It is widely known that the instantaneous average node speed for the random waypoint (RWP) mobility model may not reach a steady state regime due to velocity gradual decaying which can cause inaccurate results in simulations and communication protocol validations for wireless networks. This paper presents a modification to the RWP model, in which we propose to choose node speeds from a BETA(α, β) distribution, demonstrating analytically and by simulations that depending on the values of α and β parameters the instantaneous average node speed and consequently other important network metrics, like control overhead and number of dropped data packets may reach (or not) a steady state regime. Therefore, by allowing α and β to vary, a multitude of probability distributions for speed choice is obtained and the resulting limiting state behavior for the mobility model can straightforwardly be determined, offering to the research community a generalized BETA random waypoint mobility model. Accordingly, the generic analytical closed form for the instantaneous average node velocity V¯ as Vmin → 0 is obtained as a function of α and β to be given by limVmin→0V¯=Vmaxα−1β+α−1 in which Vmin and Vmax are the minimum and maximum velocities, respectively, that a node can select.