Complex sentence: In 1958, construction of the north--south section of the Palmetto Bypass Expressway started, using SR 826 with a 90-degree eastward curve (the western section of SR 826 was to be abandoned).
Split into simpler sentences: In 1958, construction of the north--south section of the Palmetto Bypass Expressway started. It was designed to connect with SR 826 with a 90-degree eastward curve (the western section of SR 826 was to be abandoned).