With the automobile industry becoming one of the most advanced industries in the world, roadways are becoming theatres for the showcase of technology innovation. The advent of inventions that were laughingly regarded as scientific fiction some decades back or at least a long way ahead before coming to production, not to talk of popular use has shown the great strides that have been taken by science in the past century. Electric cars, electronic cars, solar-powered vehicles, battery-powered vehicles, hydro-powered vehicles as well as driverless (self-driving, automatic) do not seem so outlandish or out-of-place on our roads anymore. Many are steadily gaining popular acceptance and use in wealthier, more developed climes as cleaner and more climate-efficient alternatives to carbon-emitting, gasoline and diesel-powered vehicles. Equally as beneficial is the fact that the new levels of vehicular systems automation is the corresponding decrease of traffic fatalities and elevated road safety, an effect with long-ranging and far-reaching impact. State-of-the art vehicles require state-of-the-art infrastructure to function optimally. Needless to say, current transport systems around the globe must be quickly adapted and outfitted to support automobile engineering development, lest they be rendered obsolete. 

An important part of Intelligent Transport System in a smart city is the communication networks and technologies that it leverages to collect data, transmit data and disseminate relevant traffic, road and travel information through infrastructure, software and hardware. Technology is therefore being utilized to equip vehicles for communication within themselves and other devices and highway infrastructure. This is achieved through Vehicle-to-Infrastructure Communication and Vehicle-to-Vehicle Communication integration. 

Vehicle-To-Infrastructure (V2I) Communication

V2I Communication is the wireless, bi-directional exchange of data and information between vehicles and road infrastructure components to transmit, store, and deliver accurate data for processing and analysis into real time traffic information disseminated to road users. It is a technology that has seen near-ubiquitous use in Intelligent Transport Systems, as it has been adapted in Intelligent Transport subsystems traffic management, advanced public transit management, transport pricing mechanisms, emergency response management, transport monitoring and supervision systems.

In simpler terms, V2I Communication refers to collaborative and co-opting communication between vehicles and infrastructure to help ensure safe, and secure transportation and vehicular mobility with minimal congestion and shorter travel time. 

How Does V2I Work?

V2I architecture allows equipped vehicles with the necessary apparatus and technology mechanism to allow collection of data on their speed and location and transmission of said data to a central server for fusion, storage, analysis and processing. Held data is then aggregated for ITS applications, such as the determination of travel time from one location to another or predictive analysis. For instance, the server aggregates, from the data collected from vehicles plying a particular highway, all speeds as calculated based on the occupancy, number of vehicles within a specific timeframe, and average length of each car. This enables quick responses to queries for the estimated amount of time it takes for an average car to traverse that road. 

How is this data collected? The collection and retrieval of real time traffic data is basically the function of transportation agencies. This is mainly due to how resource-intensive such collection would be, due to the number of roadway infrastructure apparatus covering all road networks in the city/region. All transport and traffic management systems depend on the accuracy of the data to make predictive analysis and issue real time traffic advisory through various media. 

Common methodologies of data collection involved in V2I include the below listed:

• The use of sensors to detect motion, changes in speed, temperature etc.

• Intelligent beacon sensing techniques

• Placement of pavement microphones to detect sounds such as vehicular honks and beeps; used to determine levels of traffic congestion

• Radio Frequency Identification (RFID) 

• Lane markings 

• Inductive loops; which can be placed in either a single or multiple lanes. They detect vehicles as they cross through the loop’s magnetic field, either recording results in a simple format (by maintaining a tally count of vehicles passing within a time unit) or in a sophisticated (by measuring speed, length and class of vehicles, or by measuring the distance between one vehicle and another). They can work well with slow/stopping vehicles as well as high-speed ones.

• Radar Detection

• DSRC (Dedicated Short Range Communication ; a wireless communication channel specifically designed for automotive uses)

• Bluetooth technology; used to calculate travel time and provide data for origin and destination time

• Wi-Fi

• Mobile-/cellular-phone networks

• Wireless networks 

• GPS positioning technology

• Satellite-navigation systems

• Roadside video camera recognition; including Automatic License Plate Recognition using Optical Character Recognition (OCR)

• Surveillance systems, including Closed Circuit Television (CCTV)  technology

• Joint, multi-agent information fusion (e.g. acoustic+image+sensor; GPS+Satnav+Accelerometer+microphone)

• Connected vehicles and the Internet of Vehicles (IoV)

•  Internet of Things (IoT) 

The vehicle-generated traffic data gathered and collected through the above methodologies by roadway infrastructure, which have been equipped for providing this exchange and mounted at targeted points with high rate of vehicular traffic (e.g. intersections, interchanges, petrol stations etc.), is sent to a central server, which stores the data. Algorithms (deep learning, machine learning, gradients are incorporated to use the data exchanged to perform calculations that recognize high risk situations in advance. Information (advisories) is then disseminated to the vehicle and driver that inform of the driver of existing safety, mobility or environment related conditions. Information derived is often integrated with Vehicle-To-Vehicle Communication for real time advisory. 

ITS applications empowered by V2I communication can be categorized based on the purpose of information provided or on the medium the information is directed to. 

Safety applications seek to reduce greatly traffic accidents through prediction and notification of drivers of the information derived from communications between vehicles and infrastructure on the road network being plied. This could be in form of hazard warnings in form of crash, obstacle or congestion notifications; speed management through Intelligent Speed Adaptation which uses digital speed limit maps and data about the vehicle’s position to alert the driver if the vehicle is or about to exceed such speed limits or communicate with the vehicle automatically slow the vehicle down; intersection safety; merging assistance; priority assignment for emergency response vehicles or even railway crossing notifications. 

Efficiency applications are directed at promoting better utilization of road networks and intersections, in a way to avoid collision or congestion. Often efficiency applications also act as safety measures as well, and they can operate on a local scale at intersections or on intra city roads, or on a wider scale such as expressways or a busy downtown road.  Examples of traffic efficiency information include traffic jam notification; dynamic traffic signaling system such as traffic light control; dynamic traffic control; recognition of potential traffic congestion areas and situations and connected navigation systems. 

Pricing and Payment applications use number plate recognition systems through video cameras and surveillance systems to effect parking control; congestion charges and electronic toll payment. 

Signal Phase and Timing (SPaT) applications occur when V2I Communication is leveraged to align vehicular driving speed with the patterns of a dynamic traffic light system, in a bid to minimize environmental impact by optimizing vehicular fuel economy and regulating speed. 

Infrastructure-specific applications provide an interface with a focus towards the provision of information services to road infrastructure and apparatus. Alerts are relayed by dynamic message systems as in travel time systems; variable speed limit signs and maps; road signage systems and traffic signal controls.   

Vehicle-specific applications interface with vehicle apparatus to channel information using driver-targeted, in-vehicle messaging (e.g. audio route guidance and warning systems in vehicles or navigation information on mobile apps etc.); visible messaging at electronic traffic billboards directed to oncoming vehicles or automated vehicle measures such as restraint systems, braking mechanisms or anti-collision mechanisms.

Limitations of Vehicle-To-Infrastructure Communication

One of the foremost limitations of the V2I Communication adaptation is in its need for public acceptance for effectiveness. 

V2I is a collaborative communication mechanism that requires large scale operations to run and be truly effective. V2I Communication is powered by large tranches of data collected to provide accurate prediction analysis. Apart from needing enough road networks, it must achieve unanimous approval, or at least be hugely popular acceptance for it to be utilized in the transport system as a high number of residents’ individual vehicles and access to vehicle data. An individual having a V2I-equipped vehicle cannot be of much benefit to the Intelligent Transport System, even if the road networks have the necessary communicative apparatus, if other vehicle users do not choose to adopt the system as well, based on whatever reasons they might have. 

Data privacy concerns are a major obstacle to public adoption of V2I communication adoption. Many persons believe that V2I includes some form of tracking and identification technology; which could lead to a compromise of individual vehicle user safety if data from the vehicles is intercepted and hacked to reveal vehicle identity and owner identification information. However, it must be noted that this is only a superstitious myth; as the architecture is designed to foster anonymous data exchange and prevent identification of individual vehicles, as data is sent via encrypted network tunnels indecipherable to the V2I system. Even while detecting signal and speed violations, the identity of violators are still protected. Detection is for safety purposes to alert the violator and oncoming vehicles.

Another limitation of V2I communication is inherent in its architecture and structure. For one, all information received from vehicles through roadway infrastructure is routed to a single, central server. As a result, there is one single point of failure. If the central server is damaged or collapses for any reason, or the link between the server and infrastructure is tampered with or interrupted, the entire process is defeated. Additionally, storage capacity of the central server affects the amount of data that can be stored and data memory. Old data is often totally overwritten to make way for new tranches of gathered data and when lost, cannot be retrieved.

Also, V2I systems are exposed to a high risk of damage, whether such attacks are directed towards in-vehicle components or outer infrastructure. Due to the use of wireless communication, the dynamic topology of network infrastructure and the big size of the network, criminals can manipulate, eavesdrop on or forge the information exchanged in a bid to affect the performance and operation of the network. Magnets, electric shocks and malicious software as in viruses, hacking or jamming can disrupt communication and mess up collaboration. To ensure effectiveness and usability, V2I roadway infrastructure must be built to be durable and not constitute a threat of being hit by the vehicles they are supposed to communicate with. If not embedded in the road (to avoid being broken apart by motorists), then they must be built on the side of the road and shielded, which attracts safety concerns of its own. The presence of firmware as roadway infrastructure for V2I communication purposes means a veritable invitation for tampering, theft and destruction by criminal elements, particularly if such developments are not particularly accepted by the public. If technicians do not have a specific level of knowledge and expertise on V2I systems, they might not be able to recognize signs of tampering. V2I systems thus require a high level of security and extensive knowledge, training and expertise to operate, inspect and maintain them. 

Furthermore, V2I road infrastructure can be painstaking and expensive to purchase, install, operate, maintain and update. Significant capital investments are needed for the adoption of V2I. Institutions and government administrations would rather channel resources into building new roads as opposed to equipping existing ones with smart technology for optimal functioning.  

However massive and insurmountable these challenges might seem, technological and policy innovations can be made to resolve all obstacles (infrastructural, perception-based and architectural) to adoption of V2I Communication as a foremost intelligent transport system component. 

It must be noted as well that there is no smart system that ensures 100% safety on roads at all times. Nevertheless, where there is a system that seeks to ensure traffic safety and keep fatalities to the lowest levels possible by facilitating optimization of what roads are already present, then the rational decision should be to adopt such a system for increased societal development.