§ Mr. Marplesasked the Minister of Transport why his Department allowed changes to be made to one of the overhead signs on the elevated section of the M4 near the exit to the South Circular road at midday on Thursday, 11th April, 1968; whether he is aware of the congestion which was thereby caused on the east-bound carriageway; and whether he will make a cost benefit study to optimise the timing of such operations.
Mr. Bob BrownThe delay to traffic was caused by the installation of experimental traffic surveillance equipment on a gantry over the eastbound carriageway. Work of this nature needs to be done in off-peak traffic periods. Sunday work is generally limited to operations which require the complete closure of a carriageway and involves additional costs. In this particular case the acquisition of labour would have been more difficult because of the holiday period. Where it is appropriate to do so the Department arrange for work to be carried out on weekdays between peak traffic periods. Maunday Thursday was chosen for this particular work because traffic is usually well below average just before Easter.
Our engineers understood from the manufacturers, who carried out the work, that the equipment would be installed in half an hour. In fact, the work proved to be more complicated than had been 255W envisaged and took one and a half hours to complete. We regret the delay which was thereby caused to traffic.
We do not propose to make a cost benefit study of these operations. Conditions vary tremendously from site to site. Site features, time of day, likely traffic flow and weather are among those items which are taken into consideration in order to minimise delays to traffic. In our view this is sufficient.