Given the recent advances in information technology, speed has become an important requirement in data transmission. In this regard and given that an LED (light emitting diode) can turn on and off for several thousands, even millions, of times per second, then LiFi (light fidelity) technology has strong advantages over WiFi (wireless fidelity) in terms of speed in data transmission. In this research project, a consortium of industrial and academic partners have decided to evaluate the maturity of LiFi technology by designing a demonstrator that showcases an efficient and speedy intra-vehicle data transmission system. The demonstrator implements a two-way LiFi communication between the reading light of a vehicle and a portable device, such as a tablet or smartphone. This nomadic device must display, via an interface, receiving transmitted data in real time. The data is of type RNT (Digital Terrestrial Radio) and TNT (Digital Terrestrial Television) provided by an in-house antenna. LiFi depends on optical technology hence, the devices' optical characteristics have significant influences on the system. This paper presents various conducted experiments and techniques to improve the system's throughput, communication range, and reception area. For instance, by replacing the reading light with one of better optical characteristics, the communication range and reception area improve. By using symmetrical power supply, the throughput improves. Also, by using optical filters that eliminate noise, throughput also improves. We have indeed demonstrated that LiFi data transmission in the vehicle is feasible; low-definition videos were successfully transmitted. The paper also presents various techniques to still improve its system performance.