"Now it is also true that LTNs do result in some traffic evaporation - the amount varies depending on design of LTN, but in all cases it is a non-negligible amount."Or in other words, LTNs have reduced overall traffic.The impact (by design) is to move traffic off minor residential roads and onto main roads - which are designed to take the traffic - and encourage a modal shift in journeys.The criticism is that this is unfair on those who live on main roads (anti-poor, racist etc.) as it is assumed only poor people live on main roads as the housing is cheaper. They suffer in two ways - first all the traffic, noise and pollution and secondly, if you assume no traffic evaporation, more congestion, which makes the noise and pollution worse. While discussing this with someone who was up in arms about the impact on the Great Chiswick Road, I (satirically!) suggested we follow Heathrow's example and give respite to the people who live on the A4, by closing it for a week a month and sending the traffic down alternative routes.He shot back that it was a bit different as the A4 was a 6-lane motorway - GCR was an A-Road, so hardly the same thing.I think even the people who make the arguments that it is unfair to push traffic onto main roads draw the line at doing anything about those who live on the biggest ones.There's been substantial growth in traffic over the last few years - most of it happening on minor roads - and apart from the hassle, noise, dirt and danger, air pollution increased to alarming levels.The point about LTNs and active travel infrastructure isn't actually to give unfair respite to white, rich people. It is a step in first containing traffic before then reducing it. Tom and others have noted that average times for buses and journeys haven't increased by much or at all. Anecdotal evidence (mine included) is that at certain times, you can get snarled up in traffic that turns a 10 minute local journey into a frustrating 60 minute one. One effective way to decrease local traffic - the one that got me out of a car and onto a bike for some trips - is to increase journey times by car. If it is 90 minutes to drive up and down CHR, you going to walk it if you are able and probably delay / reschedule the trip if you can't.I'm not suggesting LTNs are designed to infuriate motorists out of their cars, although when TFL state that it expects traffic to "settle", I think there's some of that going on. However, B & C roads have acted as an escape valve for growing traffic over the last decade, and in many areas they're being switched off. Reducing road capacity is part of a strategy to reduce traffic. And the new escape valves? Residential roads that are nicer and safer to walk / cycle in and new non-vehicle infrastructure.
Ed Saper ● 1970d