October 18, 1967 Motorists may be saying soon that Interstate Five is a groovy freeway, in the literal rather than the hip sense. Crews working in the National City area are using rotary diamond-tipped blades to cut small grooves in the freeway pavement. This is the first time in San Diego County this has been tried. The purpose of the grooves is to reduce skidding, particularly in wet weather. In the Los Angeles area where the grooves have been tested, they said to reduce rainy day accidents by as much as 100 percent. If successful, the method may be used elsewhere in San Diego County.