## 4 Conclusions  
In this paper, an experimental platform for research on the automatic control of an articulated bus aiming to allow full experimentation in real conditions for testing technological developments and control algorithms in the field of Intelligent Transportation Systems (ITS) has been introduced. A short review of the state of the art in ITS served as a motivation for the undertaken work, and it was followed by the presentation of the experimental platform, which consisted of a mobile component (a commercial articulated bus fully instrumented) and of a ground test area composed of asphalt roads inside the CSIC premises in Madrid. A robust information acquisition architecture composed of a heterogeneous and complementary set of sensors was implemented and integrated on the platform in order to provide real-time monitoring and control of the multiple variables involved in the autonomous operation of the articulated bus. Details regarding instrumentation and the implementation of bus velocity and steering control, as well as obstacle detection and a human machine interface developed to ease progress in the control system evaluation were provided.  
Experimental testing of longitudinal and lateral control approaches were also presented and illustrated with the results of many tests performed within the experimental area. Experimental results exhibit that the proposed velocity control, which is based on a PID closed-loop controller, is capable of providing automatic regulation of the velocity independently of the road slope and the demanding layout of the bus track. On the other hand, the steering control was shown to keep the lateral error below 0.10 m during the trajectory tracking experiments, which is quite acceptable for a bus of these dimensions. The safety system was confirmed to be effective in detecting dynamic obstacles and sorting them into three predefined warning sections. This strategy allows the articulated bus either to stop or to reduce its velocity depending on the distance between the obstacle and the vehicle. Finally, the HMI proved to be a friendly and intuitive means of communication between the human operator and the controlled articulated bus. The adaptable and open configuration of the HMI enables the real-time control of the system, as well as the real-time visualization of the multiple variables of interest acquired by the sensors.  
In future works, we will implement and evaluate different controllers for this experimental platform in order to compare them in order to reach new conclusions.  
**Acknowledgments: The authors acknowledge partial funding of this research under: IMADE (Instituto Madrileno de Desarrollo) FIE/62/2008 (Comunidad de Madrid), RoboCity2030 (Phase III) S-2013/MIT-2748, Comunidad de Madrid, and ROBSEN (Robotica y Sensores para los Retos Sociales) PI-201650E050, CSIC. [PERSON] acknowledges support from Universidad Tecnologica de Panama. [PERSON] acknowledges the financial support from the Ministry of Economy, Industry and Competitiveness under the Ramon y Cajal Programme.**Author Contributions: The work presented in this article was carried out in cooperation with all authors. [PERSON] designed and wrote the manuscript in collaboration with [PERSON]. [PERSON], [PERSON], [PERSON] and [PERSON] conceived of and designed the experiments. [PERSON] and [PERSON] performed the experiments for autonomous control of the bus and for data acquisition. [PERSON], [PERSON] and [PERSON] processed and analyzed the data and drew the main conclusions. [PERSON] implemented the architecture of the experimental platform. [PERSON] implemented the HMI. All authors contributed to the review of the manuscript.**  
**Conflicts of Interest: The authors declare no conflict of interest.**