In this work we consider the stability of vehicle formations in the case of a varying communication topology. We use a decentralized control law approach and explore the challenges and issues that arise in this framework. The vehicles considered are homogeneous, with discrete-time dynamics, and the communication between them is defined based on a predefined proximity rule. The resulting closed loop system is a switched dynamical system and in this paper we describe sufficient conditions that would lead to the stability of the vehicle formations.