While the focus has traditionally been on delivering more efficient (faster) journeys, research now confirms that reliable journeys are often more important to transport users than faster ones. This means that travelling at slower average speeds, but with greater certainty of arriving on time is preferable to travel contingency-time being built in for unexpected events.
For transport professionals around the world, this represents an important paradigm shift in transport planning – a move from more efficient to more reliable transport networks. Developing a solid understanding about the specific influencers and their effects is the first step in addressing this new challenge.
Preparing for the Unexpected
Poor travel reliability is driven by what are known as ‘non-recurrent’ events. These are unexpected events that network and transport users have not anticipated and have not been equipped to deal with, such as freak weather, accidents and road works, which cause sudden changes in capacity and demand.
These events have immediate localised impacts but can also influence cascading reliability issues, both spatially within the directly affected network and across other modal networks such as bus, train and car transport. The impacts depend on the type, duration and location of the event.
How do we respond to these events and mitigate the impacts to make our transport networks and systems more resilient? As with any type of risk, we aim to reduce its likelihood and significance by identifying and implementing appropriate strategies and interventions.
In the following studies, WSP worked with clients to plan for more resilient networks. This was achieved by developing targeted operational planning and transport systems that identify issues faster, reduce response times and manage more effective network and capacity. A key enabler for this outcome is our world-shaping time management tool – technology.
Defining What Journey Time Reliability Is in Western Australia
Increasing reliability requires defining a metric as the first step towards developing a fully-integrated management system and more comprehensive network intelligence to guide the faster identification of, and response to, non-recurrent events.
An element of our work with Main Roads Western Australia was to help define a reliability metric which takes into account of network structure and network management objectives.
The metric will be used alongside other performance indicators to report periodically on the performance of the strategic road network and to evaluate the impact of reliability focussed policy objectives and infrastructure improvements.
Network management and optimisation teams will also use the performance metric to identify and cost reliability hotspots which will form the foundation for the identification of corridor and network improvements.
In addition to the definition of the performance metric we conducted an audit of the current Network Performance Monitoring System (NetPReS) and the associated system architecture providing recommendations on enhancements to support better reliability performance monitoring. The ultimate aim being to develop a comprehensive reliability monitoring program with predictive capability.