Vehicle-to-Infrastructure, or V2I, is a communication system where vehicles send data such as their speed and location to nearby road infrastructure. The infrastructure receives this data, processes it, and sends back information like traffic signal timings. The vehicle then uses this information to adjust its driving behavior, for example, slowing down to catch a green light. This communication happens continuously as the vehicle moves, helping improve road safety and traffic flow. The key steps include the vehicle sending data, infrastructure processing and responding, and the vehicle adjusting accordingly. If the vehicle does not send data, the infrastructure cannot respond properly, and the benefits of V2I are lost.