At a transportation conference Friday sponsored by Washington Post Live, they also said there is little public pressure for that kind of spending.
"Why haven't we invested? We haven't made a credible case to the American people," transportation consultant Alan Pisarski said.
The American Society of Civil Engineers says replacing roads, dams, bridges, sewer lines and other facilities reaching the ends of their lives will cost $1.7 trillion between now and 2020. A report by a large expert panel headed by former Transportation Secretaries Norman Y. Mineta and Samuel Skinner urged spending of $262 billion a year.
Experts say existing infrastructure is pushed to the limit because of deferred maintenance. At the same time, the country's population is expected to grow about 30 percent, adding 100 million people, by 2050, which will stress the system even further.