Road Journey Time Reliability

This measure shows the journey time reliability on key metropolitan routes during peak periods.

A NSW Government State Priority is to ensure that 90 percent of peak travel on key road routes is on time.

Journey time reliability on the road network is important to freight and impacts on the cost of moving goods in NSW. 

About the data

Dataset name: Roads Journey Time Reliability
Data owner: 
Greater Sydney Region, Transport for NSW
Coverage: Selected metropolitan routes managed by Transport for NSW.
Date range: July 2016 onwards
Frequency: Monthly

Description: This visualisation indicates the road journey time reliability for a series of Principal Transport Routes which cover the key movement corridors on the Sydney State Road network. 

The reported result reflects the percentage of journeys completed within the reporting period that fall below the threshold. The threshold is defined as 17 percent above the average travel time for each link at 15 minute intervals during weekday peak periods. Weighting is applied based on the length of the road link to account for the relative importance of a link to the overall route.

Transport for NSW is currently using a number of new travel time data sources to calculate Journey Time Reliability across Sydney to improve accuracy.

As these new sources use different methods to collect data the Journey Time Reliability results are currently under review.

When the data sources have been recalibrated to ensure consistency Transport for NSW will begin publishing the data.

Definitions
  • Journey Time Reliability (JTR) is defined as the percentage of journeys completed within an allowable excess of 17% of the standard journey time during specified weekday peak periods. The threshold is defined as 117% of the average travel time for each road link at each 15 minute interval across the peak periods.
  • On time is defined as no more than 5 minutes above average travel time on a 30 minute journey during the combined AM and PM peak periods. 
  • A link is defined as a segment of the road, usually between two intersections. 
  • A route is comprised of multiple links. 
    Limitations 
    • Travel times are collected at 15 minute intervals.
    • The lack of traffic collection stations at over 50% of Principal Transport Routes means that travel times cannot be volume weighted to show the relative importance of a link to the overall network.
    • Origin destination data is not available via Google Travel Time data.