  Cities around the world are expanding dramatically, with urban population
growth reaching nearly 2.5 billion people in urban areas and road traffic
growth exceeding 1.2 billion cars by 2050. The economic contribution of the
transport sector represents 5% of the GDP in Europe and costs an average of US
$482.05 billion in the United States. These figures indicate the rapid rise of
industrial cities and the urgent need to move from traditional cities to smart
cities. This article provides a survey of different approaches and technologies
such as intelligent transportation systems (ITS) that leverage communication
technologies to help maintain road users safe while driving, as well as support
autonomous mobility through the optimization of control systems. The role of
ITS is strengthened when combined with accurate artificial intelligence models
that are built to optimize urban planning, analyze crowd behavior and predict
traffic conditions. AI-driven ITS is becoming possible thanks to the existence
of a large volume of mobility data generated by billions of users through their
use of new technologies and online social media. The optimization of urban
planning enhances vehicle routing capabilities and solves traffic congestion
problems, as discussed in this paper. From an ecological perspective, we
discuss the measures and incentives provided to foster the use of mobility
systems. We also underline the role of the political will in promoting open
data in the transport sector, considered as an essential ingredient for
developing technological solutions necessary for cities to become healthier and
more sustainable.
