  With the advent of rapid globalization and the inter-border supply chain
network, the reliability and efficiency of transportation systems have become
even more critical. Indeed, trans-continental highways need particular
attention due to their important role in sustaining globalization. In this
context, intelligent transportation systems (ITS) can actively enhance the
safety, mobility, productivity, and comfort of trans-continental highways.
However, ITS efficiency depends greatly on the roads where they are deployed,
on the availability of power and connectivity, and on the integration of future
connected and autonomous vehicles. To this end, high altitude platform station
(HAPS) systems, due to their mobility, sustainability, payload capacity, and
communication/caching/computing capabilities, are seen as a key enabler of
future ITS services for trans-continental highways; this paradigm is referred
to as HAPS-ITS. The latter is envisioned as an active component of ITS systems
to support a plethora of transportation applications, such as traffic
monitoring, accident reporting, and platooning. This paper discusses how HAPS
systems can enable advanced ITS services for trans-continental highways,
presenting the main requirements of HAPS-ITS and a detailed case study of the
Trans-Sahara highway.
