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# The psychological causes of traffic density waves and a possible way to solve them

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I think the the development of road traffic density waves can prevented.

All annoying road traffic density waves involve stop and go traffic. Basically, when one car on front of you speeds up, your natural reaction is to speed up. When a car on front of you slows down, your natural reaction slow down as well. The simple reason why there are traffic density waves is simply because people are not all speeding up and slowing down at the same time.

If all cars decelerated at the same rate (say 1/6th of Earth's gravity), their relative velocity would remain constant, so cars that were moving faster will continue to move faster, etc. When their velocities would otherwise result in a collision, the faster driver who is behind the slower driver is forced to hit on the brake, and thus have greater deceleration of the other car, eliminating the uniformity of acceleration.

To reduce traffic by traffic density waves, one must reduce the amount of brake use, which requires a change in how it is used, which requires the change of signaling that encourages the use of brakes, that is, spurious gains in speed. I believe the solution lies withint the brake light signaling. Not only should the brake light signals be ON when a driver uses the brake, the brakes should be ON when someone is accelerating too fast. Consider the effects it would have on driving.

Suppose someone speeds up too fast, and its brake lights turn on. Obviously the car is speeding up, not slowing down. As someone who is used to the tried and true method of signaling, you go ahead and copy what that person was doing and speed up too fast as well. All of a sudden, the guy hits on the brakes, and you do the same. While your lights were ON only when you were braking, his lights were ON the entire time from acceleration to deceleration. Not only does he waste gas, but you waste gas. Remember: mass*acceleration*distance = energy. The more you try to beat the flow, the worse it will be on your fuel economy.

Suppose after 1 month of seeing cars that have the brake light that turn ON during periods of high acceleration, while happening to suddenly stop in front of you, you decide that you shouldn't speed up as fast as the person who speeds up with their brake light ON. As a result, when that car finally stops hard, you don't stop nearly as hard, and neither do the cars behind you.

A single car that stops and goes too fast can seed a traffic density wave if others follow that same pattern of behavior. The goal then is to stop that pattern of behavior.

That's my idea.

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Or in other words...

STOP TAILGATING!

If I am in your rear-view mirror, you should not be in the fast lane, ;)

Buffy

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Hi Kmarinas86,

I think the the development of road traffic density waves can prevented.

There is a program that's used to model some of these things. My uncle worked for the NSW Regional Transport authority and they did these types of things manually (traffic light switching systems etc) in the past.

Projects

Don't mistake it for the other Echelon program.

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I think the the development of road traffic density waves can prevented.

All annoying road traffic density waves involve stop and go traffic. Basically, when one car on front of you speeds up, your natural reaction is to speed up. When a car on front of you slows down, your natural reaction slow down as well. The simple reason why there are traffic density waves is simply because people are not all speeding up and slowing down at the same time.

...

That's my idea.

I disagree with these premises as they don't consider intersections, highway ramps, or speed zones as mitigating factors. Besides, I don't want to get rid of the traffic density waves because I drive in the troughs. ;)

As a bonus, here's how I get around the traffic engineers' signal activation programming. If I have a red, I completely stop short of the line, set stopped a few seconds (at least 3-5) on top of the sensor, then roll forward a foot, then stop completely, & repeat. Each movement is counted as another car. I trip signals all the time this way and especially enjoy activating left-turn signals out of sequence. :D

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Flux = velocity * linear density.

Keeping a given value of flux requires the other two being inversely proportional. Try training the average driver this way, especially while they're thinking of what to get their daughter for her birthday. The average driver's change in acceleration will always be delayed compared to the previous car, as well as not exactly adjusted. Typically people will start slowing later and end up slowing more, then start regaining speed later and then strive to keep up.

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