As figure 2 makes strikingly clear, CB radio had been growing steadily from the late 1960s, but this growth exploded in the 1975-77 period.
Instead of changing the law, they would use CB radio to avoid getting caught breaking it.
Thus, CB radio served as a potential cost saver for truckers.
6) Second, the CB radio's benefit depends on the number of users or the size of the network; CB radio is a classic case of a good with "network externality" qualities (Liebowitz and Margolis 1998).
The figure demonstrates the payoff to an individual trucker of having a CB radio as a function of the percentage of other truckers using a CB.
Whether this shock to the value of the communications network is portrayed as a decrease in the benefits of not using a CB radio (because without a CB an individual trucker is more likely to be caught speeding) or an increase in the benefits to joining the network, the effect is the same.
It is unlikely that the spike of CB radio imports in the late 1970s is attributable solely to purchases by truckers; private individuals also owned CB radios.