Improving the efficiency and sustainability of transport is a major goal of all ITS programmes around the world. ITS is commonly deployed to deliver improvements in network capacity, traveller mobility, economic productivity and policy-related goals.
There are significant supply-side (network provider) benefits of using ITS for highways management to make best use of road capacity and increase throughput. For example, lane management have been one of the outstanding successes of ITS. This includes High Occupancy Vehicle (HOV) lanes, reversible flow lanes, variable speed limits and enforcement systems. These maximise the use of the infrastructure available, saving or postponing the very large costs of expanding road networks. (See Traffic Control Measures)
Capacity, as defined by the US Transportation Research Board, in its Highway Capacity Manual, is the maximum hourly rate at which vehicles or persons may be expected to traverse a given point – or uniform section of a roadway – under prevailing roadway, traffic, and control conditions.
Throughput is defined as the number of persons, goods, or vehicles traversing a roadway section or network per unit time – and so is very closely related to the concept of capacity. (See http://hcm.trb.org/?qr=1)
Improved vehicle control systems (crash avoidance systems) will increase throughput by reducing the headway required between vehicles. They can also help reduce the number of collisions, which means fewer traffic hold-ups. It has been estimated that a three-fold increase in throughput is possible with platooned vehicle operation. A less sophisticated automated highway system might increase throughput:
Improving mobility by reducing delay, minimising congestion and improving travel reliability is a major goal of many ITS applications. (See Traveller Services) The actual efficiency benefit to the traveller depends on the context. For example:
Travel time savings will depend on levels of congestion and available opportunities for diversion. Among the most common measures is delay – which itself can be quantified in different ways – such as:
Direction and route finding information will generally have value regardless of congestion but there may be potential disbenefits from use of unsuitable roads, especially by heavy goods vehicles. (See In-vehicle Systems) Pedestrians can also benefit in terms of reduction in wasted time waiting to cross streets through smart signal controls. (See Safety of Vulnerable Road Users)
Pre-trip traveller information has benefits for journey planning – in terms of better routeing, knowledge of interchange between modes, or overall journey times. Better informed travellers are able to choose alternative routes and modes, switch to public transport, and save time. (See Travel Information Systems)
While travel cost reduction is of interest to all road users, the benefits associated with ITS are most tangible to the operators of vehicle fleets. ITS productivity benefits have been assessed from the perspectives of fleet managers, transport authorities, and toll agencies. ITS options include automatic vehicle location (AVL) and computer aided dispatch (CAD) using sophisticated logistics software and close 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. In the USA, advanced routeing and decision-making software and organisation for the routeing of time-sensitive deliveries increased deliveries per driver hour by 24%. (See Freight & Delivery Operations)
In freight transport, there are two separate streams of benefits available from ITS:
The first benefit stream concerns the operation of supply chains using data and information linked with communication technologies. Methods include control systems, vehicle tracking and load monitoring – to:
The second benefit stream concerns reducing the costs of transport operators by providing productivity improvements:
The primary measure of productivity is typically cost savings as a result of an ITS implementation.
Canada’s Pacific coast’S BUS OPERATOR, Metro Vancouver’s TransLink, has gained substantial annual benefits in bus idle time savings from a new business intelligence-based solution. This is built on service running data that was already being captured by its ITS-based fleet management system. It achieved avoidance of costs estimated to be CAN$2.62 million. (See Vancouver Savings on Bus Idle Times)
ITS can support policy objectives such as sustainable transport – for example:
These options are becoming central elements of transport and regional economic policy – with the aim of attracting and maintaining investment and ensuring an attractive working and living environment.