Improving Transport Project Appraisals
In the Islamic Countries
57
Table 2.4: VTT in British pounds per hour
Source: ‘Provision of market research for value of travel time savings and reliability’, Department for Transport
(2015)
Methods to estimate reliability impacts are presented in TAG unit A1.3 User and Provider
Impacts26 . All methods measure travel time variability. In case of private travel, the standard
deviation of travel time is used, whereas in case of public transport, the standard deviation of
lateness is used.
Four sources of wider impacts are acknowledged in the guidance:
1. Agglomeration impacts
2. Output change in imperfectly competitive markets
3. Labour supply impacts
4. Move to more or less productive jobs
It is not always straightforward to incorporate the effects on the environment within the CBA.
Therefore, a supplementary guideline on how to account for environmental impacts27 has been
written by the Treasury. Environmental aspects that are usually taken into account are noise,
air quality and greenhouse gas emissions. The guideline states that it is not only important to
take into account the immediate effects on the environment, but also the environmental effects
over the lifetime of the policy or project. The following steps are needed to assess the
environmental effects:
2
2
Value of
travel time
savings
Distance Commute Other
non-
work
Business
All modes All
modes
All
modes
Car Bus Other
PT
Rail
WebTAG
(2014 prices
and values)
All 7.62 6.77 25.47 24.43 15.64 24.72 30.07
All modes All 11.21 5.12 18.23 16.74 - 8.33 27.61
<20 miles 8.31 8.21 - 10.11
20 to 100
miles
16.05 26.85 - 28.99
>= 100
miles
28.62 25.74 -