—Vehicular ad hoc networks (VANETs) are envisioned to provide promising applications and services. One critical deployment issue in VANETs is to motivate vehicles and their drivers to cooperate and contribute to packet forwarding in vehicle-to-vehicle or vehicle-to-roadside communication. In this paper, we examine this problem, analyze the drawbacks of two straightforward schemes, and present a secure incentive scheme to stimulate cooperation and contribution in VANETs. We first define the measurement of contribution according to the unique characteristics of VANET communication. Our scheme uses the weighted rewarding component to ensure fairness.