Urban Its Services and Rnp Parameters

Urban ITS Services on Road Transport:

Urban public transport services have attracted considerable attention in relation to the interaction between general traffic and public transport modes. These transportation services have been characterized with issues regarding the costs of operations and the quality of service across public transportation modes. Given the need for smooth traffic flow, there have been various initiatives geared towards the improvement of urban public transport services. One of the major initiatives that have been adopted in the recent past is the introduction of new systems or Global Navigation Satellite Systems (GNSS) signals. These systems have had tremendous impact on positioning, navigation, and timing for Intelligent Transport Systems (ITS) in urban areas. These systems have been introduced as part of the constant new technology, practices, and research for management of traffic, which is increasingly becoming a complex process and exercise. Intelligent Transport Systems assist in increasing mobility and lessening congestion by supporting urban policy goals in areas like urban logistics and travel information.

There are various kinds of ITS services including collision avoidance, automated highway, road pricing, and intelligent speed assistance systems. Collision avoidance systems have been adopted as part of vehicle and highway automation that is geared towards lessening the risk of accidents, enhancing safety and capacity, lessening fuel consumption, and improving drivers' overall comfort and performance (Vahidi & Eskandarian, 2003, p.143). With the added complexity, the systems have the capability to detect a hazardous situation and notify the driver. Unlike the other systems that require drivers' supervision, collision avoidance systems identify and communicate a hazardous situation. Therefore, they require driver alertness to ensure effective and timely collision avoidance given that the existing control actions are designed for mild automated maneuvers. Some of additional considerations for improving the effectiveness of these systems include accurate modeling of brake or steering components since they may function close to their limits and control design functional limits of the car and actuator saturations.

Automated highway services function on the basis of their relationship between vehicles and the highway infrastructure. These services use vehicle and highway control technologies that move the functions of driving from the driver or operator to the vehicle itself (Cheon, n.d.). The cooperation between the vehicles and highway is geared towards coordinating vehicle movement, evading obstacles, enhancing the flow of traffic, lessening congestion, and enhancing safety. Vehicle intelligence in combined with a set of intelligent technologies like sensor, communication, and obstacle-detection mounted onto the current highway infrastructure. The effectiveness of automated highway services is quite challenging because of the difficulty in automation of driving tasks. This can be achieved by designing vehicle systems to include the complete information used by human drivers with the same degree of intelligence.

A well-developed, wider-range road pricing system is one of the major Intelligent Transport Systems services. This is because of the significance and positive impact of road pricing on the environment and reduction of road congestion. Road pricing in ITS services involve the use electronic charging technologies or systems to manage road congestion. However, these systems need to be technically accurate and strong though they do not have to be complex. Intelligent service assistance is a by-product of significant improvement in speed management and compliance with speed limits. It incorporates a series of technological devices that help drivers in selecting suitable speeds and adhering to speed limits. The use of these devices has been characterized with concerns that they are problematic and unreliable. These issues need to be addressed in order to improve the efficiency of the devices in ITS services.

Required Navigation Performance (RNP) Parameters:

Required Navigation Performance (RNP) is a term that refers to the necessary steering performance for functioning in road transport. The term consist performance requirements and functional requirements for effective operations in road transport. These requirements are crucial for manufacturers of ITS services and drivers or users of the systems. There are four major required navigation performance parameters i.e. accuracy, integrity, continuity, and availability. Accuracy refers to the ability of vehicle systems to function with minimal total system error while integrity is enhancing the operations of these systems to avoid malfunctioning. While continuity is the ability of the systems to avoid loss of function, availability refers to accessibility of the systems to drivers or users of the vehicles.

RNP parameters are vital in today's road transport given the increase of car ownership and travel demand at unsustainable rates (Ochieng, Turhan, Fox & Johnston, 2000). In the modern road infrastructure, they help to address issues associated with road accidents, traffic flow, congestion, and environmental issues. Accuracy in road transport incorporates the functioning of vehicles and associated systems at optimal levels. Integrity provides the basis for user confidence in the precision and reliability of the systems' navigation capability. Continuity and availablity entails satisfying integrity requirement without impromptu interruptions.