Answer:
When a group of people must decide whether to buy a shared public good or service, the free-rider problem frequently occurs because it is usual that one of the individuals in the group benefits to a greater extent from the one who contributed at the beginning of the acquisition of the good or service. Thus, in economic terms, it obtains a profit greater than that which would correspond to it by virtue of its initial contribution.
This situation is evident in the case of public property of common use (for example, a bridge or the lights of a city), where a person who does not contribute to the acquisition or maintenance of said property (for example, an occasional traveler) can use the asset in the same way as local citizens, who do contribute to that asset. Its frequency occurs because it is impossible, in the case of public goods, for the government to control who uses and who does not use said service in an effective way.
