Thanks for your important comments. While nudges are a promising behavior change tool (by the way, I read your blog and PPT on the experiment that your carried out in Kenya), in the medium term, as it is belatedly now been acknowledged in the health sector, there is no substitute for building systems. They are needed in order to sustain the effort over the longer term at the country level. And the need for systems is not theoretical jargon but it rooted on accumulated evidence from developed and developing countries. The challenge is how to support countries in ADAPTING (that is the key word, not adopting mechanically) those experiences to their specific realities and start with demonstration projects in urban areas and high-risk road corridors before rolling out to the rest of the country. And in terms of interventions, there is not a single silver bullet. As shown by recent research, a combined intervention strategy that simultaneously enforces multiple road safety laws produces the most health gain for a given amount of investment (Chisholm et al, 2012).