Final answer:
A road sign with this message alerts drivers that an additional lane of traffic from another road will merge into the one they're currently on, allowing them to adjust accordingly for safety.
Step-by-step explanation:
A road sign indicating "another road enters the road you are traveling on from the direction shown" serves as an important navigational tool for drivers. It alerts you to the fact that an additional lane of traffic will merge with the road you are on, typically from a side road. Interpreted properly, this sign helps maintain traffic flow and enhances safety by forewarning you about upcoming changes in traffic patterns, thereby allowing you to adjust your speed and position to accommodate the merging traffic.