Transportation is especially important to the region’s economy and quality of life. The D/FW International Airport was one of the first regional transportation collaborations. It spurred economic growth in the area and today serves more than 61 million travelers each year and acts as a major hub for American and Delta Airlines. More recently, civic and business entities have supported additional regional transportation initiatives, including the Trinity Railway Express, or TRE. This commuter rail service was initiated by the cities of Fort Worth and Dallas and is operated by the Fort Worth Transportation Authority and Dallas Area Rapid Transit. The TRE serves an average of 180,000 riders per month.