daytime speed limits of or higher along the route. The ACS-Zachry Preliminary Financial Plan showed the expected toll revenue to be collected for Segment 5 and 6 at $14.9 billion over 50 years. The Preliminary Financial Plan for Segment 5 and 6 also showed $12.4 billion in earnings before taxes for the developer. I-69/TTC The second priority corridor for development was the Interstate 69 extension through Texas, which would have roughly followed the route of US 59 from Laredo via Houston to Carthage; there, the national I-69 corridor would have continued northeast into Louisiana and a spur route north to Texarkana would have continued along US 59 to Interstate 30. The original national plan for I-69 also included two spur routes to the Rio Grande Valley following US 281 and US 77; Texas was also studying a connection between the I-69 corridor near Laredo and Corpus Christi known as the "Port to Port Corridor". South Texas officials have pointed out that the Rio Grande Valley is the largest metropolitan area to not have an Interstate Highway system. Texas' portion of I-69 was originally planned to be developed as a traditional Interstate highway (with a mixed-use freeway component only), as it is being developed in other states, but was rolled into the Trans Texas Corridor concept soon after the latter's announcement due to their substantial overlap in purpose and scope. However, on June 11, 2008, TxDOT announced they planned to limit further study of I-69 to existing highway corridors–U.S. 59, U.S. 77, U.S. 281, U.S. 84, and SH 44–outside transition zones in the lower Rio Grande Valley, Laredo, Houston, and Texarkana. TxDOT also announced it was reverting to building I-69 as a standard 4-lane freeway instead of a multi-modal corridor as previously envisioned under the Trans-Texas Corridor concept. The latest plan called for adding a second carriageway and eliminating at-grade intersections along US-59 and US-77 in rural areas, with tolled bypasses around major cities and towns along the I-69 route. According to the Deep East Texas Council of Governments, I-69 is a "future NAFTA Superhighway". It will enter the U.S. from the Mexican state of Tamaulipas. Other potential corridors Texas officials identified several other possible TTC corridors in the long-range plan. Interstate 10 through the southern part of the state, Interstate 20 from east of the Dallas-Fort Worth Metroplex to I-10 near Midland, along an extended Interstate 27 through western Texas,