Two Percent of Routes Can Loosen a Whole City

Google Research modified routing recommendations around recurring bottlenecks while keeping alternative routes similar in travel time and road type. Fewer than two percent of observed trips changed, yet the study reports median speed gains of about two percent on targeted segments and smaller positive effects across all affected roads, with estimated fuel-use reductions. The experiment alternated treatment and control days over six months in ten cities. It does not establish that every city or navigation system will respond alike, but it shows how optimizing a small set of individual trips can improve a shared network rather than merely moving one driver faster.