Complex sentence: To fill this role, yellow-painted vehicles such as the International Travelall and Chevrolet Suburban came into use; as they entered production in the 1960s, vans were converted to school bus use, largely by the use of warning lights and yellow paint.
Split into simpler sentences: To fill this role, yellow-painted vehicles such as the International Travelall and Chevrolet Suburban came into use. As they entered production in the 1960s, passenger vans were converted to school bus use, largely by the use of warning lights and yellow paint.