In this paper we analyze the wavefront solutions of parabolic partial differential equations of the type \(\begin{aligned} g(u)u_{\tau }+f(u)u_{x}=(D(u)u_{x})_{x}+\rho (u),\quad u(\tau ,x)\in [0,1] \end{aligned}\) where the reaction term \(\rho \) is of monostable-type. We allow the diffusivity \(D\) and the accumulation term \(g\) to have a finite number of changes of sign. We provide an existence result of travelling wave solutions (t.w.s.) together with an estimate of the threshold wave speed. Finally, we classify the t.w.s. between classical and sharp ones.
