Final answer:
The proper action when seeing a 'merging traffic' sign is to adjust your speed and position to safely allow vehicles to merge and maintain traffic flow.
Step-by-step explanation:
When approaching a sign that reads "merging traffic," the correct action to take is to adjust your speed and position to avoid a collision. This means being prepared to either slow down or speed up slightly in order to allow merging vehicles to enter the roadway safely. The objective is to maintain a smooth flow of traffic and to prevent accidents, so it's important to be vigilant and considerate of other drivers who are trying to merge.