MT 112/159

Emergency traffic signs: rural and urban motorway warning signals; policy

Date range	1964-1969
Location	National Archives (see all files stored here)
Catalogue	See entry
File base	Series MT, subseries MT 112

Context

I came here looking for details on the development of emergency warning signals on motorways and found that the title listed here, and in the National Archives catalogue, is not the one on the front of the file. Or rather, it's only the start of the one written on the front of the file. Its real title is Warning Signs at M5/M50 Junction on Birmingham-Bristol Motorway. And that is precisely what it contains.

Between 1962 and 1970, the M5 south from Birmingham ended at Strensham, the future M50 interchange, and all traffic continued on the M50. Linking the two motorways was a part-built trumpet interchange, ready for the next section of motorway southward towards Gloucester. In that period, after 22 miles of fast motorway driving, all southbound traffic had to negotiate the 270-degree loop of the trumpet. It instantly became an accident blackspot, and stayed that way until the next section of M5 opened.

This file deals with the Ministry of Transport's attempts to make the junction safer. It seems that, as early as 1962, the Road Research Laboratory was conducting trials in Worcestershire of advisory speed signs at sharp bends - the MAX SPEED 30 plates we see now - and suggested they also be trialled on this dangerous bend. The Ministry said no, and didn't change its mind until six years later. On the installation of the signs in 1968, the accident rate dropped immediately. (The looped sliproad, linking two sections of brand new motorway with no speed limit, was signposted for a safe speed of 30mph.)

Police noted that the main problem was not that drivers did not see the warnings for the bend, but rather that they didn't seem to appreciate just how much they had to reduce their speed for it. They noted that lane discipline through the corner was appalling, with many drivers slipping into the hard shoulder.

Contents of note

• Many references to "French horn signs", which turn out to be bespoke warning triangles erected here at the opening of the M5, and designed by Worcestershire CC, that showed the whole of the loop in an attempt to convey the severity of the corner to drivers. There are sketches of these and signage plans that show them.
• RRL report on its trials of advisory signs for bends. As well as advisory speed limits, they also trialled variations of the symbols inside the warning triangle to show how sharp the corner was, and supplementary plates showing a "star rating" for the severity of the bend, with one star for easy corners and three for the most difficult.

People with camera copies

Chris Marshall has a partial copy.