What is the "post Roads" restriction?

The Boston Tea Party was a demonstration against a government transportation monopoly that triggered a war. To prevent the Federal government from repeating the defects of the King, 8 states voted against 3 states on Sept. 14, 1787, forbidding Federal taxing for roads and canals beyond what was essential to deliver letters if no other means were available.

When did the Federal government start taxing to build roads?

With the 16th and 17th Amendments in 1913, the structure of the Constitution that once enforced Divided Sovereignty (Federal over issues of war, with the people and states over all else) was removed. The Federal government is forbidden to tax to provide welfare (Preamble, restated in Amendments 9 and 10). Within 3 years, however, with The Federal-Aid Highway Act of 1916 enacted, the Federal government began building a monopoly that would replace 46% of the 400+ ton-mpg railroads with 25 mpg highways. So began Federally mandated Climate Change.

What about China and India?

After winning World War II, governments around the world adopted the example of the US Federal government, creating oil/coal burning infrastructure monopolies. Those monopolies are the root cause of global Climate Change.