Complex sentence: It further found that twenty percent of the state's major city streets were inadequate, that another fifty-five percent would soon be inadequate due to increasing traffic, and that half of the state's secondary roads were unfit for modern industrial traffic.
Split into simpler sentences: It further found that twenty percent of the state's major city streets were inadequate, and another fifty-five percent would be soon due to increasing traffic. Half of the state's secondary roads were unfit for modern industrial traffic.