Another, much smaller renumbering was carried out in May 1966 after I-84 was built along an alignment similar to that of NY 84. To prevent confusion between the two nearby roads, the section of NY 84 south of Slate Hill was renumbered to NY 284 while the part east of Middletown became an extension of NY 211.
A smaller revision occurred in May 1966 after I-84 was built along a similar path to NY 84. To prevent confusion between the two nearby roads, NY 84's southern part below Slate Hill was renumbered to NY 284, while its eastern segment became an extension of NY 211.