æt mˈoʊst sˈɛkʃənz, ðə fˈɛdɚɹəl ɹˈaʊt sˈɪksti sˈɪks wʌz bˈɪlt ˌʌndɚ ðə dʒˌeɪkˌeɪˈɑːɹ ˈɑːɹ fˈaɪv ɹˈoʊd stˈændɚd, ɐlˈaʊɪŋ mˈæksɪməm spˈiːd lˈɪmɪt ʌv ˌʌp tə nˈaɪnti kˌeɪˈɛm slˈæʃ ˈeɪtʃ.
At most sections, the Federal Route 66 was built under the JKR R5 road standard, allowing maximum speed limit of up to 90 km/h.