§ 44. Mr. Nabarroasked the Minister of Transport what uses he now proposes for smoke meters for roadside enforcement, similar in general principle to the Ringelmann Chart in the Clean Air Act, 1956.
§ Mr. MarplesThe Ringelmann Chart is not appropriate for measuring exhaust smoke density, since a suitable background is rarely available at the roadside. My Department is, however, undertaking tests with two other types of measuring device. With these we hope to develop standard test procedures for roadside measurement. This should greatly help the enforcement of the law.
§ Mr. NabarroIs not my right hon. Friend aware that this has now been a problem on our roads for more than twenty years and that the first powers were taken as long ago as 1931, yet there has been no improvement at all? Cannot he do something to infuse a little enthusiasm into scientific research circles, notably D.S.I.R., and as the Minister principally responsible, make them realise that this is probably one of the gravest aspects of our road safety problems?
§ Mr. MarplesThe problem all over the world is to find some sort of suitable device to measure this evil. We are pursuing it actively with the Hartridge B.P. light-absorption meter and the Bosch filter-paper meter. These we consider better than the Ringelmann Chart which my hon. Friend mentioned in his Question but which is not suitable for this purpose.
§ Mr. NabarroI did not say that it was. The Question says "similar in general principle." Does not my right hon. Friend know what a Ringelmann Chart is? If he does not, he ought to go and use one.
§ Mr. MarplesI could tell my hon. Friend a lot about the Ringelmann Chart. He must—with his great scientific knowledge—have spent a great amount of time with the Hartridge B.P. light-absorption meter and the Bosch filter-paper meter. 1240 I should be happy to discuss these with him later if my hon. Friend can spare the time.