A bipartisan duo of senators have reached an agreement on the broad outlines of a tax overhaul for the broken U.S. system of international taxation, one that would create a new low-tax regime for businesses with high income from intellectual property and potentially raise tax revenue for building highways.

Sens. Rob Portman, R-Ohio, and Chuck Schumer, D-N.Y., released the framework for the agreement Wednesday morning. The two have been working for months as the co-chairmen of a bipartisan Senate Finance Committee working group dedicated to finding a solution to the U.S. international tax system, which Schumer described as "upside down and inside out."

"These proposals would right the ship, provide a potential funding source for transportation reauthorization, and allow the United States to compete on a level playing field," Schumer said.

The proposal includes a "patent box," or a special low tax rate for income derived from patents or other intellectual property. The patent box is one of several potential strategies lawmakers have been considering to try to address a major problem facing the country, namely that U.S. companies face incentives to move their operations or headquarters overseas. The patent box is meant to prevent companies with mobile income, such as high-tech and pharmaceutical companies, from shifting that income to low-tax countries or moving out of the U.S. entirely.

The plan does not spell out what that rate might be or what kinds of income might be included.

Portman and Schumer also would overhaul the unusual U.S. practice of taxing all overseas income at the statutory 35 percent rate, which is the highest among advanced countries. Economists blame that worldwide tax system for causing companies to defer bringing $2.3 trillion in earnings back to the U.S. for taxation.

The senators would move to a "territorial system" that would leave foreign earnings untaxed, while imposing new rules to prevent companies from shifting income out of the U.S.

As part of the reform, the $2.3 trillion in earnings would be subjected to a one-time tax at an unspecified rate. Similar proposals were included in both President Obama's budget and in the draft plan for comprehensive tax reform submitted by former House Ways and Means Chairman Dave Camp last year. The revenue could be applied to funding infrastructure in the U.S., a priority for Congress as the highway trust fund faces a long-term funding shortfall.

Rep. Paul Ryan, the Wisconsin Republican who now is chairman of the House Ways and Means Committee, applauded the plan.

In a statement that approved of the main provisions of the senators' plan, Ryan warned that "fixing our international tax system is an urgent task. Without action, more and more American companies will move elsewhere, eroding American jobs and our corporate tax base."