Friday Reads – 18 January 2019

1. Ocean Trade route maps.
   Doesn’t include Liverpool or Felixstowe … erm, err …..

   [Greg, in the first paragraph it specifically states that the maps were commissioned to create a series of trade route maps for Wallenius Wilhelmsen Ocean, a global shipping company, as “subway map” visualizations of their network.

   Each maps is also branded “WWO”…

   Do try to pause and have a think before commenting. LBM]

2. Does anyone know what time of year the city traffic survey is done?

3. The City traffic composition report is fascinating for a number of reasons First, that the number of vehicles passing into or through the City has dropped by almost 40% in the last 10 years. This certainly seems to justify the City’s policy of heavily restricting traffic on many roads in the future.

   Second, the growth in the number of cyclists is quite astonishing.

   Third, the inclusion of pedestrian flows shows just how many roads are dominated by pedestrian movement but how few actually give pedestrians decent facilities.

4. @Quinlet – and indeed appears to reinforce the conclusions of much research since the ’80s that the best way to reduce traffic is to reduce road capacity

5. @Bob

   Section 2 of the report says the statistics are collected on one day November. (November 16th in 2017).

6. @Graham H
   Quite so. And it has been done without the economic catastrophe so often predicted as a consequence of road capacity reduction. This isn’t a universal outcome and needs to be planned with some care, but certainly not an unreasonable approach for vibrant cities.

7. @quinlet – the embarrassing thing is that the same applies to the rail network…

8. Does removing capacity (road or rail) reduce travel, or reduce travel by that method? The large increase in other modes suggests the latter.

   I suspect this only works if there is adequate capacity on other viable modes. Not going to work where public transport provision is lacking…

9. @Anonymike – there have been three serious studies of the effects of capacity on demand that I am aware of – two for highways (one by SACTRA on behalf of DTp’s Highways Directorate back in the ’80s, one by the GLA (?) in relation to the closure of Hammersmith Bridge) and one for rail, which Professor Yarrow undertook for me in NSE days. I don’t think that any of these looked at the knock-on impact on other modes, although the SACTRA study was undertaken in areas where the modal split is such that any effects on public transport would be masked, like as not, by other things (your point, in esssence). The NSE study suggested that even on a third order of regression, there wasn’t a great deal of interaction between modes, but then London traffic has always been so congested that the scope for modal transfer is probably (a) limited, and (b) takes the form of some steeply curving function.

10. Much also depends on the type of transport being considered. The SACTRA report was looking at motorway and inter-urban highway connections and primarily longer distance journeys. The GLC (yes, it was them) looked at much more local movement as a consequence of the unforeseen closure of Hammersmith Bridge for structural repairs after it was hit by a boat. I don’t know the NSE study but I suspect it would be city based.

    There are differences. Less capacity on motorways and inter-urban tends to reduce longer distance distribution with more bulk haul movements and more but much shorter distribution movements The former can sometimes be done by other modes such as rail or water, the latter can rarely be done by anything other than road (though very short and small distribution can be done by bike).

    In towns and cities the critical factor seems to be total accessibility by all modes put together As the city gets to be more attractive (better facilities and environment) the property price gradient gets steeper as more journeys are shorter (and therefore amenable to walk or cycle). Much depends on changes at the bargain over time.

11. @Quinlet – I’m not sure that the critical factor is accessibility if, by that, you mean something different to capacity. Again, drawing on highways experience, greater accessibility seems to have relatively little impact on a city’s economy – the classic cases are the demands for ever more motorway exits from places like Cardiff and Newcastle, on the grounds that it would promote growth. Subsequent backchecks have shown that there was no correlation between growth and accessibility.

    A more nuanced view would be that it is changes in the dominant mode in any particular segment that is the determining factor in demand . This would explain the similar results from studies of very different segments.

12. Accessibility is not just capacity, but also ease of use and speed of use compared to what might be achieved. Thus, accessibility by car is not just about capacity but is modified by the slow speeds caused by congestion, the difficulty of finding a parking space and how far you have to walk from the parking space to your destination. Walking may be slower than driving in principle, but most walked journeys are done at a speed close to that which is theoretically possible, unless, of course, the route is blocked by a motorway or major road which is hard to cross.

    The reason I said a totality of accessibility by all modes is that for many journeys there is a choice of mode and that choice is frequently affected by accessibility. So even where there is no congestion, people may be put off from driving if there is nowhere to park. Most journeys are short and many could transfer to walk or cycle without great hardship. If, though, the total accessibility is low (try getting into the Vatican City through the limited access points) then that will also impact on how many people want to go there.

13. @quinlet – of course, generalised speed is one of a number of determining factors, it just isn’t the most important apparently. No doubt this has a lot to do with perception – hope, even – rather than reality

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