  The five dimensional Brans-Dicke theory naturally provides two scalar fields
by the Killing reduction mechanism. These two scalar fields could account for
the accelerated expansion of the universe. We test this model and constrain its
parameter by using the type Ia supernova (SN Ia) data. We find that the best
fit value of the 5-dimensional Brans-Dicke coupling contant is $\omega = -1.9$.
This result is also consistent with other observations such as the baryon
acoustic oscillation (BAO).
