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

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Performance Measures

The need for Performance Measures in Road Network Operations (RNO) is widely recognised. They have been a topic of discussion for many years but it is only recently that ITS devices provided the data necessary to support performance measures and their importance in RNO. (See  Performance Indicators)

ITS can play a major role in performance measurement and will be useful to countries that do not already have strong road network performance management programmes. Performance management is important to ensure that:

  • the transport agency achieves its goals and objectives
  • systems deployed are cost effective
  • managers and operators get feedback so they can assess how effective their actions have been and what changes may be needed to their plans
  • the return on investment is positive in terms of road-user benefits
  • performance measurements are consistent across the country, or even regional group of nations, if appropriate
  • performance measurements are increasingly outcome-based rather than output (production)

Possible categories of performance measures relevant to RNO include:

  • performance of the strategic highways viewed from the operational perspective (not strictly physical condition) – for example, measures of journey time reliability
  • traffic incidents – collisions/incident rates and the incidence of secondary collisions
  • incident severity – for example incident duration, numbers killed and seriously injured
  • traffic congestion – for example an ITS-based measure reflecting accumulated traffic delays
  • on-road mobile source emissions – using environmental sensors as the data collection mechanism
  • freight movements on strategic highways
Examples of RNO Performance Measures

Traffic Incident Management

A USDOT scanning tour of four European nations (England, Germany, Sweden and the Netherlands) in 2005 found a strong interest in performance-based Traffic Incident Management. Performance measures are applied in various ways, to monitor:

  • progress in reducing fatalities and serious injuries (England)
  • response time as the basis for location of fire station and Emergency Management Services - and for resource allocation on a local or regional basis (Germany and the Netherlands)
  • response time as the basis for towing and recovery contracts (the Netherlands)

Levels of Service to Road users

The following are being considered for the USA:

  • travel-time reliability (buffer index) – the buffer index is the additional time that must be added to a trip to ensure that travellers making the trip will arrive at their destination at, or before, the intended time, 95% of the time
  • extent of congestion – spatial (also measurable by time) - miles of roadway within a predefined area and time period, for which average journey times are 30% longer than unconstrained journey times
  • incident duration – the time elapsed from the notification of an incident until all evidence of the incident has been removed from the incident scene
  • customer satisfaction – a qualitative measure of customers’ opinions related to the roadway management and operations services provided in a specified region


Reference sources

American Trade Initiatives (2006) Traffic Incident Response Practices in Europe Report No. FHWA-PL-06-002, US Federal Highway Administration, Washington D.C.