Two speed limit signs according to regulations.

Quoc Nam, a concerned driver, has reviewed the information regarding two distinct speed limit signs in QCVN 41/2019, the National Technical Regulation on Road Signs. Despite both signs indicating a 50 km/h speed limit, the reader notes a lack of clear distinction, particularly concerning the inclusion of the word "Zone" on one. The fundamental question arises: if both types of signs require an "end of prohibition" sign to terminate the speed restriction, what is the specific purpose and differentiation of the "Zone" designation?

He seeks clarification from experienced drivers to better understand these regulations and ensure proper adherence to traffic laws.