## 2 Background and Review of Related Works  
### ITS as an Emerging Transportation Solution  
Ensuring sustainable and efficient transport systems include safe travel for every road user is fundamental to economic growth. Roads are a major means of transportation in most cities across the world and provide easy access to jobs, schools, and markets. Therefore, a safe, efficient, and sustainable road transport system is imperative for economic growth. However, there are serious concerns about the negative impacts of transport on human health and the environment including road traffic crashes (RTCs). According to [36], 1.35 million people are thought to die from RTCs every year, and 50 million suffer injuries as a result of RTCs. In addition to the deaths of those who are involved in the accidents, their families and society as a whole are also affected by the aftereffects of traffic accidents, which may include long- and short-term physical injuries for those who survive the collisions [37]. Furthermore, according to WHO [38], the whole cost of RTCs, which includes the economic worth of lost quality of life, costs governments roughly 3% of their gross domestic product. The problem is worse in developing countries because of the lack of suitable and integrated policies and approaches guiding transportation, including failure to give sufficient consideration to road safety features in the design and construction of roads [39].  
More people are becoming aware of the significance of promoting safety in order to achieve successful policy goals. Over the years, various measures aimed at reducing RTCs have been adopted in different countries across the world, most of which have been targeted toward improving behavior, infrastructure, and vehicles. In the past decade, the traditional methods of improving traffic safety by merely deploying traffic lights and signs, using traffic police, etc., have become less efficient and not achieving the intended results as could be seen in increasing crash numbers and associated injury rates. However, recent advances in information and communication technology have contributed to providing other new possibilities, ways, and effective solutions to the transport safety problem. One of these is to use ITS technology, which can be applied in different transport modes and encompasses a very wide range of technologies to deal with different transport issues including transport safety. One of the several advantages when applying ITS technology to transportation projects is to prioritize the safety of all road users, bolster transportation infrastructure, and give road users vital information on safety [40]. This could be done through the integration of advanced communications technologies which focus on both the infrastructure and vehicles including integrated applications between them. It contributes to modifying the way motorists drive by providing information on safety and travel time needed to make informed decisions. It can gather the information required, for instance, to estimate the probability of a collision, identify and confirm accidents, speed up the reaction to traffic incidents, and send out safety messages to road users if an incident happened on their route.  
In developed nations such as Japan, South Korea, Singapore, the United States, and the United Kingdom, ITSs are being used and implemented more frequently to increase the efficacy, efficiency, and safety of road transportation systems [41]. However, this is not the case in developing countries where most governments are yet to adopt and implement policies to readily integrate ITSs into the current transport system. Considering the increasing rate of RTCs and associated injury rates recorded in developing countries annually, it is very important and urgent that ITS-based measures are adopted and must be designed to suit the traffic safety situation of these countries by considering their unique socio-economic and environmental conditions [41].