θɹuːˈaʊt ðə nˈaɪntiːnhˈʌndɹɪd fˈoːɹɾi z ænd nˈaɪntiːnhˈʌndɹɪd fˈɪfti z ðə ɹˈaʊt wʌz ɛkspˈændᵻd nˈɔːɹθ, bˌʌt ɪn nˈaɪntiːnhˈʌndɹɪd sˈɪksti ˈeɪt ɪt wʌz tɹˈʌŋkeɪɾᵻd tʊ ɪts kˈɜːɹənt lˈɛŋθ.
Throughout the 1940s and 1950s the route was expanded north, but in 1968 it was truncated to its current length.