Complex sentence: Today, many streets throughout California that either follow or run parallel to this historic route still bear the "El Camino Real" name, and much of the original route has been continually upgraded until it is now part of the modern California freeway system.
Split into simpler sentences: Today, many streets throughout California that either follow or run parallel to this historic route still bear the "El Camino Real" name. Also, much of the original route has been continually upgraded until it is now part of the modern California freeway system.