Some contagion models of speeding.

Drivers' decision on whether or not to speed are only partially predicted by attitudes towards speeding, beliefs about the consequences of speeding, and police efforts to enforce speed restrictions. We propose that a significant role may be played by drivers' comparisons of their own speed with that of other, nearby drivers. Such comparisons may lead to self-amplifying, nonintuitive consequences at the aggregate level. We present several simple models of these social contagion processes and demonstrate analytical strategies for tracing their implications. We also present some preliminary data suggesting that significant contagion effects exist. Finally, we outline some promising directions for research on contagion effects, and trace their implications for enforcement efforts.