Freitag, 7. Juli 2017

The Slow Tires

Once there was a man with a car. On this car he had 4 tires.
As the car is a modern one it has a nice board computer which collects many measurements. One is the rotation per minute of the tires.
One day it took more time for the man to get home than usually. So he decided to check his car's computer for any values which could lead to that delay.
After some minutes searching he made an alarming observation: This days average rotations per minute of the tires were much lower than the values of the day before. So he did a quick check if he found some errors in the computers log, but as everything seemed ok he was puzzled.
The shop where he bought the tires was still open and so he went there and ask a technician to check if the tires were ok, as they were slower today than yesterday. A technician checked correct pressure and even made sure the tire balancing was ok.
But there still was the lower rotation per minute for this day, and no explanation.
Next to the tire retailer there was a garage, which owner was friends with the technician of the tire shop. He agreed to check the car, if there was anything he could find about this days slow tires. But there wasn't anything. No errors, motor control all ok, the shock absorbers were even less utilised this day than the previous day.
During the investigation our man tried to remember if anything has been different to the previous day. He remembered some things: the day before he had lunch, which he skipped on this day to get home early. And even the coke in the cup holder was empty. So in theory the car should even be lighter than the day before. He told the two engineers about his memories, but they didn't care about some decagram changes in weight. At least the mechanic confirmed the average rotation was slower on this day. It matched the slower rotation in the gearbox, something which was not available for a customer in the cars memory. So the measurement was correct.
All three men were puzzled. But the mechanic had a friend in highway administration who had access to the highways measurements. Maybe there wa a technical issue there?
But the highway was in good shape, quite similar as the day before. Nothing was broken, all signs working ok. No accident reported. Asphalt temperature was slightly higher than the day before, but perfect within the tires comfort zone. The mechanic got one more information from his friend: Highway administration was more pleased about this day, as the utilisation was higher when the man went home on this day compared to his yesterdays commute, but still within acceptable boundaries to avoid heavy complains.
Now the men had checked virtually everything which came to their mind: tires, many components of the car, highway. Everything fine, no errors or accidents, totally within acceptable boundaries.
Big data, big confusion.
The tire retailer grabbed his smartphone in frustration to check new gossip in the app of his preferred local radio station. By accident he hit the traffic tab with his calloused fingers and saw a nice histogram of the traffic in highway segments around the city. At the travel time of our man on this day there were much more cars in his highway segment than at the day before. He showed this nice graph to the others and slowly it all made sense:
They all know from own experience, more cars on the highway will lead to slower average speed at some filling level. Traffic is still smooth but the individual just can't do high speed anymore, regardless of legal limitations or police.
Of course at this point the utilization increases, as from the highway administration perspective, there are more tires on the road now. Even when each one rotates slightly slower, the total sum of all of them is higher than a single car at highest speed ever could create.
Our man just could not drive as fast as yesterday as many other cars were in his way.
And the tires could not rotate faster for exactly that reason.
With all this insight our mechanic once again called his friend and asked him if he know a way to improve the situation. The answer was simple:
Build a dedicated highway for you. Never share it with anyone. Not even with your best friend. IT will go perfect most of the time. But the one day you want to do the surprise birthday party, exactly this friend will be on the highway ahead of you and block all your best intended efforts.

I'm sorry for all who love the english language - if you want to translate this to proper english, please do so and inform me, I'll remove this content and link to yours!