§ Mr. Hodgsonasked the Secretary of State for Transport (1) what regulations his Department has issued with regard to the method and amount of salt applied to motorways;
(2) when the regulations covering the application of salt to motorways were last revised; and if he will make a statement.
§ Mr. HoramThe Department's revised guidance to agent and local authorities on these matters was last issued in 1976 and remains current.
§ Mr. Hodgsonasked the Secretary of State for Transport what are the chemical constituents by volume of each 100 kilogrammes of salt applied to motorways.
§ Mr. HoramThe Department's agent authorities are advised to use salt conforming to British Standard 3247 Part 1, 245W which has a dry weight chemical composition of:
Soluble chlorides (including Na Cl2, Mg Cl2 CaCl2 etc.) percentage Soluble sulphates (Ca So4) percentage Water insolvents percentage 92 minimum 1.5 maximum 6 maximum Tarces of an anti-caking additive are also included. Current supplies may differ slightly from this specification but are considered to be satisfactory.
§ Mr. Hodgsonasked the Secretary of State for Transport how many tons of salt were applied to motorways in each of the last three years.
§ Mr. HoramApproximately 50,000 tons of salt was spread on motorways in England in 1974–75 and 1975–76, and approximately 80,000 tons in 1976–77.
§ Mr. Hodgsonasked the Secretary of State for Transport how much his Department spent on salting motorways in each of the last three years.
§ Mr. HoramThe cost at outturn prices of motorway winter maintenance in England, which includes salting and snowploughing, in each of the respective years is as follows:
1974–75 million 1975–76 million 1976–77 million £0.9 £1.2 £1.6* *Estimated.
§ Mr. Hodgsonasked the Secretary of State for Transport what is his estimate of the cost of corrosion to road vehicles caused by applications of salt.
§ Mr. HoramIn 1972 the total cost of corrosion to road vehicles in Great Britain was estimated at about £260 million, of which half was probably attributable to salt. No later estimate has been made.