f Highway Authority Network Classification System - Wiki

Highway Authority Network Classification System

From Wiki

(Difference between revisions)
Jump to: navigation, search
Ahartley (Talk | contribs)
(Created page with 'Comparing crash rates between highway authorities can be misleading due to the variation in road characteristics across the country. For example, it is unlikely that comparing th…')
Newer edit →

Revision as of 09:52, 15 January 2014

Comparing crash rates between highway authorities can be misleading due to the variation in road characteristics across the country. For example, it is unlikely that comparing the crash rate in central London to the crash rate in the Shetland Islands will provide a meaningful assessment of performance. In order to address this issue, Road Safety Analysis have devised a classification system which groups similar authorities together so that meaningful comparisons can be made.

The classification system is based on ‘Network Density’ which is calculated by dividing the total length of roads (km) in a highway authority by the area (km²) of the highway authority. This ‘Network Density’ value gives an indication of how urban an authority is and authorities with similar network density values tend to have similar crash rates. When plotting the crash rate index values against the network density values a correlation was evident with road risk generally increasing as the network density increased. Percentage of urban roads in an authority, as defined by the Department for Transport, are also used in the classification system. Grouping highway authorities using the ‘network density’ and ‘percentage urban roads’ figures led to the creation of 5 super-groups and 11 sub-groups. The parameters for these are shown in the following table:

Sub-Group Sub-Group Description Super-Group Network Density Range Urban Road Range
A1 Very densely networked, super urban London Boroughs A 16+ 97+
B2 Very densely networked super urban authorities not in London B 16+ 90-99
B3 Fairly densely networked, very urban authorities B 10-15.99 90+
C4 Fairly densely networked fairly urban authorities C 10-15.99 70-89
C5 Less densely networked urban authorities C 5-9.99 70-99
C6 Less densely networked mixed rurality authorities C 5-9.99 40-69
D7 Sparsely networked mixed rurality authorities D 2-4.99 40-89
D8 Sparsely networked rural authorities D 2-4.99 20-39
D9 Sparsely networked very rural authorities D 2-4.99 0-19
E10 Very Sparsely networked mixed rurality authorities E 0-1.99 0-39
E11 Very Sparsely networked very rural Scottish Islands E 0-1.99 0-19
Z99 Not classified Z N/A N/A
Personal tools