Regarding the Dec. 5 Kyodo article "Panel will probe road infrastructure problems": Metal fatigue is a well-known problem in the aerospace industry and in automobile racing, among other fields. Vibration can cause nuts on bolts to loosen.

Fasteners in critical applications are subject to regular tests to assure their viability. Nuts on screw threads can be assured that they do not loosen with application of simple thread-locking compounds. It would be tragic if simple solutions that are available to the racing and aerospace industries were not applied to the fasteners that secured a portion of the Sasago Tunnel ceiling that collapsed on the Chuo Expressway last Sunday. The fasteners that might have failed are said to have been in place since 1977. It would be criminal if nothing was done during installation to lessen the likelihood that the fasteners would loosen or fail from metal fatigue.

I love and admire Japan, which is one of the most technologically advanced countries in the world. It would be tragic if it is determined that, while the products Japan has exported lived up to and exceeded the best of world standards, Japan's highway infrastructure is Third World when it comes to safety and security.

mahlon craft
norfolk, connecticut

The opinions expressed in this letter to the editor are the writer's own and do not necessarily reflect the policies of The Japan Times.