Introduction to the Special Issue on ‘‘Data management in vehicular
Today, the car is indisputably the most heavily used mode of transportation. Within this context, advances in wireless
networks and mobile devices have motivated the development of a variety of programs, generally involving Intelligent Trans-
portation Systems (ITS). These programs have attracted the interest of researchers both in academia and in industry. Thanks
to the resulting research, Advanced Driver Assistance Systems (ADAS) were born. Some ADAS are already available on the mar-
ket (e.g., navigation systems, warning systems to alert the driver when he/she is about to fall asleep in order to prevent him/
her from crossing the road’s centre line, etc.), and many others are under development. The goal is to provide the driver with
services that can help make the driver experience more comfortable, pleasant, and safe.
The recent development of mobile technologies (e.g., wireless networks, mobile devices, etc.) has led to the emergence of
vehicular networks, which have received a lot of attention these last years, as a medium to provide assistance to drivers.
Several applications are already available on smartphones, such as Waze,
which allow drivers to share
information about trafﬁc conditions or available parking spots. Although such applications suffer from some limitations (e.g.,
required 3G connection, presence of false events due to invalidation problems or malicious behaviors, no assistance provided
to drivers when no events have been recently reported by users, etc.), they constitute ﬁrst valuable contributions in this
Two forms of communication between vehicles are possible: inter-vehicle communications (IVC), also called vehicle-
to-vehicle (V2V) communications, and infrastructure-based communications. IVC relies on short-range networks (about one
hundred meters), like IEEE 802.11 or Ultra Wide Band (UWB) standards, for vehicles to communicate, and provides a band-
width in the range of Mbps. Using such communication networks, the driver of a car can receive information from its
neighbours and disseminate relevant data to other vehicles within its communication range. On the other hand, an infra-
structure-based communication implies the use of a support infrastructure, such as hotspots deployed along a motorway
or a wide-area communication technology (e.g., 3G).
Both types of communication can be used to deliver different types of contents/data to drivers. For example, IVC could be
used to inform drivers that an accident has occurred or that an obstacle has appeared on the road a few hundred meters
ahead. With an infrastructure-based approach, sensors deployed along the network could inform about events such as trafﬁc
jams, parking spaces released or prices of petrol stations nearby, or provide Internet services to vehicles.
Whereas numerous works have focused on the design of network protocols (e.g., dissemination protocols at the network
level, geographic routing protocols, etc.) for vehicular networks, less attention has been paid to data management issues.
Today, although vehicular networks open up very interesting opportunities for the development of original data services,
many challenges lie ahead. For example, data should be released only within the area where they could be interesting, in
order not to communicate irrelevant information or waste network resources. Moreover, not only the spatial criterion is
important here, since a piece of information is usually valid only for a limited period of time. Both the heterogeneity of data
providers (e.g., sensors, neighboring vehicles, Web services, etc.) and intermittent network connections can make data ac-
cess a difﬁcult task; thus, for example, while two moving vehicles exchange data using V2V they could get out of range of
each other. Obviously, trust and privacy issues are also a major concern in such environments, where personal information
(e.g., the location of the user, his/her driving behavior, etc.) is managed.
The purpose of this special issue is to present an overview of the current state of the art and a prospective of the research
issues that need to be solved in order to provide drivers with different types of data services. The special issue opens up with
an invited article contributed by Ouri Wolfson, Prasad Sistla and Bo Xu, who offer their vision on the problem of data
management in vehicular networks and introduce a query language, called TranQuyl, for Data Management in Intelligent
0968-090X/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved.
Transportation Research Part C 23 (2012) 1–2
Contents lists available at SciVerse ScienceDirect
Transportation Research Part C
journal homepage: www.elsevier.com/locate/trc