Let $(W,S)$ be a Coxeter system. The set of reflections of $W$ is $S=\{wsw^{-1}:s \in S, w \in W\}$. The reflection length of $w \in W$ is defined as the minimal number $m$ such that $w = r_1 \cdots r_m$, $r_i \in S$. By a result of Carter: Theorem 1 in the paper, $\ell_R(w) = \dim (Im(w-1))$, $w \in W$.
In type $A$, the reflection length of the longest word $w_0 \in S_n$ is $\lfloor \frac{n}{2} \rfloor$.
What is the reflection length of $w_0$ in other types of Coxeter groups? Thank you very much.