æz ðɪ ˈɑːptɪməl pˈæθ ɚɹˈaʊnd ɐ ɹˈeɪs kˈoːɹs, ðə ɹˈeɪsɪŋ lˈaɪn kæn ˈɔfən biː ɡlˈɪmpst ɔnðɪ ˈæsfɔlt ɪnðə fˈɔːɹm ʌv tˈaɪɚ skˈɪd mˈɑːɹks.
As the optimal path around a race course, the racing line can often be glimpsed on the asphalt in the form of tire skid marks.