9National HighwayTrafficAdministration,Federal HighwayAdministratiorr Speeding and Highway Safety[Z].The U.S Department of Transportation Policy and Implementation Strategy,1997.
10Boselly,E. S.,Thornes, E.J.,etc.Road Weather Information Systems Volume l:Research Report[R].Strategic Highway Research Program Publication-SHRP-H-350, NationalResearch Council,Washington, D.C.,1993.