Traffic on the Intercounty Connector from the Needwood Road overpass in Rockville in 2011. (Mark Gail/The Washington Post)

TRAFFIC ON the Beltway is getting better, and traffic on the Beltway is getting worse. That information, shared in a AAA study this week, is not much of a revelation. The real news: Where congestion has decreased, commuters may owe their thanks to Maryland’s Intercounty Connector.

The toll road connecting Montgomery and Prince George’s counties was a local transportation hot topic for almost a half-century. In 2011, the artery finally opened. The roadway, as we said many times over the course of the decades-long debate, always had the potential to benefit countless commuters who live and work between the two counties. Now, there’s data to back that up.

Though many of the Beltway’s busiest segments have only gotten busier, AAA’s study shows, on others the flow of cars has thinned — and not where the agency expected. When AAA consulted traffic engineers about its findings, they said the Intercounty Connector might have something to do with the change. A closer look from the Suburban Maryland Transportation Alliance bore that out: Major interstate segments served by the connector have seen traffic decrease by as much as 13 percent since the connector opened, 5 percent on net. Segments unaffected by the artery saw an increase of 2 percent.

Die-hard critics of the connector offer alternate explanations, or excuses: Without knowing the origin or destination of the trips AAA has tracked, it is impossible to say for sure what caused the shift. The millennial generation’s distaste for driving could have played a part, and fewer Americans overall drive to work these days. Some of the changes AAA noticed also may be attributable to job losses in some areas and development in others, such as National Harbor. Still, the numbers are hard to ignore: Parts of the Beltway are getting more crowded. The portions getting less so run parallel to the connector.

None of this should come as a shock. Though the Intercounty Connector did not meet expectations for usage in its early years, in fiscal 2015 trips on the roadway jumped by 18 percent, and for the first time toll revenue topped projections. The connector may have gotten off to a slow start, but it seems things are speeding up.

For decades, the Intercounty Connector’s detractors said the road would cost too much and contribute too little. They kept talking after the project got the go-ahead 10 years ago. Yet even as naysayers continued to claim the Intercounty Connector was overhyped and underperforming, supporters said it would deliver. Looks like they were right.