G1 Definitions

Name

Symbol

Definition

Equation

Age group adjusted composite accessibility score

CAge Group

This combines all the age group adjusted multi-modal scores for the 7 consumed activity types, weighted according to the importance of each activity to the age group.

i

 

1

 

CAgeGroup=Σ Mi .AgeGroupActivityWeighti

 

 

 


i = number of activity types

Age group adjusted multi-modal score

MAge Group

This incorporates all the aggregated accessibility scores for all modes of transportation, for each activity.

The score for each transport mode is weighted according to its importance to each age group.

 

 

 

j

 
k = number of modes considered

Age-
weighted sum of accessible work locations

W

This incorporates all the mode-weighted sum of accessible work locations scores for a site and weights each of these scores according to the fraction of the total working population which that age group comprises.

 

W = Σ Nj . WorkAgeGroupWeight j
               
      1

 

 

 

 

 

j = number of age groups

Aggregated accessibility score

SMode

This is the result of summing all the raw accessibility indices for a particular location, using a harmonic series. Each additional opportunity after accessing the first activity, contributes a smaller fraction of the one before it.

 

Values > 1.00 imply that a particular location has multiple opportunities to access activities from it.

There is an aggregated accessibility score for each transportation mode and activity combination.

 

Note: Places of work are dealt with differently.

 

 

 

n = number of paths

 

 

Comprehen-sive   accessibility score

A

This incorporates all the age adjusted composite accessibility scores for a site and weights each of these scores according to the fraction of the total population which that age group comprises.

 

 

 

j = number of age groups

Deterrence parameter

λmode

The parameter that describes the rate of decay of the deterrence function. The value differs with transportation mode and journey purpose.

 

Mode‑
weighted sum of accessible work locations

NAge Group

This incorporates all sum of accessible work locations scores for all modes of transportation, for the places of work.

 

The score for each mode is weighted according to its importance to each age group when travelling to work.

 

 

 

k = number of modes considered = 4

Raw accessibility index

R

The percentage of people who would make a trip of at least time (t) to access the activity. Expressed as a number from 0.00 to 1.00. This is calculated from the journey time using a deterrence function.

R = emodet

 

t = time minutes

Sum of accessible employment locations

LMode

This is the result of summing all the raw accessibility indices for a particular location for employment locations.

 

There will be a score for each transportation mode.

 

 

n = number of paths

Time

t

The time in minutes to complete a journey from an origin to an activity.