VLC in association with VIAE Consulting was engaged by Transport for NSW to forecast travel demand impacts of options to upgrade the Great Western Highway west of Katoomba 


Client requirements

VLC advised TfNSW on the appropriate modelling framework to represent travel across the Blue MountainsThe corridor is characterised by steep grades, seasonal variation in congestion and high proportions of heavy vehicle traffic so a bespoke modelling system was required to reflect all aspects. VLC was required to work closely with the TfNSW project team, comprising TfNSW staff and a range of other consultants, to support option short-listing and assessment. 


Delivered outcome

VLC developed and integrated two models to produce forecasts under various project scenarios and across different day types – weekday and busy weekends. The core model is the Regional Travel Model (RTM) in Emme which models how changes in the road network influence the number, distribution and mode choices of travellers across NSW. The RTM is supported by a newly developed operational model (OTM) in AIMSUN that analysed variation in travel speeds through the course of an average weekday and a busy weekend afternoon. OTM travel speeds were fed back into the RTM for final project results. 

VLC developed a range of bespoke outputs to support project planning: 

  • Network KPIs from both models (travel time savings, vehicle kilometres, intersection queues, etc.) to feed into the core economic appraisal 
  • Road volumes by spatially defined links to inform the calculation of noise and amenity benefits 
  • A methodology and results report that summarised key impacts of the project options (end-to-end journey time savings for cars and trucks, and the degree of induced traffic on the highway) 
  • High-level travel flows for cars and trucks to drive the optioneering among different ramp access configuration options 
  • Analysis of telecommunication handset travel data, delay data and road incident data to identify how travel patterns and delay outcomes vary on different types of days through the year 
  • Weighted-average travel cost matrices for passenger and freight travel to inform Computable General Equilibrium modelling of NSW.