Earlier work has found that social capital reduces traffic fatality risk (Nagler 2013a, 2013b). Recognizing that rural areas suffer from high traffic fatality levels despite a perceived high density of communal ties, we explore here whether social capital provides the same protection against traffic risks on rural roads as on urban roads, and what factors might explain differential effects. We estimate simultaneous equation systems of complementary traffic incident types on a 10-year panel of 48 U.S. states. Our results show that social capital has a significantly lower protective effect on rural roads than urban roads. Potentially relevant differentials in crashtype/context exposure (single- vs. multi-vehicle, junction- vs. non-junction) do not mediate this outcome. Rather it appears that the relative prevalence of certain risk behaviors, such as speeding, skew rural environments toward crash situations in which the critical safety factors are orthogonal to social capital influence.