A major truck route leading from the Klamath Falls urban area has a steep grade approaching a traffic light heated by geothermal hot water. This route, the urban portions of U.S. 97 on Esplanade Street, was reconstructed in 1948 in order to widen the bridge across the U.S. Bureau of Reclamation's "A" canal. Since the approach and stop at the intersection with Alameda Avenue cause difficulty with traffic stopped on the eight percent adverse grade, geothermal de-icing was incorporated in the design as an experiment. It was estimated that the pavement would be sufficiently clear of snow and ice to provide free travel at a temperature of -10°F (-23°C), and under conditions of a 3-inch per hour snow fall (S.P. Jones, OSHD, 1967)