Road networks

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.

Concept

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.


Figure 4 shows several roads which connect to four destinations. The road network is contiguous. Each road has been given a level in an overall road hierarchy for this network. The four levels of the hierarchy are indicated by the letters A,B,C and D.

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

Proposition

  • A road network connects each land use in the area to all the other land uses
Advertisements

About roadnotes

Robert Bartlett is an international consultant with over 30 years of professional experience as a highway and traffic engineer with leading companies and organisations in several countries, including Germany, China (Hong Kong), Qatar and the UK. Specialised in urban studies, transport and the use of GIS, research has included new ideas on subjects such as the study of social justice using GIS, the dimensions of vehicles, and comparative geometrics (highways and transport).
This entry was posted in basics, roads and tagged . Bookmark the permalink.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s