die belebende Bedenkung

Ex post in vacuo

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Improving public transport and encouraging car-pooling, walking and cycling are best for taking cars off the road. There is little robust evaluation evidence on the impact road schemes have on local economic development, wrote Centre for Cities researcher Adeline Bailly on the Centre for Cities blog.

[Is road investment the route to local economic growth?, Centre for Cities, 2 Aug 2017]

The What Works Centre for Local Economic Growth reviewed 2,300 evaluations of the local economic impact of transport projects, and found only 17 robust evaluations looking at the local economic impact of roads – and the findings on impacts are rather mixed.

twitter, @CentreforCities: 'How to reduce congestion? Improve public transport, encourage car-pooling, walking & cycling but not road investment '

But the July 2015 What Works evidence review was mainly concerned with economic outcomes, rather than congestion, and does not really argue the effectiveness of measures for congestion relief.

What Works Growth, Policy Reviews, Transport (extract)

[WWG Evidence Review: Transport – July 2015, extract]

• We found no high quality evaluations that provide evidence on the impact of rail infrastructure on employment, and only a limited number of evaluations showing that road projects have a positive effect.

• We found no high quality evaluations that provide evidence on the impacts of trams, buses, cycling and walking schemes on any economic outcomes.

• Even when studies are able to identify a positive impact on employment, the extent to which this is a result of displacement from other nearby locations is still unresolved. More generally, the spatial scale of any employment effects varies and we do not have enough evidence to be able to generalise about the spatial distribution of effects if they occur. The same is true for other outcomes. The scale at which the studies evaluate impact varies from adjacent neighbourhoods to much larger US counties.

• Surprisingly, very few evaluations consider the impact of transport investment on productivity (we found just three studies, two for roads and one for rail). Although the use of such productivity effects to calculate ‘wider economic benefits’ in transport appraisal is underpinned by a larger evidence base, it is still worrying that so few evaluations can demonstrate that these effects occur in practice.

• We have little evidence that would allow us to draw conclusions on whether large-scale projects (e.g. high speed rail or motorway construction) have larger economic growth impacts than spending similar amounts on a collection of small-scale projects (e.g. light rail or junction improvements).

• More generally, we do not know how differences in the nature of improvements (e.g. journey time saved or number of additional journeys) affect any local economic outcomes.

The review also noted disconnect in the evaluation of schemes, before and after the fact.

Our review of the literature discovered a large number of ex-post [transport investment] evaluations that appear to live in a vacuum, with no attempt made to link the findings from these reports back to scheme appraisals.

Written by beleben

August 15, 2017 at 8:58 am

One Response

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  1. No wonder we have problems – what of the suurge in speculative land purchase & housing development when Airdrie-Bathgate reopened, sadly that boost in land value was not captured to pay for the work.

    Then the JLE which boosted land values to the extent of paying the construction costs almost 4 times over- again never captured to contribute.

    Major boosts to cycle use have been recorded at St Pancras and Waterloo simply because they delivered the transport solution. Crowds travelled to T in the Park by bus because it worked better than any other option.

    Large numbers get to Gatwick by rail – because it works


    August 15, 2017 at 1:28 pm

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