Vinci's 'La Machine' is not a recent innovation (NCE 8 February).
On a number of interstate highway widening and reconstruction contracts I was responsible for in North Carolina in the early 1990s we used a US made machine which looks identical to that pictured.
It rapidly moved a concrete crash barrier laterally a full lane width, travelling at up to 6.4km/h.
The machine allowed work to be carried out temporarily at periods of lower traffic volumes with a single lane closure, rather than having an extra empty lane coned off for safety as is the normal practice here.
Its use was specied for each contract where repetitive lane closures were necessary on crowded two lane interstates.
The drawback was that the capital cost was quite high for both the machine and the special short concrete barriers needed. Therefore the client, North Carolina Department of Transportation owned the machine and barrier and provided it free of charge for the appointed contractor to use.
That the US and now the French are using such a machine says it all about their attitudes to causing disruption to motorists compared to the British!
Charles M Roberts (F), Chasmroberts@aol. com