# Route matrix in the Helsinki metropolitan area

## Scope

What is the road network matrix for the Helsinki metropolitan area?

## Definition

### Data

The current road matrix is based on the following work.

• Helsinki Metropolitan Area Council 129-area classification was used.
• At most one road connection between neighbouring areas.
• Exactly one route between any two areas.

This variable describes a route matrix, which contains the driving instructions from all areas to all other areas. Distances (by road) between the areas are also available.

To make the construction of Route matrix as simple as possible for a new city, the roads are defined in the following way. First, the whole metropolitan are is divided into 15 regions, and these regions are further divided into 129 areas with 7300 inhabitants on average. The 129 areas are standard areas for urban planning, but the regions were formed for this particular purpose. The criteria for forming a region were that they

1. are exclusive and mutually exhaustive
2. are as large as possible without creating very unrealistic routes between areas. Routes are defined in a way that between any two regions, there is only one specific road that is used to cross the region borders (and travel the distance between the regions if they are not neighbours).

It is thus necessary to describe the routes between all areas within each region, and the routes between all regions. However, then it is possible to deduce the detailed routes between two areas that are in different regions using these hierarchical instructions.

The routes are described as lists of areas that are along the road between the origin and destination. The route description needs not be in full detail if the details between two areas are defined in Roads node. A minimum number of existing roads were selected so that the routes in the model would not be very unrealistic. This work was done manually with a map. Note that the absolute numbers of 'Average vehicle flow on the 30 most busy roads' are likely biased upwards because all traffic from smaller streets is packed to the major roads in the model.[1]

Distance data

Lengths of routes and distances between areas.

None defined.

### Unit

km (when applicable)

## References

1. Tuomisto and Tainio: An economic way of reducing health, environmental, and other pressures of urban traffic: a decision analysis on trip aggregation. BMC Public Health 2005; 5: 123 [1].