TomTom, a transportation data company, makes accessible a Traffic Index. The platform provides users with a window into the state of traffic congestion in various cities. The index relies on data from TomTom's various geolocation devices and services. Notably, writing for [The Wall Street Journal](https://www.wsj.com/articles/road-and-transit-use-falls-hinting-at-declining-commercial-activity-11584442801), journalist David Harrison used Traffic Index data to report on transit use during the COVID-19 pandemic lockdown in Boston, New York, Los Angeles, and Seattle, and the pandemic's impact on each city's economy.