SIDRA modelling in action

A recent example of ViaStrada’s SIDRA capabilities is Megan’s modelling of two signalised intersections in New Plymouth, as part of the Transport Choices programme. ViaStrada has identified several challenges in modelling filter turning across cycleways and has developed methods to deal with these.

Instead of having red arrows for conflicting traffic, the intersections currently provide partial pedestrian protection via late starts to all traffic on approaches with conflicting movements (i.e. the through traffic is held back initially as well). The approach to modelling pedestrian effects in the base model is to apply additional late starts and additional start losses to affected movements.

The proposed options involved separated cycleways on the intersection approaches, which were modelled as having full protection. Several different phasing scenarios were investigated, including replacing existing split approach operation on the side streets with one phase with filter right turns, and lengthening a critical right turn bay where demand currently frequently exceeds supply. These changes offset the reduction in LOS by introducing the protected cycle movements.

After the initial modelling using full protection for cyclists was undertaken, a programme-wide decision was made to provide an initial period of protection to cyclists followed by left turners being allowed to “filter” across the cycle movement (i.e. they wait for a gap in the cyclists and turn when it is safe to do so). This is expected to improve LOS for cyclists, as well as efficiency for left turners, which is particularly important where there are shared left turn and through lanes.

SIDRA INTERSECTION is an advanced micro-analytical traffic evaluation software developed by SIDRA Solutions and used by transport professionals in 90+ countries across the globe. This powerful tool can be used for the design and evaluation of single intersections and networks of intersections.

The latest version, SIDRA INTERSECTION 9.1 released late last year includes many new features, model enhancements and user interface improvements.

SIDRA’s abilities include:
•    modelling of different intersection control options (priority-control, roundabout, signals)
•    analysis of different traffic signal scenarios (layouts, phasing)
•    assessment of networks of multiple adjacent intersections

As the official NZ reseller and trainer for SIDRA, we can help! Please get in touch with us by emailing to find out more about how SIDRA Solutions’ powerful modelling software can help your business.