§ Dr. Twinnasked the Secretary of State for Transport whether the results of the surveys of coach speeds on motorways and dual carriageways during 1984 are now available.
§ Mrs. ChalkerYes, the full results will be published in a statistical bulletin next month, but the following table sets out the main figures for the 1984 surveys in comparison with those undertaken in 1983:
Observations of coach speeds 1983–84 Motorways Date August 1983 November 1983 August 1984 November 1984 Number of observations 130 1,163 1,933 1,054 Mean speed (mph) 66.5 62.9 63.2 63.7 Percentage exceeding 70 mph 31 24 24 26 Percentage exceeding 75 mph na 13 12 12 85 percentile 73 73 73 73 Speeds in August and November 1984 are not significantly different. All three later surveys show a lower mean speed and a smaller proportion of coaches exceeding 70 mph than the first survey. However, the first survey results are based on a sample of only 130 observations. The 85 percentile—85 per cent. of coaches travel at a speed lower than 85 percentile—is constant.
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Observations of coach speeds 1983–84 Dual carriageways Date July 1983 November 1983 August 1984 November 1984 Number of observations 431 — 568 346 Mean speed 53.5 — 54.4 51.7 Percentage exceeding 50 mph 64 — 76 66 Percentage exceeding 60 mph 20 — 30 19 85 percentile 61 — 63 60 The speed limit for coaches on dual carriageways was raised from 50 mph to 60 mph in March 1984. Neither the mean speed nor the 85 percentile has changed significantly between July 1983 and November 1984.