$$ \begin{cases} v&=169.1\ut{km/h}=\frac{1691}{36}\ut{m/s}\\ S&=18.4\ut{m} \end{cases} $$ $$ \begin{aligned} t&=\frac{S}{v}\\ &=\frac{18.4}{\frac{1691}{36}}\ut{s}\\ &=\frac{3312}{8455}\ut{s}\\ &\approx0.3917208752217622\ut{s}\\ &\approx0.392\ut{s}\\ &\approx392\ut{ms}\\ \end{aligned} $$