Difference between revisions of "Accessibility"

From Securipedia
Jump to navigation Jump to search
 
(33 intermediate revisions by 4 users not shown)
Line 1: Line 1:
  +
[[Category:Mobility]]
−
= Accessbility =
  
  +
With '''accessibility''' we mean how well a certain area can be reached.
   
  +
== Definition ==
−
Accessibility (or just access) in [[transportation]] planning refers to the ease of reaching goods, services, activities and destinations, which together are called opportunities <ref>From: Litman, T., Evaluating accessibility of transport planning, 2011. URL: http://www.vtpi.org/access.pdf retrieved on April 11, 2012.</ref>. Access to these locations is the goal of [[mobility]]. The ease of reaching these locations is determined by sufficient road capacity and sufficient parking spaces. Are there good options for public transport? What is the average travel time to reach the centre? Accessibility can be defined in terms of potential (opportunities that could be reached) or in terms of activity (opportunities that are reached)<ref>Ibid.</ref>.
+
Accessibility (or just access) in [[transportation]] planning refers to the ease of reaching goods, services, activities and destinations, which together are called opportunities <ref>From: Litman, T., Evaluating accessibility of transport planning, 2011. URL: http://www.vtpi.org/access.pdf retrieved on April 11, 2012.</ref>. For example, is there sufficient road capacity and are there sufficient parking spaces? Are there good options for public transport? What is the average travel time to reach the centre?
  +
Access to these locations is the goal of [[mobility]]. The ease of reaching these locations is determined by sufficient road capacity and sufficient parking spaces. Accessibility can be defined in terms of potential (opportunities that could be reached) or in terms of activity (opportunities that are reached)<ref>Ibid.</ref>.
   
  ⚫
=== Other meanings ===
⚫
A measure that is often used is to measure accessibility in a traffic analysis zone ''i'' is<ref>From: http://en.wikipedia.org/wiki/Accessibility#Transportation, retrieved on April 11, 2012.</ref>:
  
  ⚫
The words accessibility and access can have various meanings and implications<ref>Ibid (1)</ref>.
  +
* In the physical design of urban objects, such as transport modes or buildings, accessibility is described as [[access and egress]] which is the rate or means of entry or exit of an urban object.
  ⚫
* In roadway engineering, access refers to connections to adjacent properties. Limited access roads have minimal connections to adjacent properties, while local roads provide direct access. Access management involves controlling the number of intersections and driveways on a highway.
  +
* In the fields of geography and urban economics, accessibility refers to the relative ease of reaching a particular location or area.
  ⚫
* In pedestrian planning and facility design accessible design (also called universal design ) refers to facilities designed to accommodate people with disabilities. For example, a pathway designed to accommodate people in wheelchairs may be called accessible.
  ⚫
* In social planning, accessibility refers to people’s ability to use services and opportunities.
  +
  +
== Mathematical approach ==
  ⚫
A formula that is often used is to measure accessibility in a traffic zone ''j'' is<ref>From: http://en.wikipedia.org/wiki/Accessibility#Transportation, retrieved on April 11, 2012.</ref>:
   
−
<math> Accessibility_i = \sum_j {Opportunities_j } \times f\left( {C_{ij} } \right) </math>
 +
<math> Accessibility_j = \sum_j {Opportunities_j } \times f\left( {C_{ij} } \right) </math>
 
where:
  
where:
 
* <math>i</math> = index of origin zones
  
* <math>i</math> = index of origin zones
 
* <math>j</math> = index of destination zones
  
* <math>j</math> = index of destination zones
−
* <math>f\left( {C_{ij} } \right)</math> = function of generalized travel cost (so that nearer or less expensive places are weighted more than farther or more expensive places).
 +
* <math>f\left( {C_{ij} } \right)</math> = function of generalized travel cost (so that nearer or less expensive places are
  +
weighted more than farther or more expensive places).
   
  +
In words, the accessibility of a certain destination equals the opportunities in that destination multiplied with the generalized travel costs from each origin to that destination. A destination with many opportunities and short travel times therefore has a higher accessibility than a desination with fewer opportunities and/or longer travel times.
−
A city with a good accessibility has good possibilities to get emergency services to an incident location, or to get people quickly out of the area in case of any danger.
  
   
  +
In transport economics, the generalized cost is the sum of the monetary and non-monetary costs (=monetarized travel time, value of time) of a journey.
⚫
=== Other meanings ===
 
  +
⚫
The words accessibility and access can have various meanings and implications.
 
  +
If the accessibility of a certain location is low, though there are sufficient opportunties, one should consider to improve the accessibility, e.g. by adding public transportation opportunities, lowering the costs of public transport, increasing road capacity, creating more parking spaces etc.
−
* Accessibility generally refers to physical access to goods, services and destinations, which is what people usually mean by transportation.
  
  +
⚫
* In roadway engineering, access refers to connections to adjacent properties. Limited access roads have minimal connections to adjacent properties, while local roads provide direct access. Access management involves controlling the number of intersections and driveways on a highway.
 
−
* In the fields of geography and urban economics, accessibility refers to the relative ease of reaching a particular location or area.
+
Also for security, accessibility is important. A city with a good accessibility has good possibilities to get emergency services to an incident location, or to get people quickly out of the area in case of any danger.
⚫
* In pedestrian planning and facility design accessible design (also called universal design ) refers to facilities designed to accommodate people with disabilities. For example, a pathway designed to accommodate people in wheelchairs may be called accessible.
 
⚫
* In social planning, accessibility refers to people’s ability to use services and opportunities.
 
   
 
== Factors that influence accessibility ==
 
== Factors that influence accessibility ==
   
  +
Transportation demand refers to the amount of mobility and accessibility people would consume under various conditions. Transportation activity refers to the amount of [[mobility]] and accessibility people actually experience. [[modes of transport|Transportation options]] or [[modes of transport]] refer to the quantity and quality of transport modes and services available in a particular situation. Improving the quality and quantity of the modes of transportation means improving accessibility<ref>Ibid (1)</ref>. [[Robustness]] of the transportation network has an influence on the accessibility.
−
Transportation demand means the aggregated amount of mobility resulting from people wanting to access locations. More access
  
   
−
Sometime, a particular factor significantly affects accessibility. For example, inadequate information or poor security around [[Infrastructure#Terminals|public transport terminals]] can constrain public transport use (potential riders don’t know how to use it or have exaggerated fears of discomfort and [[risk]])<ref>Ibid (1).</ref>.
 +
Sometime, a particular factor significantly affects accessibility. For example, inadequate information or poor security around [[Transport Infrastructure|public transport terminals]] can constrain public transport use (potential riders don’t know how to use it or have exaggerated fears of discomfort and [[risk]])<ref>Ibid (1).</ref>.
   
  +
==Related subjects==
−
= MAP =
  
  +
* [[Access and egress]]
−
<websiteFrame>
  
  +
* [[Robustness]]
−
website=http://securipedia.eu/cool/index.php?wiki=securipedia.eu&concept=Accessibility
  
−
height=1023
  
−
width=100%
  
−
border=0
  
−
scroll=auto
  
−
align=middle
  
−
</websiteFrame>
  
   
  +
{{references}}
−
<headertabs/>
  

Latest revision as of 10:31, 20 August 2013

With accessibility we mean how well a certain area can be reached.

Definition

Accessibility (or just access) in transportation planning refers to the ease of reaching goods, services, activities and destinations, which together are called opportunities [1]. For example, is there sufficient road capacity and are there sufficient parking spaces? Are there good options for public transport? What is the average travel time to reach the centre? Access to these locations is the goal of mobility. The ease of reaching these locations is determined by sufficient road capacity and sufficient parking spaces. Accessibility can be defined in terms of potential (opportunities that could be reached) or in terms of activity (opportunities that are reached)[2].

Other meanings

The words accessibility and access can have various meanings and implications[3].

  • In the physical design of urban objects, such as transport modes or buildings, accessibility is described as access and egress which is the rate or means of entry or exit of an urban object.
  • In roadway engineering, access refers to connections to adjacent properties. Limited access roads have minimal connections to adjacent properties, while local roads provide direct access. Access management involves controlling the number of intersections and driveways on a highway.
  • In the fields of geography and urban economics, accessibility refers to the relative ease of reaching a particular location or area.
  • In pedestrian planning and facility design accessible design (also called universal design ) refers to facilities designed to accommodate people with disabilities. For example, a pathway designed to accommodate people in wheelchairs may be called accessible.
  • In social planning, accessibility refers to people’s ability to use services and opportunities.

Mathematical approach

A formula that is often used is to measure accessibility in a traffic zone j is[4]:

where:

  • = index of origin zones
  • = index of destination zones
  • = function of generalized travel cost (so that nearer or less expensive places are

weighted more than farther or more expensive places).

In words, the accessibility of a certain destination equals the opportunities in that destination multiplied with the generalized travel costs from each origin to that destination. A destination with many opportunities and short travel times therefore has a higher accessibility than a desination with fewer opportunities and/or longer travel times.

In transport economics, the generalized cost is the sum of the monetary and non-monetary costs (=monetarized travel time, value of time) of a journey.

If the accessibility of a certain location is low, though there are sufficient opportunties, one should consider to improve the accessibility, e.g. by adding public transportation opportunities, lowering the costs of public transport, increasing road capacity, creating more parking spaces etc.

Also for security, accessibility is important. A city with a good accessibility has good possibilities to get emergency services to an incident location, or to get people quickly out of the area in case of any danger.

Factors that influence accessibility

Transportation demand refers to the amount of mobility and accessibility people would consume under various conditions. Transportation activity refers to the amount of mobility and accessibility people actually experience. Transportation options or modes of transport refer to the quantity and quality of transport modes and services available in a particular situation. Improving the quality and quantity of the modes of transportation means improving accessibility[5]. Robustness of the transportation network has an influence on the accessibility.

Sometime, a particular factor significantly affects accessibility. For example, inadequate information or poor security around public transport terminals can constrain public transport use (potential riders don’t know how to use it or have exaggerated fears of discomfort and risk)[6].

Related subjects

Footnotes and references

  1. ↑ From: Litman, T., Evaluating accessibility of transport planning, 2011. URL: http://www.vtpi.org/access.pdf retrieved on April 11, 2012.
  2. ↑ Ibid.
  3. ↑ Ibid (1)
  4. ↑ From: http://en.wikipedia.org/wiki/Accessibility#Transportation, retrieved on April 11, 2012.
  5. ↑ Ibid (1)
  6. ↑ Ibid (1).
Retrieved from "https://securipedia.eu/index.php?title=Accessibility&oldid=13062"