VACANCY INTERNSHIP PROJECT We are looking for students interested in carrying out their internship or master thesis at DAT.Mobility Modelling junction delays in large scale strategic transport models It is well known that the accuracy of strategic transport models on urban networks can be improved by adding a junction modelling component to the traffic assignment stage. To this end, junction modelling modules are widely available (e.g. the US Highway Capacity Manual (TRB, 2000), the German HBS (FGSV, 2015), the UK Arcady/Picady methodologies (TRL Software) or the junction modelling component in the Dutch OmniTRANS transport planning software (Bezembinder, 2017). Problem description Although adding junction modelling increases accuracy, it also has its downsides. Firstly, the input requirements for each of these methodologies are high: for each junction, its type, lane configuration of all incoming and outgoing arms and signaling scheme (if any) need to be defined (as illustrated below).
Secondly, adding junction modelling has a negative effect on convergence of the traffic assignment model as cost functions become inseparable and (potentially) asymmetric, which makes it much harder (if not impossible) to equilibrate (see e.g: Muijlwijk (2012)). In practice, this means that the due to additional junction modelling calculations, and especially the decreased convergence properties (stability of the solution), calculation times of the assignment model may increase significantly. To (partly) overcome these downsides, two more simplistic methods can be applied. Either the junction delays are considered fixed (i.e.: invariant to flows) or average junction delays are calculated on the node level using node delay functions (i.e.: aggregated over all turning movements). Assignment Research goal is to determine which (combination of) junction modelling type is most suitable for application in strategic transport models. Research roughly consists of the following steps: 1. Review the OmniTRANS junction modelling 2.0 methodology (Bezembinder 2017) 2. Literature research on fixed delays and node delay functions 3. Implementation of fixed delays and node delay functions in theoretical networks and NRM‐west model 4. Comparison on accuracy, effect on convergence, calculation time, … Research group / information DAT.Mobility Deventer Luuk Brederode (DAT.Mobility/Delft University) / Erwin Bezembinder (Windesheim/ UTwente) When interested in this internship assignment, please contact Luuk Brederode (lbrederode@dat.nl).