ITS and sustainability Chapter | 13 147for mobility by businesses and people (Dirks & Keeling, 2009). Other research-
ers argue that the term sustainability is “a road transport system in which each
user pays at least the full marginal social cost of commuting.” The definition
of Zeitler (1997) for “sustainable mobility” employs “... any form of human
mobility that responds to the various physical (and social) challenges in the least
polluting way ...” and identifies sustainable mobility in the natural way move-
ment, that is, walking and cycling. According to the definition adopted by the
Council of Transport Ministers of the European Union, sustainable mobility can
be defined as a “transport system and transport model that provides the means
and opportunities to meet economic, environmental and social needs efficiently
and fairly,” while at the same time “it minimizes avoidable or unintended nega-
tive effects and their corresponding costs across the different spatial scales.”
According to Richardson (1999, quoted in VTPI, 2004) a sustainable trans-
port system is: “One in which fuel consumption, emissions, safety, congestion,
and social and economic access are of such levels that they can be sustained into
the indefinite future without causing great or irreparable harm to future genera-
tions of people throughout the world”. The World Business Council for Sustain-
able Development defines sustainable mobility as: “the ability to meet society’s
need to move freely, gain access, communicate, trade, and establish relationships
without sacrificing other essential human or ecological values, today or in the
future” (WBCSD, 2004). According to Litman and Burwell (2006), the aim of
sustainable transportation is to ensure that environmental, social, and economic
considerations are involved into decisions affecting transportation activity. Sus-
tainable transport systems must provide a basic requirement to meet society’s
and the economy’s mobility needs as well as social equity. (Williams 2005).
13.2.2 Why sustainable transport is important
Currently, 54% of the world’s population lives in an urban area and the United
Nations predict that this number will rise to 66% by the year 2050. Traffic con-
gestion is a daily occurrence for commuters in urban areas. This contributes
to climate change by producing volumes of greenhouse gas (GHG) emissions
(United Nations Habitat, 2015). GHG emissions are identified as a contribu-
tor to the changing climate (United Nations Habitat, 2015). According to Rice
(2014) and EPA (2014), the climate change will increase overall variability
of temperature, precipitation, and wind patterns. This variability will increase
the probability of heat waves, flooding and/or drought. Thus traffic congestion
problems affect society’s quality of life socially, economically, and environ-
mentally. Intelligent transport systems (ITS) have the potential to alleviate the
unsustainable impacts of traffic congestion and to improve sustainable transpor-
tation systems in the world.
According to Sim, Malone-Lee, & Chin (2001), most important factor for
air pollution in the urban environment is road traffic. In 1990, traffic accident
deaths ranked ninth among the leading causes of death worldwide, with an