Sequential exit numbering

Sequential numbers

Sequential exit numbering usually begins with exit 1 at the beginning of the road; each subsequent exit is given the next number. Letter suffixes are commonly used when new exits are added. For example, on the New York State Thruway, an exit was added between 21 and 22 where the Berkshire Connector meets the Thruway mainline, and was given the number 21A. Subsequently, a new exit providing access to US 9W was added between 21 and 21A, leading to the sequence 21 – 21B – 21A – 22. In Florida, some new exits got the suffix C, so that if it had or acquired separate exits for the two directions, they would be 15CA and 15CB rather than 15AB. There are also occurrences of this happening on the New Jersey Turnpike; the original interchanges opened in 1951, with newer exits as recently as 2004. On the Baltimore Beltway, there is an exit 12B-C (MD 372), as well as 12A (US 1). There is also an exit 8A (I-895) and an exit 8 (MD 168).