Unlike in some other states, Interstate Highways in New York are not directly referenced by NYSDOT with their number; instead, the letter "I" is suffixed to the number of the route on reference markers and in internal documents. On the surface, there appears to be numerical duplication between several Interstate Highways and state routes—such as I-86 (I-86) and NY 86—but the "I" suffix that is appended to Interstate Highway numbers allows the Interstate Highway and state route to co-exist ("86I" versus "86", respectively).
In New York, unlike in some other states, Interstate Highways are not directly referenced by NYSDOT using their number; instead, a "I" is added to the route number on reference markers and internal documents. There seems to be numerical duplication between several Interstate Highways and state routes—such as I-86 (I-86) and NY 86—but the "I" suffix appended to Interstate Highway numbers enables both the Interstate Highway and state route to coexist ("86I" versus "86", respectively).