Traffic has impacts on the environment. Traffic models are normally used to calculate the traffic intensities on the road network. The calculated traffic intensities form the basis for calculating the environmental impacts. In the impact assessment the traffic intensities are are converted to width of the zone that has negative impacts of the traffic. Examples of relevant environmental impacts are air and noise pollution. The impacted area can be considered as a buffer zone around the road network . To determine what the effects of the impact zone are, it is necessary to calculate the number of houses, inhabitants, the size of the nature area and so forth.
The calculation has two steps:
Step 1) Determining the shape of the buffer zone
Possible approaches to solve the zoning problem:
Figure 1 Illustrative example of a buffer zone
The purpose for step 1) is to develop an algorithm that determines the buffer zone as polygon.
An additional problem is how to eliminate the overlap in the buffer zones in sharp turns, where multiple buffer zones may overlap.
Once the buffer zone has been determined, the next step is to calculate the overlapping area with other polygons such as nature area. For the left hand buffer and the right hand buffer a separate calculation is needed of the overlapping area.
In principle the calculated buffer zone could be exported to Geographic Information System (GIS) to calculate the overlay there. However due to dynamic and interactive character of the traffic model a built-in overlay algorithm would be preferable.
The purpose of step 2) is to develop an overlay algorithm to determine the overlap between the buffer zone and the area of interest. The algorithm should be easy to implement in the traffic model.