understand what is happening and anticipate what they should do to keep the formation as tight as possible.
Reaction time for a motorcyclist when confronted with an unexpected threat is, on average, about one second and ½ second for anticipated moves. When a group of riders change speeds very gradually, however, it usually takes two or three seconds for a rider to recognize this and begin to change his speed to maintain his position in the group. This doesn’t sound like much time, but experienced group riders manage their risks reasonably well with a minimum one-second interval between each bike and a minimum two-second interval between bikes that are traveling in the same track. The study pointed out that when the group has more than six bikes in it, gradual changes in speed within the group can become tricky. When a Lead Bike begins to accelerate, the second bike doesn’t instantly start to travel at the faster rate. Instead, a gap grows between them while the second bike is reacting -- and it continues to grow until the second bike is fully up to the increased, stable speed of the Lead Bike. Now we have a situation where the space interval has changed due to the reaction time if the leader does not accelerate slowly. Clearly, once the speeds are the same, the gap will remain the same size. However, since most groups prefer to keep a one-second minimum interval between bikes (two seconds between bikes in the same track), the new gap caused by the Lead Bike’s acceleration may be larger than is desired. When this occurs, the second bike must go faster than the first one for a brief time in order to “catch up.” I have heard many leaders say they never got over 30 mph when someone complained they had to run 50 mph (sometime faster) to catch up and maintain the 2 second interval and when he did catch up he had to slam on the brakes to avoid over running the scooter ahead. What happened? The leader did not take into account he/she should have accelerated at a much slower rate until the formation was all moving at the same speed and then slowly accelerate to the announced speed in order to minimize the rubber band effect. The study was done using highway speeds but the same effect applies equally to our ridding speed just not as dynamic. Here is what the motorcycle study said, “If we assume that the Lead Bike speeds up from 60 to 70 mph over a period of two seconds, the second bike will have to ride at 75 mph for two seconds (after his reaction time passes) in order to close the gap. Then he will take another one second to decelerate back to 70 mph to create a gap of the proper size. If there were only two bikes in the group, this example is easy to follow. But when the group is larger, and the bikes involved are riding further back in the pack, the “rubber band” effect can be especially dangerous to all bikes from the middle of the group to the Drag Bike.” To better understand the example, we could say that the speed gap and speed interval multiplies with each successive scooter back to the drag scooter. And that fellow scooter rider is why we get such large gaps in our formations. The study went on to say that groups should never exceed 6 to 8 bikes. I am not too sure I agree with that but I do agree that when we do a ride that has 100 or more scooters in one formation it is just flat dangerous and very difficult to control. All that said, we can all pat each other on the shoulder and say how good a job we did keeping together, given all that can go wrong.
Reducing the Problem
1. Break the ride up into smaller groups.
Great idea if we have enough helpers such as Leaders, Guides and other support people.
2. Lead scooter accelerates at more gradual rate.
All leaders should understand and practice.
3. All riders watch farther ahead than just the bike immediately in front of them in order to notice and to react quicker to changes in speed.
4. All slower scooters should be at the front of the ride with faster scooter in the back.
5. Communication during the ride between the lead scooter and the drag scooter and chase vehicle.*
In Abilene we will try a couple of different approaches to the large ride but these will not work if you do not understand the way the ride will happen. Don’t miss the General Safety Meeting scheduled at the beginning of the meet and if you miss the meeting for good reason make sure you contact me to get the information.
West Texas can be hot but not uncomfortable as the humidity can and usually is low. With that said I would suggest that you give some prior thought to making sure you have a way to carry a bottle of water with you when you ride. We will have water available but to be on the safe side give consideration to having your own available when you ride.
Look forward to seeing all in Abilene and thanks to all you contacted me since the last article.
Ride Safe, Richard
So far we have not been able to come up with a scooter to scooter communication system that will work for us. The best idea yet has been cell phones with blue tooth capabilities. Problem with the cell phones are wind noise and no service areas where we ride. So if you have a possible solution, contact me.
DANGERS OF LEFT TURNS
Vehicles Making Left Hand Turns
The single most dangerous situation for motorcyclists occurs when cars are making left-hand turns. These collisions account for 42% of all accidents involving a motorcycle and car. Usually, the turning car strikes the motorcycle when the motorcycle is going straight through an intersection. In this scenario we need to explore what the motorcyclist can do to maximize his/her safety.
Just for grins assume you’re invisible, because to a lot of drivers, you are. Never make a move based on the assumption that another driver sees you, even if you think you have just made eye contact. You should never be sure the driver sees you. You can counter such a situation by positioning yourself to be as visible as possible, and by dressing conspicuously. Here is where we are coming from with the move to wear distinctive vest while riding, Make Yourself Visible! Position yourself on the roadway to be as visible as possible, be aware of your surrounding so as to not be hidden. For example , if the situations is an intersection and there are people gathered to your right waiting to cross the street position yourself away from them so you don’t blend into the crowd. If you think the oncoming traffic is going to turn left across your path flash your headlight or blow your horn. After all the, horn is there for such a purpose, not just a little honk to say I to someone you see.
Across Your Path
When it happens, your speed and visibility bears on how well you can perform when a threat arises. The faster you are approaching the threat, the less time you have to recognize it, anticipate what will happen and take appropriate action. And, whether you swerve, brake, or simply pray, it will consume more distance than if you were going slower. In other words, when things go wrong, speed is not likely to be your friend. Just as in the intersection situation, distinctive clothing and anything you can do to attract attention, is helpful. Defensive thinking will be a key here, and in the case of the kamikaze driver who is going to beat you to the crossing point come hell or high water your action will play the most important part of avoiding a collision. Depending on your speed, when the potential hazard is recognized, being in a lower gear, when you have that choice on a Cushman, and ready to brake hard, accelerate away , swerve hard or line up a potential escape route are all considerations. All of the afore mentioned don’t just come naturally. Practice braking hard , using both brakes remembering that your front brake will do more to slow you down than the rear take into account your capabilities and the road condition. Practice swerving at different speeds. Learn to recognize escape routes. Mental preparedness goes a long way here. You must have a plan in place to react to the threat when it presents itself. Turn some of these skills into games that you can play with your local group meets and informally with friends,
The MSF (Motorcycle Safety Foundation) has developed an acronym for the mental process required to anticipate and deal with threats. It’s SIPDE ( pronounced sip-dee), and stands for:
Scan - Constantly scan the environment around you. If you focus on only one thing, like a pedestrian crossing the street, you may miss other hazards like the person getting ready to open their car door next to you.
Identify - As you’re scanning, identify all the potential hazards. “Filter out the noise”, and identify what’s important. Don’t forget to identify potential problems approaching from the rear as well!
Predict - You’ve identified the potential hazards, now predict what the outcomes will be if certain scenarios play out. Focus on the worst case scenarios. You may be able to swerve around a pedestrian, but probably won’t survive tangling with a garbage truck. Prioritize accordingly.
Decide - Decide on a course of action that you would follow, should one of the scenarios you predicted plays out.
Execute - Execute the course of action you
Some Call it SIPDE
The Motorcycle Safety Foundation has developed an acronym for the mental process required to anticipate and deal with threats. It's SIPDE (pronounced sip-dee), and it stands for:
This information was taken from the national motorcycle
information. Richard K.
No matter how many precautions a motorcyclist takes, and no matter how much
skill a rider has, there will inevitably come a time when they have to respond
to an emergency situation. This article will discuss a few possible emergency
situations, and how to react to them.
A motorcycle tire has exactly 100% traction. The things that require portions
out of that 100% are acceleration, braking and turning. What causes a tire to
skid is exceeding that 100%. For example, a rider approaches a curve at 40 miles
per hour. Upon entering the curve the rider realizes he is going to fast to
complete the turn. So he/she squeezes the brakes mid turn to slow down. The
rider has now used more than 100% of the tires traction. Both tires will now
skid out, and the bike and rider slide off the road. What the rider should have
done was slowed down enough before the turn to complete the turn without using
the brakes. However, since the rider was going too fast, they should have
leveled the motorcycle before squeezing the brakes. This would allow more
traction for braking and less for turning. Therefore, the tire would remain
within its allotted 100% traction level. In the same way, a rider should not
over accelerate while turning. The ideal turn is performed as follows. The rider
slows down before the turn enough so that they can slowly accelerate through the
In any situation, the goal is to maintain control of the motorcycle. There are a
few things that can cause a rider to lose control. Obviously, one of those
things would be running into an object or another vehicle. So to avoid doing
this a motorcyclist should master the ability to swerve to avoid obstacles.
Swerving is the same thing as turning, only with a lot more haste. To swerve,
you press down hard on the handlebars in the direction you want to go. Then you
quickly level the motorcycle by releasing pressure on the handlebars. This will
get the bike moving straight again. Finally, you put pressure on the handlebars
in the other direction to move back into place. The amount of pressure placed on
the handlebars will determine how quickly the motorcycle will swerve. It is very
important to not grab the brakes while swerving. Doing so will cause the
motorcycle to skid, and you could easily lose control.
In the unfortunate case that a motorcycle goes into a skid, there are ways for
the rider to correct it without crashing. If the rear tire goes into a skid, the
rider should immediately release pressure off of the rear brake. At the same
time, the rider should make sure and hold the front tire steady and straight.
Doing this should cause the rear tire to snap back into place and continue
rolling. The harder skid to control is a skidding front tire. Once again, this
is because it’s the lead tire and guides the entire motorcycle. A motorcyclist
doesn’t have very much time to react to a skidding front tire before crashing.
If experiencing a front tire skid, the rider should immediately release the
front brake and stand the bike as level as possible. If done quickly enough, the
front tire will begin rolling forward again and the rider can regain control.
Some other emergency situations can occur that are highly unusual such as an
animal running in out in front of your motorcycle. However, knowing how to
control the motorcycle in an emergency can prevent many accidents from
happening. However, the saying goes, “There are two kinds of riders, those who
have crashed in the past… and those who will in the future.” That is why it is
important to always wear proper equipment including a helmet, gloves, long pants