"Smart" or "sustainably smart" urban road networks? The most important commercial street in Thessaloniki as a case study

In an era where the notion of "smart" has entered almost every sector, including that of transport, it seems more important than ever to preserve the real "smartness" of road networks, addressing the needs of all users, mainly of the vulnerable ones, by means of new technologies in transport sector. The present work reveals the need for designing "sustainably smart" instead of "smart" road networks, referring to the adoption of "smart" technologies in the context of sustainable mobility. Aiming at highlighting problems due to improper or inefficient implementation of Intelligent Transport Systems (ITS) in urban environment, the most crowded and congested street of Thessaloniki (Greece) is studied. It is characterized by severe pedestrian delays and high imposed pedestrian speed at crossings, due to ITS which ensure high priority of motorized traffic over pedestrians at signalized intersections, thus improving vehicle travel times, but highly extending pedestrian waiting times and minimizing green-man phase duration, resulting in significant loss of pedestrian man-hours and in increased safety risk for them. The existing situation is assessed and proposals towards the implementation of the notion of "sustainable intelligence" in a "smart" urban road network, turning it into a "sustainably smart" urban road network, are made.