Sprinkle Treatments for Asphalt Concrete, HR-507, 1986

In recent years, the Iowa Department of Transportation has put greater emphasis on improving highway safety. This effort has been relatively successful with a reduction in traffic-related fatalities to levels experienced prior to 1950. The nationwide speed limit of 55 mph was probably the greatest contributor to the decline in traffic fatalities, but there have been many other efforts that have also contributed to this decline. The Iowa DOT has been testing all paved roadways periodically for friction coefficient since 1969. New techniques have been used to obtain a greater depth of surface texture on paved roadways. Transverse tined grooving has been used on portland cement concrete to provide increased texture depth.