Traffic data aggregator Inrix, the company supplying some of the live traffic information used by BMW in its navigation systems, has released a free iPhone app that lets you view traffic information without buying a BMW. The Inrix Traffic app uses a particularly simple interface, a map of your area (located using GPS) that shows traffic flow information and incidents on local roadways. This information is similar to what you would find on an online map or in-car navigation device. Where the Inrix Traffic app differs from these other outlets is its Forecast function, which lets you see what traffic is predicted to look like up to an hour in advance.
Inrix gathers its information from a variety of sources, including local traffic authorities, commercial fleet vehicles that serve as traffic probes, and event schedules, such as sports games. The Inrix Traffic app adds another information source: you. Install and run the app, and it reports its speed and location to Inrix servers, enhancing the quality of the traffic data. Inrix not only uses this information to create a live report, but it also studies the data to understand historical trends, thereby being able to provide its unique traffic forecasting service.
As with most traffic reporting services, coverage is limited to major roads and freeways in specific regions. According to Inrix, it has coverage in 126 cities in the U.S.
We ran the app and compared its information with the traffic feature on Google Maps. Looking at traffic in the San Francisco Bay Area, Google Maps clearly had more road coverage than Inrix Traffic. For example, where Google showed free flowing traffic on Highway 1 from Daly City to Pacifica, Inrix Traffic offered no information. Looking across the country, coverage by Inrix Traffic looks complete for the New York City area, but we found a few spots where Google had the edge, such as Prospect Expressway in Brooklyn, covered by Google, but not Inrix Traffic.
This wasn't a definitive test, as there are many other areas of the country to compare. We also didn't compare the accuracy of the traffic reporting, although in certain areas, Inrix Traffic showed different traffic flow information than Google Maps.