had already been completed; so the runway was allowed to be used as a flight training center. The runway remains today as a part of the Dade-Collier Training and Transition Airport. Also in 1968, construction of an extension of Interstate 75 (I-75) south from Tampa to Miami was started, with an eye toward routing the freeway along an upgraded Tamiami Trail from Naples to a soon-to-be completed SR 836 whereupon it would continue on the east–west highway to its intended terminus at an interchange with I-95. However, planners made the decision in 1973 to shift I-75's proposed route to instead cross the Everglades along Alligator Alley over environmental concerns related to upgrading the Tamiami Trail, which runs along the northern border of Everglades National Park. Additionally, Alligator Alley itself needed upgrading, as the then-narrow toll road was dangerous to both motorists and wildlife (most notably the Florida panther) alike, and SR 836, with its left exits and narrow lanes, was not being built to Interstate Highway standards, with the costs to upgrade it being too expensive. As a result, construction for a rerouted I-75 in southern Florida began in 1974, now with I-75 using Alligator Alley instead of US 41 to cross the peninsula. The configured Interstate would not be completed for another 19 years. Since then, the Tamiami Trail has been designated a National Scenic Byway by the United States Department of Transportation for its unique scenery in the Everglades and the Big Cypress National Preserve. Future Plans In 1928, the Tamiami Trail was considered a feat of engineering, although there appears to have been minimal consideration of the potential damage to the Everglades by the roadway and the Tamiami Canal. Both have acted as a dam to block water flow from Lake Okeechobee to Florida Bay at the southern tip of the peninsula. As a result, the Everglades—the "River of Grass"—has had its water flow greatly diminished over the years, resulting in a devastating effect on the ecology of the region. In the 1990s, a few canals were filled and additional culverts were constructed under US 41 to help regulate water flow. Yet, according to the United States Army Corps of Engineers, this was only a partial solution to the problems of the Everglades and the Tamiami Trail. In 2003, after considering a variety of plans involving the rebuilding of US 41/SR 90, the Corps recommended that a