The United States has edged closer to signing up to an international deal which would save millions of dollars for auto manufacturers by removing one of the biggest barriers they face to trade worldwide.

Significant progress has been made in attempts to get the United States to take part in a deal paving the way for globally recognized performance tests on autos and auto parts, diplomats from the European Union and the United States report.''We made good progress in the latest talks but there are still some problems to solve,'' said one European source who asked not to be identified.

A further round of meetings will be held in March with the possibility of a midyear agreement, say some diplomats.

At the moment, auto manufacturers have to produce anything up to 40 different versions of the same basic model to suit local performance specifications. Uniform performance tests would offer them the chance for the first time of producing a truly global auto.

Tailoring designs to meet national specifications not only costs a large amount of money, 10 percent to 15 percent of production costs, says European car lobby ACEA, but also provide an easy excuse for foreign countries to block and delay imports. Manufacturers do not even bother to try and sell in some markets because of their tests, said an ACEA spokesman.

The United States and the EU have both complained that Korea used its highly particular performance tests to brake western car sales.

The international deal taking shape has Japan already committed to sign up to an existing United Nations Economic Commission for Europe agreement which has already established the same performance tests for autos in west and eastern Europe, including the former Soviet Union.

U.S. membership could be possible through a parallel agreement taking into account its system for individual manufacturers, not governments, to certify that autos are fit for domestic and export markets.

With the world's three leading trading blocs signed up, an international system for performance tests could be introduced embracing the rest of the world. Under the new mechanism, signatory countries would vote for a global test from the national candidates put forward for consideration in a sort of beauty contest. Autos and parts passing the worldwide tests would have to pass national tests before they could be marketed.

One issue still worrying the EU is just how far the formula for U.S. membership will commit Washington to a meaningful involvement in the process.