Prior to the construction of I-80, the US 40 corridor had frequent car accidents. Reasons for this was of the many traffic lights and out-of-nowhere stop signs. Specifically, five intersections were listed with a high accident rate when CalTrans claimed that the construction of the I-80 freeway would reduce the accidents. According to a study done on I-80 in Vallejo from 1955 and 1956, prior to the freeway construction, and 1957 and 1958, after the freeway was constructed, the accident rate dropped 73% and there were 245 fewer accidents on the then-new I-80 freeway.