Why did Google Maps intentionally recommend a longer route for some drivers?

Google Research conducted a six-month experiment in ten major U.S. cities to alleviate traffic congestion by rerouting some drivers on longer detours. The study, published in Nature Cities, aimed to distribute traffic more evenly across multiple routes, confirming that this approach can effectively reduce congestion and carbon emissions. By analyzing data from Google Maps, researchers identified congested road segments and implemented minor detours, resulting in a 2% increase in speed and a 0.7% decrease in travel time on busy roads. The experiment highlighted the potential for systemic optimization in traffic management, although concerns about induced demand were noted, as improved traffic flow could encourage more drivers to take to the roads. Overall, the findings suggest that individual decisions can lead to better outcomes for the transportation system.