## 1 Introduction  
Recently, Vehicular ad hoc networks (VANets) are emerged as challenging and advanced networks, having lots of sensors and onboard devices for V-2-V (vehicle to vehicle), V-2-I (vehicle to infrastructure) and V-2-P (vehicle to pedestrian) communication, in addition with high speed and random topologies. As VANET is one of the important parts in implementing intelligent transportation systems (ITS) in which trust management [1; 2; 3] can play a vital role to improve traffic efficiency, human safety and reduce energy consumption. At the same time, with the increasing popularity of sensing technologies and hand held devices, a new sensing paradigm, mobile crowd sensing, attracts attention from both academia and industry [4]. This new sensing paradigm leverages the power of crowds for large scale sensing tasks and fuels the evolution of the Internet of Things (IoT). Today, vehicles on a highway can be a great opportunity for resource sharing, infotainment and commercial advertisement in an efficient manner. A possible future scenario of vehicular networks can be seen in Figure 1, these distributed networks will rely on each other for resource sharing, which demand secure communication to be disseminate. As VANET, due to its openness not only face security issues that describedpreviously [5], but also come up with new challenges like high speed, large scale network that makes VANET a truly challenging network [6]. As a result, number of research efforts have been made to ensure the credibility of sensed data. [7]. Many authors tried to provide solutions using cryptographic and certificate exchange methods for securing ad hoc networks [8; 9]. Similarly, most of the anonymous routing protocols like ANODR [10], AASR [11], also based on cryptographic and public key infrastructure mechanism for establishing secure connection, thus increases routing overhead. One possible solution is to establish the trust management system for evaluating the trustworthiness of volunteer contributions in participatory sensing applications [5]. Further, trust management succeeded to handle many security issues with lightweight solutions. Trust management enforcement in ad hoc networks enables system to derive collaboration, avoid untrusted and malicious nodes and improve network performance [12]. [PERSON] et al. in [13] give a detail information about trust management in VANET and also highlight the challenges for its deployment. [PERSON] and parasat in [14] feasibly describe various trust computing approaches that are geared towards VANET. However, many trust management solutions rarely considered uncertainty as important notion in these ad hoc networks and that needs careful treatment. To manage uncertainty between distributed nodes author in [15] proposed subjective logic for determining probabilistic uncertain values over [0, 1]. This subjective logic succeeded to reduce computation overhead with simple network topology, while comes up as information loss by network canonization in complex and random network topology [16]. Precisely, to tackle with above situation [PERSON] et al. in [17; 18] proposed Three Valued Subjective Logic to manage the uncertainty more significantly. Despite the existing methods, vehicular networks still need a comprehensive research and lightweight solutions. In this paper, we propose a secure extended routing protocol, which is called 3 VSR, to credit the user by establishing a trust and reputation system. In this system, a group of vehicles is able to  
Figure 1: A possible future scenario in vehicular networks. authenticate each other and to distinguish the well-behaved and badly behaved vehicles according to their trust scores. To mitigate the negative impacts of those malicious user vehicle, we design an vehicle authentication algorithm for our proposed scheme to exclude their impact.