Data aggregation for VANETs is considered a vital building block for many applications due to its bandwidth saving potential. In this paper, we propose a novel context aware data aggregation technique for VANETs. The data aggregation is done by the cluster head based on the context i.e. vehicle speed and density to reduces the required bandwidth for periodic data dissemination. The proposed technique is validated through extensive simulations and results show that context aware data aggregation can significantly reduce communication cost.