This is one of a series of posts on highway engineering. It discusses roads in terms of networks. The text comes from a google knol published in January 2009. The other material from this google knol discusses road hierarchies and road classifications. These texts will be added as separate posts.
A road by itself is simply a line connecting two points. If an area is criss-crossed by many roads they form a road network.
This figure shows a single road linking two destinations
Figure 2 shows roads which connect to four destinations. The lower right destination is connected to the road network. However the road network is not contiguous. This destination does not have a road link to the other three destinations.
Figure 3 shows several roads which connect to four destinations. The lower right destination is connected to the road network. The road network is complete. This destination has a road link to the other three destinations.
Types of road network
here are different types of network, such as:
- road network – a series of interconnected roads. They cover an area and connect a number of destinations.
- 3-dimensional network – a road network in which the individual links have been defined (and perhaps constructed) in terms of a hierarchy of functions (see also “road hierarchy”). Also known as a function-based network.
- 2-dimensional or “flat” network – a road network in which the individual links have not been defined in terms of any hierarchy of functions. Not unusual for cycle or pedestrian networks
- broken network – a network in which the links are not all contiguous; a network to which not all destinations have a connection
- vehicle-based network – a network specific to a particular type of “vehicle”, for example pedestrians or cyclists, or handicapped users.
- purpose-based network – a network specific to a particular type of purpose, such as scenic networks, farm-to-market networks, emergency service networks etc.
- scalar network – a road network which is contiguous regardless of the scale of magnification under which it is being observed
- A road network connects each land use in the area to all the other land uses