I nt ernat ional Journal of E merging Trends & Technology in Comput er Science (I JE TTCS) Web Site: www.ijettcs.org Email: editor@ijettcs.org Volume 3, Issue 6, November-December 2014 ISSN 2278-6856 Volume 3, Issue 6, November-December 2014 Page 122 Abstract In Today’s era traffic Congestion is of big issue everywhere in the world. So to combat with this problem many sensors and devices where designed and also many algorithms where implemented which can overcome this problem in some amount. The invention relates to the field of traffic jam discovery, and relates to a traffic jam identifying system and method. Vehicles can directly communicate with each other and with infrastructure; an entirely new paradigm for vehicle safety applications can be created. New challenges are created by high vehicle speeds and highly dynamic operating environments. New requirements, necessitated by new safety- of-life applications, include new expectations for high packet delivery rates and low packet latency. Vehicles generate and analyze large amounts of data, although typically this data is self-contained within a single vehicle. With a VANET, the prospect of awareness for the vehicle or driver drastically increases. Here we define such type of communication and data flow between vehicles and infrastructure. The survey report of previous done work is also mentioned. Here in this paper we discuss various implementations which were already done over traffic congestion detection and also we do the comparison of many of these implementation or the algorithms. Keywords:- vanet, v2v communication, ITC, v2i communication . 1. INTRODUCTION Traffic on road is a major problem today. Lots of hours and tons of fuel are wasted everyday by vehicles jammed in traffic. This is fact that million tons of fuel is wasted today due to increase of traffic intensity [1]. In today’s Technology vehicles themselves have the ability to compile and analyze traffic data and communicate it to the drivers in a layout that will allow them to make smart decisions to avoid congested areas. Communications between vehicles can be attained either through vehicle-to- vehicle (V2V) communications and/or vehicle-to- infrastructure (V2I). Vehicular ad-hoc networks (VANET) [15] are a form of mobile ad-hoc networks (MANET) that provide communications between adjoining vehicles and nearby fixed equipment. Congestion detection algorithms are planned so that we can detect areas which are of high traffic density and low speeds. Each vehicle captures and flows information such as location and speed and route that information received from other vehicles in the network. Congestion detection is one of the many applications of VANETs and it is not designed to be used as means for automated driving but rather as a tool to deliver information to the driver that will help him/her make decisions to avoid heavy traffic [7]. Designing a traffic congestion detection system will have great influence on the budget, the surroundings and society in general allowing us to spend less time stuck in traffic and more time doing some creativity. Fig 1. VANET Concept The Vehicular Ad-hoc Network (VANET) has been studied in many fields [Figure 1] since it has the ability to provide a variety of services, such as detecting nearing collisions and providing warning signals to aware the driver. The services provided by VANET are often based on association among vehicles that are furnished with relatively simple motion sensors and GPS units. Awareness of its precise location is vibrant to every vehicle in VANET so that it can provide accurate data to its aristocrats. Currently, typical localization techniques integrate GPS receiver data and measurements of the vehicle gesture. However, when the vehicle passes through the backgrounds that create a multipath outcome, these techniques fail to produce the high localization accuracy that they attain in open surroundings. Unfortunately, vehicles often travel in environments that cause a multipath outcome, such as areas with high buildings, trees, or tunnels [1]. This research is designed to minimize the effect of multipath outcome with respect to the localization accuracy of automobiles in VANET. The planned procedure first detects whether there is a noise in the vehicle location than it will estimate that is caused by the multipath outcome using neural network procedure. It then takes benefit of the communications among the VANET vehicles in order to obtain more information from the vehicle’s neighbors, such as distances from target vehicle and their location s estimates [7]. The proposed technique assimilates all these pieces of information with A Survey Of Various Algorithms In congestion Detection In Vanet Disha Shrivastava 1 , Arun Agrawal 2 1 Research Scholar Institute of Technology & Management, Gwalior 2 Assistant Professor, Dept. of Computer Science & Engg. Institute of Technology & Management, Gwalior