Characterizing the ow of Internet trafic is important in a wide range of contexts, from network engineering and application design to understanding the network impact of consumer demand and business relationships. Despite the growing interest, the nearly impossible task of col- lecting large-scale, Internet-wide trafic data has severely constrained the focus of trafic-related studies. In this paper, we introduce a novel approach to character- ize inter-domain trafic by reusing large, publicly available traceroute datasets. Our approach builds on a simple insight the popularity of a route on the Internet can serve as an informative proxy for the volume of trafic it carries. It ap- plies structural analysis to a dual-representation of the AS- level connectivity graph derived from available traceroute datasets. Drawing analogies with city grids and trafic, it adapts data transformations and metrics of route popularity from urban planning to serve as proxies for trafic volume. We call this approach Network Syntax, highlighting the connection to urban planning Space Syntax. We apply Network Syntax in the context of a global ISP and a large Internet eXchange Point and use ground-truth data to demonstrate the strong correlation (r2 values of up to 0.9) between inter-domain trafic volume and the different proxy metrics. Working with these two network entities, we show the potential of Network Syntax for identifying critical links and inferring missing trafic matrix measurements.