Urban traffic: has become a serious problem

1990/05/01 Aizpurua Sarasola, Joxerra Iturria: Elhuyar aldizkaria

• Garraioak
• Ingurumena

With this title we do not believe that we say anything more about the world. We know perfectly the access to Bilbao, from Errenteria to Donostia, etc. what happens. If in Euskal Herria this problem is already serious, go to Paris or Madrid; the only word I have found to describe what happens in the country has been “paralysis”.

30 years ago, the number of cars was not very high, so access to large cities was not affected. As the number of cars increased, the discomfort also increased. With the installation of traffic lights in the streets, in the surroundings of the large city, numerous highways, highways and ribs were carried out in order to reduce urban traffic. But the tranquility did not last too long, since the production and sale of cars have had a geometric growth.

Therefore, the need for a regulation system was fully justified. There are many efforts made and in development. In the concept of regulation, those actions of a dynamic nature are considered especially. That is, the state of the roads and infrastructure is maintained. These static factors will not be the subject of study but of dynamic factors that affect them. For example, the obstructions or jams that occur between 7 and 9 in the morning or between 5 and 8 in the afternoon, or the placement of some traffic lights in green and others in red at crosses, etc. These are the mentioned dynamic factors.

But the word regulation encompasses many factors, it is not the same to regulate a street, a neighborhood or a city. However, there are some common steps.

First, a mathematical model of circulation of the object of study system should be established. This summary expression of traffic will allow to perform simulations. Obtaining this mathematical field is more complicated than expected; it can be said that it is almost science. Although there are different theories, all have a common beginning, that is, the consideration of traffic as physical enomene. In particular it is considered fluid. Therefore, the laws applicable to a fluid are applicable in this case. But this fluid has very special characteristics, since almost all particles should be considered independent.

The simplest traffic equation is:

U = U max (1–K/K max )

where U = flow velocity U max = maximum flow velocity K = concentration of vehicles K max = concentration of vehicles in the obstruction

This function is only valid for a specific point and moment of the road. If you want to study for any time a road, a crossing, a neighborhood or a city, you have to consider more variables. In this way you can get a differential equation as complex as you want.

With this track you get a traffic pattern. In addition, this model would be quite particular, since each geographical place has its own particular conditions. Do not think it is an easy model to get, since there are changing and unbelieving conditions

...

The next step is as difficult as the previous one, that is, knowing the model and improving traffic. Normally, the mathematical model is processed by a computer and traffic control is left under the responsibility of an expert system. We can say that what is known today about traffic control is traffic control, that is, putting green and red traffic lights in an area. However, in some places it is working on other systems, that is, with a microcomputer installed in the car, the orders sent from a control center are received, giving some advice to the driver. For example, in the event of obstructions in the city center, alternative routes or the most appropriate route can be reported at the time to travel.

But traffic control can be carried out in many other ways. The color change of the lights of the traffic lights is usually cyclical, usually a time is given to each color. Traffic lights at a crossroads are usually related, but often the time that is given to each color does not have to do with the existing traffic volume. In addition, the traffic volume varies from hour to hour and if you want to perform proper control, this factor should be taken into account.

In summary and for the future, it is foreseen, on the one hand, that the decisions are made in real time, but, at the same time, the cars that are to be built must have communication capacity with the environment. For this purpose, several projects are being carried out in Europe. For example, DRIVER and Europolis projects aim to regulate traffic and the Prometheus project aims to design a car capable of communicating with the environment.

These are the predictable solutions. They are not magical, but we believe they will help something. And we can also help us. How? ... so with the maximum use of public transport and taking the car in the most necessary, for example.