  We study $N$ vicious Brownian bridges propagating from an initial
configuration $\{a_1 < a_2 < \ldots< a_N \}$ at time $t=0$ to a final
configuration $\{b_1 < b_2 < \ldots< b_N \}$ at time $t=t_f$, while staying
non-intersecting for all $0\leq t \leq t_f$. We first show that this problem
can be mapped to a non-intersecting Dyson's Brownian bridges with Dyson index
$\beta=2$. For the latter we derive an exact effective Langevin equation that
allows to generate very efficiently the vicious bridge configurations. In
particular, for the flat-to-flat configuration in the large $N$ limit, where
$a_i = b_i = (i-1)/N$, for $i = 1, \cdots, N$, we use this effective Langevin
equation to derive an exact Burgers' equation (in the inviscid limit) for the
Green's function and solve this Burgers' equation for arbitrary time $0 \leq
t\leq t_f$. At certain specific values of intermediate times $t$, such as
$t=t_f/2$, $t=t_f/3$ and $t=t_f/4$ we obtain the average density of the
flat-to-flat bridge explicitly. We also derive explicitly how the two edges of
the average density evolve from time $t=0$ to time $t=t_f$. Finally, we discuss
connections to some well known problems, such as the Chern-Simons model, the
related Stieltjes-Wigert orthogonal polynomials and the Borodin-Muttalib
ensemble of determinantal point processes.
