Road Network Operations
& Intelligent Transport Systems
A guide for practitioners!
Road Network Operations
& Intelligent Transport Systems
A guide for practitioners!
New technologies, termed Intelligent Transportation Systems (ITS), provide a means to acquire a better knowledge of the transport network and to implement every available means to optimise network operations, traffic management and services available to customers. These technologies thus become an integrated element of the concept of network operations facilitating the improved efficiency of the transportation system.
ITS can maintain or expand the level of service to road users by increasing throughput (measured in terms of the number of people, or number of vehicles, or amount of goods moved per unit time). ITS can also support management of infrastructure at times of extreme events (for example flooding, extreme storms), by providing high-performance real-time information to operators and users. (See ITS Applications and Services)
From the perspective of road owners and operators many ITS products and services improve efficiency by optimising the use of existing facilities and rights-of-way. With these improvements, requirements for mobility and commerce can be met and the need to construct new or expanded facilities can be reduced. ITS provides a tool kit for transport network managers to use for increasing efficiency; improving safety; encouraging alternative modes and assisting with the management of roadway maintenance and construction. (See Benefits of ITS)
The formal evaluation of benefits from ITS applied to network operations is a specialist area. Many results, articles and discussion papers can be obtained through the International Benefits, Evaluation and Costs Group (See IBEC), from the European Evaluation Expert group and for North America at the USDOT ITS Benefits web site. The Deming wheel principle of continual improvement applies (PDCA cycle). (See Evaluation)
The major functions of ITS applications in Road Network Operations are:
Timely warning of unsafe road conditions and congestion reduces the occurrence of accidents and collisions. Incidents such as crashes and vehicle breakdowns as well as impassable/ unsafe road conditions are estimated to cause up to 60% of annual roadway congestion in some congested networks. The traffic congestion that results from these incidents can lead to additional crashes and cause delayed response to emergency situations. According to one study, for every minute an incident remains on the roadway, it causes an additional five minutes of delay after the incident is cleared. Other solutions include better road works planning, lane restrictions, bad weather and road conditions alerts, and automatic braking systems. (See Traffic Management Strategies, Driver Support, Travel Information Systems and Traveller Services)
ITS and related technologies have been widely accepted by both the public authorities and the private sector as a way to achieving the goal of sustainable mobility – while at the same time improving quality of life. For example:
There are significant supply-side benefits of ITS in highways management. Improvements in the infrastructure affect directly each vehicle/driver using the roads. Lane management has been one of the outstanding successes of ITS. This includes HOV lanes, reversible flow lanes, variable speed limits and enforcement systems.These systems maximise the use of the infrastructure available, saving or postponing the very large costs of expanding the networks. (See Advanced Systems and Traffic Management)
While cost reduction is of interest to all road users, the associated benefits of ITS are most tangible to the operators of vehicle fleets and highway infrastructure. Productivity benefits have been assessed from the perspectives of fleet managers, transit authorities, and toll agencies. ITS options for fleet operations include Automatic Vehicle Location (AVL) and Computer Aided Dispatch (CAD) using sophisticated logistics software and communications between the dispatcher and the driver. Each individual intervention appears marginal, but the overall effect in journey time reliability and time savings can make the difference between hitting a Just-in-Time delivery slot and missing it. (See Passenger Transport Operations and Freight & Delivery Operations)
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