Road Network Operations
& Intelligent Transport Systems
A guide for practitioners!

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Environmental and Social Benefits

Planners are increasingly concerned with climate change and ‘greenhouse’ gas emissions. Transport is a major source of pollution which has health and quality of life implications. ITS can help ameliorate – for example, by smoothing traffic flows, reducing energy consumption and vehicle emissions. Performance measures for assessing the impact of ITS include reductions in emission levels (Carbon Monoxide, Nitrogen Oxides and Hydrocarbons) and better fuel economy.

In most situations, local analysis and simulation are needed to estimate the environmental benefits of a specific ITS project (See Project Appraisal).

It is difficult to measure environmental impacts on an entire region because of the large number of other variables including local terrain, road geometry, weather and contributions from non-mobile sources. For example:

  • noise and vibration can be an issue, for example, when traffic control systems relocate traffic queues as part of a queue management strategy
  • visual intrusion can be a problem where overhead gantry signs are required.
  • direct measurement of environmental impact can focus on a localised measure such as air quality surrounding a particularly congested intersection or other sensitive areas

The potential application of ITS to address environmental and societal challenges is an increasingly important emerging area. The main challenges being addressed are:

Air Pollution

People want healthy, attractive and comfortable living environments. Tough air quality standards are being imposed in many countries. One way of enforcing these standards is by creating low emissions zones (LEZs) – such as those introduced in Sweden in 1996. Vehicles which do not comply with the emission standards are required to pay a penalty charge. Automated enforcement is typically by camera supported by ITS-enabled back-office enforcement operations.

The enforcement of vehicle emissions legislation – such as the Euro standards introduced in Europe in 1993 and subsequently adopted in other parts of the world – encourages the use of cleaner road vehicles. It does so by putting pressure on operators to accelerate vehicle replacement or to fit their existing vehicles with pollution reducing equipment. In Berlin, the share of compliant diesel-engine vehicles rose by 38% between 2006 and 2011 – largely because fleet operators installed diesel particle filters.

The cost of setting up the London (UK) LEZ was comparatively low because it made large-scale use of the city’s existing congestion charging infrastructure. Creating an LEZ using existing enforcement infrastructure – as in the London case – makes economic sense.

Environmental Traffic Control in Sydney, Australia

Analysis of Australia’s Sydney Coordinated Adaptive Traffic System (SCATS) has identified reductions of 15% in CO2, 13% in NOx and 15% in PM10 emissions from vehicles – as a result of reductions in travel times of 28% and traffic stops of 25%. Case Study: Sydney’s Coordinated Adaptive Traffic System

Noise Pollution

Noise pollution tends to attract less public concern than air pollution but it is a growing nuisance and poses a health hazard to people living on or near sites experiencing high levels of traffic noise. Traffic models for forecasting traffic noise impacts are emerging which take advantage of readily-available data on road geometry and the built environment.

CO2 and noise emissions often respond to similar solutions:

  • promoting the use of electric/hybrid rather than petrol or diesel engine vehicles
  • Low Emission Zones (LEZ) can contribute to reducing noise pollution – since vehicles complying with higher emissions standards are generally quieter than older ones
  • encouraging modal shift from road vehicles to public transport
  • enforcing existing speed limits and introducing lower limits in specific situations –for example, 32km/h zones in residential areas
Night-time Noise Abatement

Demonstrations in the West Midlands of England have shown that the use of night-time variable speed limits (VSLs) on sections of managed motorways near to residential areas can deliver worthwhile noise reductions without affecting journey times as much as in daytime.

Reduced Visual Intrusion

Cities can become cluttered with street furniture installed for traffic management and the safety of road users and pedestrians. The additional infrastructure (gantries, roadside cabinets and mounting posts) for ITS deployments – such as cameras for congestion charging enforcement, and on-street sensors for air quality monitoring – add to the clutter. This can be a serious issue in unspoilt rural areas and historic town centres – where tourism brings economic benefits.

There are ways to mitigate the visual impact of ITS equipment. For example:

  • a reduction in the number and size of gantries for tolling equipment is possible by rationalising the equipment required
  • satellite-based charging systems are now proven technology and will reduce the scale of physical tolling infrastructure
  • air quality information – needed for traffic management that can reduce pollution levels – is possible to collect using very small sensors or ‘motes’ that can be attached unobtrusively to buildings, existing street furniture, vehicles – and even on people

In time, it is possible (with good design and appropriate technology) that cooperative vehicle systems may reduce the need for invasive ITS installations on roads – since they will automatically collect, process and transfer data and traffic information between vehicles, the roadside and drivers.

Urban Environments

Transport links, the availability and quality of public transport, journey times and reliability are important factors for local communities and in deciding where to locate businesses.

When people and businesses relocate the more well-informed they are about transport options, the more likely they are to opt for well-connected locations. In North America, Australia and New Zealand, neighbourhood rating systems and journey planning which makes use of data from public transport operators, cyclists and pedestrians to highlight areas with good facilities.

ITS can also be used to manage and monitor environmental zones. For example, DMS and VMS can be used for signing the zone, especially if different access regimes apply to drivers at different times. ITS can also be used in air quality monitoring and in communicating the results to stakeholders. Example of these are:

  • Queensland, Australia – where the South East Queensland Air Quality model uses GIS to map current air quality and for forecasting in connection with land use and transport planning decisions. The GIS maps are also used as a communications tool, to inform about air quality and promote the need to improve it
  • Turin, Italy – where ITS is deployed for traffic management and public transport operations in response to pollution forecasts to reduce the severity of poor air quality.
Santander (Spain) – A Smart City

Santander, in Northern Spain, has a population of 180,000. It is deploying some 12,000 electronic sensors or ‘nodes’, fixed to buses and buildings, to measure a variety of parameters, such as noise, temperature, ambient light levels, carbon monoxide concentration, and the availability and location of parking spaces, for efficient city management:

  • repeater nodes on streetlights control their luminance and relay automatically notification of faults
  • residents receive streams of public information and can use smartphone applications to report hazards or incidents as they occur and keep track of the city’s response

Santander’s innovative approach has contributed to a decision by Spanish multinational transportation infrastructure investor, Ferrovial, to invest in the city and develop a Research Centre for Intelligent Cities – in parallel with the company’s cooperation agreement with the Massachusetts Institute of Technology (MIT).

Modal Shift – Greener Travel

ITS has been used as part of a coordinated approach to promote travel choices that will help reduce congestion and pollution in cities. It provides:

  • the tools to implement road pricing and congestion charging, in order to discourage or modify traffic demands
  • facilities to improve the attractiveness of alternatives such as public transport, car-sharing, carpooling, and cycling

Car pooling 

Car pooling (also known as ride-sharing) and car clubs are enjoying a boom, thanks to ITS technologies. ITS applications such as a car pool database (of drivers offering spare seats and potential passengers looking for a ride) – together with a user forum – can enable planned sharing of car journeys. Car pooling reduces individuals’ fuel, parking and toll costs – and in the USA, allows them use of dedicated high-occupancy vehicle (HOV) lanes. It helps to reduce traffic demand, cut emissions and relieve the pressure on parking. Employers can offer and promote schemes as an incentive to their workforces.

Car clubs provide members with the use of a car on an as-needed basis for specific journeys – delivering them savings on insurance, depreciation and road taxes. Local governments around the world are promoting schemes on their travel websites as making useful contributions to modal shift. Booking is by phone or internet. For some schemes, a member’s smartcard opens the vehicle and is used to process payment for use and fuel from the member’s account. Transport for London calculates that those driving fewer than 9,600km a year can save up to £3,500 as compared with owning a car.


Cycling is gaining popularity worldwide as an alternative travel mode, one that is attractive on personal and public health grounds. On busy urban roads, cyclists are vulnerable – particularly prone to collisions with heavy goods vehicles (HGVs) overtaking or making turning movements at road junctions. ITS-enabled protective systems being investigated include:

  • controlling access by HGVs in city centres – with electronic charging or access control and automated enforcement
  • fitting HGVs with video cameras that pick up images of cyclists at risk in the danger zone around the vehicles – and flash an audible or visual alert to their drivers
  • an identification system, with cyclists wearing a transponder (similar to an in-vehicle toll tag) that is read by an HGV’s on-board unit and again warns the driver


Reference sources

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