# Clustering of Events, from anonymous

May 27, 2015 |

Here is an article from the world of transport engineering. It's not too much of a stretch to apply something similar to observations and timings of magnitudes in financial markets:

Maybe you've waited at a bus stop for longer than usual, and your bus finally shows up. And then, immediately after, a second bus on the same route pulls up right behind. What gives? Why can't they stay evenly spaced to improve everyone's waiting time? Lewis Lehe provides an explanation in a small interactive game.

Two buses travel along the same route, starting off in opposite positions. They make stops and pick up passengers right on schedule. But then add in your own small delays, and you see bunching relatively quickly. It really doesn't take much to throw off the equal spacing…..'

## Jim Sogi writes:

Watch the ocean for a while, or the beach. Random waves cluster to form set waves, larger than the rest, or rogue waves, which can be magnitudes greater than the average. I believe this is a function of randomness or alternately pattern formation from simple binary functions a la Wolfram.

Here's some good information about Three Phase Traffic Theory.

## Jim Sogi writes:

When I go to the US Mainland and drive the big freeways for long distances, I try to drive about 2 or 3 miles per hour slower than traffic.  Most try to drive as fast as they can and bump up against slower traffic groups, and results in waves of clusters of cars.  It's more effort and emotional cost to try drive fast and requires more attention to try pass, notice and avoid slower cars, and cars next door.  Driving a bit slower requires less attention, less stress as you set you speed, and allow other drivers to pass, avoids coming up on slower traffic, and allows you to drive in the spaces between clusters, the "lulls" so to speak. I'm not in a rush and find it more relaxing and you can see the clusters in the distance, and adjust to drive between them. In large urban areas, the clusters tend to be time of day (rush hours) and location oriented, except for accidents.

In markets, vol clusters and it's good to be aware of the lulls and clusters, the timing of them, the length of the lulls.  It's like the lulls and sets in surfing. Trading also seems to cluster around the rounds, and time of day (arc sine).

In playing and composing music, it's important to leave "space" in the music, where there are fewer notes to allow emotional development.

## Jonathan Bower writes:

Mr. Sogi makes some very good observations. I drive 150 miles round trip every day for work. I see people in such a rush to "slow down" when they inevitably meet slower traffic (or jam). Maintaining a high average speed is much more important in determining length of drive (and better on gas). There is also a strong behavior bias to get in the left lane that frequently staying right, particularly in heavy stop and go, is frequently and consistently optimal.

## Jim Wildman writes:

And mathematically, except on long, open road drives, speeding won't save you signification time even assuming you succeed in increasing your average speed.

You can't save 5 minutes on the typical 20 minute commute by speeding. You can if you are willing (and able) to run stop signs and stoplights.

I used to drive from East Texas (Longview area) into Dallas every day (about 115 miles). It was my observation that most radical speeding (10 MPH over) occurred where it would do the least good. Very few drivers speed in the truly rural areas, but once you get into the more potentially congested areas, the number of speeders goes up.

I've found that the frequency of speeding is inversely proportional to the density of police cars on the side of the road. The result is that you have lots of speeding going on on the interstates, punctuated by islands of drivers going at the stated speed limit. I don't know that the state makes much off of speeding tickets in this setting; I do know that it presents a nice the opportunity for accidents as cars slow down and then speed up. Twice, I've seen cars flip in the course of trying to avoid an accident while slowing down—once was just out of range of a radar gun.

## Stefan Martinek writes:

I found that a good solution is to reverse the time zone. I had one period when I was living in the US time zone while in Europe. It is always good to avoid crowds. Gyms are also nice and empty around midnight. No clustering.

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