A team of Japanese scientists have managed to find an explanation for the known "invisible jams". These are formed even when no incident has occurred on the road, like an accident, collision, police driving, irregular crossing, traffic lights, etc. This phenomenon is known as “invisible jam” In English it is called “jamiton“, which comes from the conjunction of "jam" and "soliton" (a type of wave that spreads without changing its shape).
There isn’t anyone who hasn’t suffered a traffic jam in his life. In fact, there are people who have to live with them every day. Worst of all is when in addition to the usual jam you stumble upon, you find even more unusual situations. Why did this new traffic jam originate? And the final shot comes when finally all vehicles are finally circulating, the jam disappears, but you never knew why this jam happened in the first place.
Why do jams form?
According to numerous studies, a highway lane capacity is approximately 2,200 vehicles per hour, as long as they all circulate at a constant speed. This would theoretically be the maximum limit. Now, at 1700 vehicles per hour we could start encountering problems. If there’s more than this amount of vehicles traveling in a same lane, the speed march can be impaired by any distraction by a driver or any other similar circumstance. Let’s see what these possible causes would be:
Number of lanes may be reduced
It is one of the main causes of traffic jams when there’s a high vehicle circulation. Every time a lane is incorporated or lost, circulations starts getting complicated.
The accordion effect
This phenomenon occurs when there is a small braking that makes the cars that come behind have to slow down. On average, each car takes a second to start up later than the car in front of it. The third car in a traffic jam will start 2 seconds later, the fifth 4 seconds, etc. So if a small traffic jam occurs with 120 cars closed to each other (which will occupy a little less than one kilometer), the last one will start about 2 minutes later. Imagine this in a normal traffic jam where there can easily be more than 5 km of traffic jam, we would be talking about 10 minutes minimum to get out of it.
Distractions for drivers
This is one of the most difficult causes to avoid and prevent. There are many drivers who, at any given moment, get distracted and have to slow down their vehicle. Among these distractions, the most common is mobile phone use, smoking while driving or slowing down to look at an accident.
There are many people who think they are in a Formula One race. They drive based on accelerations, braking, lane changes. These type of drivers during traffic jam only can delay decongestion, because they are the causing an accordion effect.
Their state, as well as their design, can greatly influence traffic jams. On roads in bad condition, with bumps and furrows, braking and sudden turns are more frequent, which cause drivers to slow down and retentions are formed. It’s also relevant when a road has many roundabouts, traffic lights, intersections, etc. We can also include the weather. Rainy or foggy days make circulation very difficult due to poor visibility range. As well as the very low temperatures that may cause ice sheets to appear.
Type of vehicles circulating
If there’s a higher number of heavy vehicles, trucks and buses, more likely to jam. Since these types of vehicles tend to move slower, causing more lane changes and braking among other drivers.
Japanese jam training experiment
In this experiment, Japanese scientists put 22 vehicles on the road. They did it circulating at a constant speed of 30 kilometers per hour, tracing a circle of 230 meters. While all the cars go at the same speed, the circulation is fluid and there is no problem.
At one point in the test, one of the vehicles brakes slightly. This causes the rest of the vehicles to brake as well, causing an immediate accordion effect.
How to avoid traffic jams
Seeing how the traffic jams happen, the truth is that the only possible solution is to have fewer cars circulating on our roads. Since although all of them circulated at a constant speed and will keep a safety distance with other cars, still, any of the causes that we have described previously are always possible and waiting to happen. There are exits, incorporations, lane changes or oversights, which can reduce speed on some drivers, creating an accordion effect.
Now that you know this, try to make a more frequent use of public transportation. If you have no choice but to drive in a car, always keep a safe distance, do not make sudden maneuvers and do not get distracted by your phone, radio or cigarette.