Complex sentence: It is the only section of the original A14 (A1198 road) road that still bears that A14 designation; it was however renumbered as the A604 for a period of time prior to the construction of the current A14.
Split into simpler sentences: It is the only section of the old A14 road that still bears that A14 designation. It was however renumbered as the A604 for a period of time prior to the construction of the current A14.