Car traffic and accidents involving cars create an enormous societal cost, particularly in terms of negative consequences for public health. Mitigating these effects is a daily concern for public and private institutions and people around the world. At least a subset of accidents is attributable to the amount of risk drivers allow in their driving and in related behaviour like mobile phone use or substance abuse. Our study looks at the effect of car size on risk taking. While literature highlights several behavioural effects of car size, the direction of causality of these effects is not always clear, and empirical evidence is lacking. Two behavioural and consequential studies support that car size affects risk taking in driving and that this increase in risk taking generalizes to other domains as well. Based on these results and in line with literature showing that social stability and security can affect financial risk taking, we propose the "car cushion hypothesis." This hypothesis suggests that bigger cars make people feel more secure, which affects their behaviour in terms of generalized risk taking. We discuss policy implications aimed at contributing to reducing the societal and public health cost of car traffic.