Transporte urbano

hen this subject is mentioned everybody thinks about buses, trams and rail, which of course are the bone system of mass transportation in cities. However, information of how easily people move in walking the city it is also very important and for this reason the transportation issue has to be addressed holistically considering mass transportation and facilities for people to move, and the same happens of course with transportation of goods. In old times there was little need for people transportation because cities were small, people used horses and many were too poor to afford horse driven buses. Streets were irregular, with twisted roads, alleys and very narrow passages, which facilitated walking from one site to another. The city grew at random, with no reason for the twisted streets other than the convenience of a group of neighbours to go from one place to others with the minimum effort that is with the least walking.

Many cities in Europe still keep this layout of streets which usually is located in part of the downtown area. Examples abound in cities like Paris , Madrid , Tallinn , Prague , Istanbul , and many others. Figure 1 shows a map of the central part of Seville about ten centuries ago, albeit much of it is still conserved in the same way; it is interesting to see how this pattern is a close replication of that pattern caused by draught on the bed of a river, which seems to corroborate the theory that original settlements were at random, since a grid of streets and avenues intersecting at a right angle and forming a uniform grid, came only during the last 500 years.

Examples can be found in every Latin America city built by the Spaniards. For instance, examine a map of downtown Cordoba , Argentina , founded in 1573. See Figure 3, and take into account that diagonals were only built at the turn of the XIX century. From the point of view of transportation the rectangular grid system is a very efficient one because, according to the geometrical principle that the straight line is the shortest path between two points, allows the fast displacement of surface transportation, such as buses and trams.

In old times, people, merchants and horse carriages, shared streets and open spaces. People gathered there as a meeting place to chat, to shop and to see streets entertainers like jugglers and acrobats. This condition has changed in the last centuries, especially in the XX century when streets lost their pedestrian conditions yielding to motorized traffic. In reality streets are for people, not for vehicles, and fortunately, in the last four decades, there has been a worldwide movement to try to give back the streets to people.

Because of this, pedestrian thoroughfares are in every city of the world starting at a certain size. Figure 3 shows these pedestrian thoroughfares in darker colour. At the same time, observe in Figure 4 the green fine and short lines which represent galleries and malls that join adjacent streets, packed with shops, bar, restaurants, movie theatres, etc., and it appears to be a modern answer of those old streets and places where people gathered. Other than the improvement of social life, these galleries link different streets and in so doing reducing the distance a person has to walk to go from one point to other.

In some cities, mainly Montreal and Toronto , there exist a true underground city which is connected by the metro stations (in Montreal ) allowing people to walk the downtown area under a roof. Of course, especially in the case of Montreal , the main reason for this lay out is the harsh winter with freezing temperatures on the surface. In some cases these galleries act as truly transfer points between the metro, local and long distance passenger trains, and have access to hotels, theatres, large department stores, convention centres, public buildings, etc. In other words, it appears that people is regaining their right to use the streets as before.

Figure 1 - City of Sevilla circa 11 th Century

Figure 2 - Bed of a river with soil fractures caused by draught

Figure 3 - Central area (macrocentre) of the city of Cordoba ( Argentina )

Figure 4 - City of Cordoba ( Argentina ) detail of the microcenter

However, even if citizens own the streets of their cities is not realistic to think that they must be free of motorized traffic, especially in downtown, and allowing only pedestrian traffic, because it is necessary to remember that nowadays, because commercial, academic and industrial activities in the city, streets must be shared by people, buses and trolleybuses, trams, cars, delivery trucks, and bikes, and all of them on the same space. It is really and engineering marvel to plan a city in such a way that all of these users can displace without difficulties, and making a multiple and very effective use of land space.

There are different solutions to tackle this problem.

1. One of them consists in building dedicated roads for buses with stations separated at a certain distance. This is the policy followed by the cities of:

•  Ottawa , Canada , ‘Transit way'
•  Curitiba , Brazil , ‘Integrated Transport Network'
•  San Paulo, Brazil, ‘San Paulo Rapid'
•  México D.F., México, ‘Metrobus'
•  Los Angeles, USA, ‘Orange Line'
•  Cleveland, USA, ‘Euclid Corridor'
•  Guayaquil, Ecuador , ‘Metrovía'
•  Pereira, Colombia, ‘Megabus'
•  Santiago, Chile, ‘Transantiago'

Some of these systems have large parking lots at the main stations where patrons can park free when boarding a transit.

2. Many cities around the world, but mainly in Europe use modern trams that mix with traffic without problems. Lately, Buenos Aires has joined this trend

•  Other alternative which could coincide with the above is the construction of large transfer stations where buses from different lines intersect, facilitating transfer of passengers. Examples are in:
•  Ottawa , where some of these transfer stations are located underground of large shopping centres and connect with the railway station.
•  Frankfurt , where buses, trams, local and long distance trains connect in one place. Same happens in Brussels , Munich and Salzburg .
•  Berlin , Paris , Madrid , London , repeat the same scheme and some of them with direct connection to the airport as in London , Madrid , Stockholm , Seoul , Hong Kong, Shanghai , etc.

4. Bus lines following a circular path usually around downtown, is other good option. In large cities there is more than one of these circular routes. Examples are:

•  The surface transit system, mainly trams that travel along the Ring Boulevard in Vienna .
•  The same system is advantageously applied in underground metro lines, and in so doing connecting with all of other lines of the system. The cities of Madrid , Glasgow and Beijing follow this system.

5. Naturally, the transportation system is somehow intimately linked with the city topography. As an example we can mention Vancouver , where the city is located on both shores of a sea inlet. Even if there are two bridges than connect both shores, the trip takes a long time. For that reason and following the principle of the straight line, a ferry passenger service connects in a few minutes both terminals shortening the trip and carrying a lot of passengers in each trip. This city has one of the most efficient transfer stations of the world for in a single station converge the metro, buses, trolley buses, local trains and ferries.

6. Construction of bikeways connecting different parts of the city. Some Latin American cities have more than 200 km of bikeways, and in some North American cities, buses are equipped with racks to carry bikes.

7. An old rail system which consists in elevated trains running along avenues is doing some sort of comeback as can be seen in the cities of Kuala Lumpur , Bangkok , Vancouver and Lima.

8. There is also other aerial system formed by monorails that travel in the downtown area. Seattle and Sydney offer examples of this efficient and not contaminant system.

9. In those places where there is a short distance between two points but very steeply, a good solution is the cable car and it is found in many cities around the world as in Bahia and Rio de Janeiro , Vilnius , Paris , and Zagreb . They offer a direct and straight connection and avoid a twisted and long trip using a road. Hong Kong also has this system and moving ramps to ascend not too steep slopes.

10. Of course, the personal car is in most cities the main way of transportation. Needless to say, its use should be discouraged for many reasons, the most important being the air contamination they produce, and the other is traffic jams. The best solution appears to be parking the car in dedicated parking lots and boarding the bus or the train. Probably the ‘best' example of intensive car use for urban and periurban travel is Los Angeles, however, highways are so clogged that nowadays it is a disadvantage to drive a car, especially when it transports only the driver. A good option, also existent in the city is to allow cars with more than one passenger to use a dedicated lane of the highway.

One aspect that is intimately linked with transportation is urban connectivity, in the sense that all districts of the city should be interconnected without the need, as is usual in many places, to go through downtown. This involve the construction of tunnels or viaducts (to avoid rail tracks), bridges (to go over rivers and deep gorges), roundabouts (at many intersections), as well as traffic distributors.

Finally, it is necessary to think the transportation system of the city in conjunction with the transportation city of the region. Usually a rapid road linking the different cities that form the metropolitan area is a good solution. In large cities, the central city must be as in the centre of a spider web, with radial roads connecting the city with its suburbs and then these suburbs connected among them with secondary links.