Transportation always has played a major role in the development of southern California. Los Angeles, CA, was founded when Spanish explorers and padres brought settlers to occupy an area of downtown on Sep 4, 1781. The Los Angeles area experienced more rapid growth of automobile usage than any other area in the world and was challenged to respond. From 1929 to 1949, Los Angeles had the most heavily traveled intersections in the world in terms of automobile passage. The rest of the innovations were the genius of Ralph T. Dorsey, a pioneering Los Angeles traffic engineer from 1923 to 1954. The 1951 ITE meeting in Los Angeles was the first one held west of Chicago, IL, USA. The meeting served as an opportunity for Ralph Dorsey to showcase features of Los Angeles and his accomplishments. The 1969 ITE meeting was an opportunity to identify the progress achieved during the intervening 18 years.