This gap between demand and capacity is what generates the heavy traffic we face on our highways, the delays we often experience at the airport gate or on the taxiway, the inefficiencies shippers face when their shipments are jammed up in a rail bottleneck, or a port operation struggling with constrained landside transportation access. I am pleased to tell you President Bush recognized the transportation capacity problem in his budget proposal for 2002. We have asked Congress to fully fund the highway and highway safety programs authorized in the Transportation Equity Act for t he 21st Century, or TEA-21. Transit plays an increasingly important role in relieving congestion on our highways. Transit ridership has increased dramatically in the last five years, and we expect even more growth in the future.
Rail is another important option for moving people and goods.
We also need to address capacity in our marine transportation system, which carries about 95 percent of our overseas trade and a significant portion of domestic trade. Existing traffic is already creating severe congestion at our ports, and we expect volume to double by the year 2020. We must find ways to ensure our marine system can continue to provide American businesses with competitive access to world markets. In recent years, we have seen unprecedented growth in the number of commercial air passengers and the amount of air cargo moving in the United States. Here are the numbers.