In this paper, the decentralized coordination of point-mass autonomous vehicles at intersections using navigation functions is considered. As main contribution, the inertia of the vehicles is taken into account to enable on-board energy optimization for crossing. In such a way, heavier vehicles that need more energy and time for acceleration or breaking are given an indirect priority at intersections. The proposed decentralized coordination scheme of autonomous vehicles at intersection is compared with an optimal centralized coordination approach and traditional crossing of manned vehicles at intersection with traffic lights. The proposed decentralized coordination scheme shows a significant improvement in energy consumption and in motion smoothness compared to traditional crossing. It is also easier to deploy and more scalable than centralized approaches, with only a limited performance reduction.