Environmental Engineering Reference
In-Depth Information
Table 4.7
Sustainable mobility—
continued
Policy package
Level of
Summary specification
application
PP14 Slower speeds
Medium
20mph speed limits in all major towns and 50mph speed limits
and ecological
on all rural single-carriageway roads; lower speed limits are
driving
supported by variable signage and enforcement. There is also a
targeted public education campaign concerning ecological driving
skills.
PP15 Freight
Medium
Increase in rail freight capacity between the south coast ports at
Southampton and the Midlands and North, together with advisory
HGV routing.
PP16 Long-distance
Medium
Improved coach/rail links to a range of major destinations,
travel
including London, Oxford and all London airports, and along
substitution
major corridors - Birmingham/Manchester, Oxford-Southampton
(M40/A34 road/rail corridor), Oxford-Bristol (via Swindon).
SCENARIO RESULTS
Absolute
Percentage
(relative to BAU 2030)*
Climate: carbon dioxide (CO2)
-1,365,697
-48.3%
emission reduction (tonnes CO2)
2.0 tonnes CO2 per capita (2030) relative to
BAU of 4.10 (assumed aggregate BAU in
2030 is 2,664,849 tonnes CO2)
Accessibility: improvement in accessibility to town
-3,111
-28.3%
centres by rail (Hansen composite households
**
)
Economy: daily junction delay (aggregate seconds)
-32,092
-20.8%
Local environment: carbon monoxide (CO) (kgCO)
-5,399,618
-41.4%
Safety: Road fatalities (number of fatalities)
22.6
-15.0%
Note
:
**
Hansen composite measures are well used in accessibility planning. They measure accessibility
for a given sub-area (in this case Oxfordshire) to all other sub-areas (all town centres in Oxfordshire).
Pricing (medium), PP8 Parking management (medium), PP9 Park and ride (medium),
PP10 Land-use planning (medium), PP11 Behavioural change (medium), and PP16 Long-
distance travel substitution (medium), for example, all lead to limited CO2 emission
reductions as expected impacts are often masked by other traffic filling up the space
gained in network improvements. The major gains are made when car and freight emissions
are tackled (the vast majority of emissions). The interpretation of these types of result
needs careful consideration. This is not an argument for not investing in the non-car modes,
simply a result of the dominance of car use relative to other travel modes. PPs 1-4, 6-11
and 16 lead to a level of CO2 reduction and they are also useful for non carbon issues,
such as supporting the wider quality of life in urban centres.
The actual modelling assumptions are also critical to the appraisal. For example, the initial
specification of road pricing (PP7) on the major strategic roads in Oxfordshire actually led to
an increase in travel and emissions, as traffic was diverted onto the non-strategic highway
(rural roads) and longer travel distances arose. This again provides a useful lesson in terms
of process - INTRA-SIM and similar appraisal simulations allow a speedy comparison of
