APPLICATION OF THE DESIGN METHOD
To illustrate the design method described, two concrete cases have been elaborated: design of the national network of Hungary and the federal network of the state of Florida. The
following paragraphs present the results of the various design steps.
Hungary: Design of the National Road Network
See also Monigl (2002) and Buckwalter (2001).
Step 1: Hierarchy of Nodes. The first step in the design process is the decision how many (and which) nodes (cities) will have to be incorporated in the national network. Two approaches for this can be considered:
- Based on distance classes (a quality approach)
- Based on size of the various nodes (a user approach)
The national network is meant to be used for trips ranging from 50–300 km. Accommodating these trips adequately requires an optimal network density, and access point density and this should match the density of nodes. Example: if we apply the same density of nodes as used in The Netherlands, then we need to select approximately 40 nodes (30 in The Netherlands, as the size of the country is smaller). The consequence of this assumption is that we have to select nodes with a number of inhabitants of approximately 30,000.
In the second approach we assume that inclusion of a node in the national network is determined by the number of inhabitants. The number should be higher than 50,000. For theHungarian situation this would result in the inclusion of 21 nodes. Of course, the situation in Hungary differs from the situation in The Netherlands, e.g.,
- The size of the country (area): greater than The Netherlands
- The population density: lower than in The Netherlands
- The distribution of the population; quite unbalanced in Hungary, as the largest node (Budapest) has 1.8 million inhabitants and the second-largest node (Debrecen) only 210,000
It was decided to make a network design starting with 24 nodes (see Figure 2.13): minimum number of inhabitants per node is 40,000. The adopted approach is more or less a combination of the quality approach and user approach. The consequence of this is that the national network will not be used as intensively as in more densely populated countries like The Netherlands.
Step 2: International Connections. These connections have to be dealt with before designing the national network. Budapest is connected with the following large cities abroad (city and direction):
- Bratislava—direction Czech Republic and Slovakia, Poland
- Vienna—direction Austria, Germany
- Maribor—direction Slovenia
- Zagreb—direction Croatia/Slovenia/ Italy
- Subotica—direction Serbia
- Arad/Timisoara—direction Romania