By the 1930s, US 66 extended from Chicago through Springfield to St. Louis; much of the original pavement was still in use by the early 1940. The dangers of the original pavement were recognized by the nickname "Bloody 66," which reflected the frequently deadly road accidents along the mostly rural route. When World War II erupted, Route 66—already the heaviest trafficked highway in Illinois—saw an increase in military traffic and importance to defense strategy. The aging road's deterioration was hastened by the increase in military truck traffic. The Defense Highway Act of 1941 provided Illinois with about $400,000 in funding, and by 1942, plans were in place to make much needed road repairs that were also intended in part to make the road safer for traffic.