This master thesis overviews the fields of Intelligent Transportation Systems (ITS) and Vehicular Ad hoc Networks (VANETs) and their role in future transport. It describes the key challenges in security with a focus on low-level attacks and vehicle platooning applications. It points out that denial of service attacks could prove particularly disruptive and dangerous in a vehicular network. The project focuses on prevention, detection and mitigation of denial of service attacks in a vehicle platoon. To achieve this, a simulator was created using MATLAB and Simulink that can reproduce the physical workings of a vehicle platoon as well as the wireless communication between the vehicles and the possibility of malicious interference. Defence methods are implemented and tested against jamming attacks. These include methods of interference reduction, data redundancy and warning systems based on on-board vehicle sensors. The results presented are positive and successful in increasing a vehicle platoon s resiliency to attacks. It is the hope of the author that this work along with the simulating environment created, will provide an incentive for further development and examination.