Insights from a freeway car-to-car real-world experiment

Car-to-car communication is a promising technology for solving several real-life problems on the road. There is a growing research interest in this technology as one of the practical and challenging applications for wireless communication and multi-hop networks. Although there has been a decent amount of research in this topic recently, there is a lack of real-world experimental studies to augment this work. In this paper, we present results from a real-world experiment consisting of 10 cars making loops in a 5-mile segment of a freeway. Each car has a WiFi personal device communicating and forming multi-hop networks with the rest of the devices. By collecting measurements of connectivity and locations from these devices, and analyzing these measurements, we obtain some interesting observations about this environment. For instance, most connections forming in the freeway were between 15 and 30 seconds with a median of 23 seconds. The average distance at connections and disconnections was 133 meters and 500 meters respectively. The distance and relative velocity were observed to have a significant effect on connection forming and duration. Most connections formed were between cars in the opposite directions of the freeway rather than between those going in the same direction. We believe these results are indicative and useful for wireless protocol and application designers.