Low Traffic Neighbourhood Data Unravelling

It has been a bad autumn for supporters of low traffic neighbourhoods (LTNs). Key data they have relied on has been found wanting.

1. Side road traffic figures were wrong

Why does this matter?

Many LTNs were justified on the basis that between 2008 and 2018 traffic on side roads increased dramatically and that LTNs were simply reversing that trend. Satnavs were blamed. For example, Jon Burke, who put in a lot of LTNs when a Hackney councillor, tweeted this: ‘In the past decade, thanks to satnavs, the number of miles driven on residential roads, annually, has increased by 3.9 billion. Since 2006, the number of miles driven on London’s main roads, annually, has fallen by 800 million. That’s displacement for you’. LTNs continued to be justified in this way despite the Department for Transport saying of its old figures “caution is advised when looking at long term trends.” We now know the increase did not happen. As always happens over any period, there would have been an increase on selected roads but there was no overall increase.

2. Low Traffic Neighbourhoods can cause big increases in traffic on other roads

The claim that low Traffic Neighbourhoods cause little or no extra traffic on other roads is still repeated by many LTN supporters. The data collected from the London boroughs, although variable in quality, shows it is not true.  This was confirmed by a report from the Centre for London (1)

Overall the evidence shows big reductions in car traffic inside LTNs, but the picture is more mixed for boundary roads – some seeing increases in traffic and others seeing decreases. How much traffic is displaced onto nearby roads can vary hugely – not only from scheme to scheme but from street to street. In some cases boundary roads have seen big increases in traffic.

The Centre for London added:

No matter how effective low-traffic neighbourhoods are, they can’t remove our reliance on the private car alone. Although they suit local streets, they do little to reduce the traffic on main roads, and in some circumstances can displace traffic into them. They also do not facilitate longer trips that may be challenging to make by public transport or active travel.

3. All the displaced traffic was not counted

It emerged this autumn that the equipment in the road used to count traffic was not able to detect vehicles travelling at less than 10km/h (2). Given the congestion on many of roads taking the displaced traffic, this could be significant. It is thought that this equipment is in widespread use.

4. Little traffic ‘evaporation’ is taking place

The traffic evaporation we were told would take place is, at best, limited. LTN supporters say much less about it now. It was never going to be as widespread as the supporters claimed. The report on which the claims were based was hedged with caveats (3). It said that significant evaporation would only take place in very specific circumstances.

5. LTNs are not encouraging many out of their cars

The theory was that the more pleasant conditions within LTNs would encourage residents to walk and cycle more, particularly for short trips and thus cut overall traffic. What a recent study – carried out by the LTN enthusiast Dr Rachel Aldred – found was that, while there was an increase in walking, and a slightly lower increase in cycling, within LTN, there was only ‘limited’ evidence of a switch from car use and only ‘some evidence’ of decreased car ownership (4).


(1). https://www.centreforlondon.org/wp-content/uploads/2022/06/CFL-StreetShift-LTNs-Final.pdf

(2). https://www.pgweb.uk/forum/palmers-green-town-centre/1432-traffic-evaporation-or-deliberate-undercounting#6621

(3). Traffic Impacts of Highway Capacity Reductions, by Cairns, Hass-Klau and Goodwin, 1998

(4). https://tfl.gov.uk/cdn/static/cms/documents/people-and-places-final-report.docx

One thought on “Low Traffic Neighbourhood Data Unravelling

  1. I live in Haringey and the effect on Bounds Green Road and Green Lanes is total blockage. Local shops going out of business. It is a total disaster. Take the roads back to how they were. Traffic flowed and people got on with their lives.


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