Complex sentence: Between 1932 and 1934, the road east of Mecca had been paved;; between 1934 and 1936, US 60 and US 70 had made the shift north towards Indio, and the portion between US 99 and Mecca was paved.
Split into simpler sentences: Between 1932 and 1934, the road east of Mecca had been paved. Between 1934 and 1936, US 60 and US 70 had made the shift north towards Indio, and the portion between US 99 and Mecca was paved.