  Congestion on the roads is a key problem to deal with, which wastes valuable
time.. Due to high mobility rate and relative speed link failure occur very
often. VANET is used to tackle the problem of congestion, and make decisions
well in advance to avoid traffic congestion. In this paper we proposed a
solution to detect and control the traffic congestion by using of both (V2V)
and (V2I), as a result the drivers become aware of the location of congestion
as well as way to avoid getting stuck in congestion. The congestion is detected
by analyzing the data obtained by vehicular communication and road side units
to avoid the traffic. Our proposition system is competent of detecting and
controlling traffic congestion in real-time. V2V and V2I communication network
is used to receive and send the messages. We simulate the result by using
Congestion Detection and Control Algorithm (CDCA), and show that this is one
effective way to control congestion. The Proposed methodology ensures reliable
and timely delivery of messages to know about congestion and avoid it.
  KEYWORD: CDCA ALGORITHM, INTELLIGENT TRANSPORTATION SYSTEM (ITS), VANET, V2I,
V2V.
