1. Geographic Accessibility Problems

Three accessibility problems and their solutions are provided below. Solving them requires understanding how to construct Shimbel distance matrices (see Method 2).

• Simple geographic accessibility problem. Finding accessibility for the same number of locations but with different configurations of connections. This example underlines the importance of links.
• An intermediate geographic accessibility problem. A problem involving 7 locations and the impacts of adding one link on accessibility. It compares variations of accessibility in time.
• A complex geographic accessibility problem. A problem involving 8 locations and one-way links (a non transposable accessibility matrix). It tackles with the issue of different emissiveness and attractiveness.

2. Accessibility in a Transport Network

A significant share of urban transport / regional studies aim to find regional accessibility levels and their consequences in space, notably over economic activities. This exercise is a simple application of the accessibility concept to the transportation network of a small city.

The municipal board of a small city (Utopiaville) shired a consultant to measure accessibility of its urban transport network. The city would like to know what would be the impacts of the construction of a ring road over the existing transport network and over the economic activities of its downtown. You are provided with a simplified plan of the transport network and the projected ring road. You must answer these questions:

• Calculate accessibility (geographic and potential) of the existing network (without dotted lines) and identify the most accessible location.
• Calculate accessibility (geographic and potential) of the network if the ring road was built and identify the most accessible location.
• What is the improvement in accessibility and what locations are the most favored by a growth in accessibility?
• Knowing that commercial activities are strongly dependent on accessibility level, what could happen to the commercial activities in the downtown area? In other terms, how would you explain to the municipal board the possible changes in the location of the commercial activities within the city if the ring road is constructed?