Right turns at signalised intersections

Hi All,

My question is regarding how the iRAP model considers right turns (left turns in countries that drive on the right) at signalised intersections, and hence how these should be coded. There are essentially two ways to deal with right turns at signalised intersections: 1) Control right turns (red movement in below image) so that they are not allowed when opposing through movement is given a green signal (blue movement in below image), or 2) allow what we call “filter right turn” movements that allow the right turning driver to select a gap in the opposing traffic flow when the opposing through movement is given a green signal. In South Australia (where I am from), at intersections that allow filter right turns, these account for (on average) half of all fatal and serious injury crashes associated with intersection movements. Hence, considering whether filter right turns are allowed or not has a major impact on safety outcomes.

Does the iRAP model consider that filter right turns can be allowed or not when coding the intersection type as a signalised intersection, or is this differentiation not made? And (more importantly) can the banning or allowance of filter right turns be coded into iRAP?

Cheers, Chris.

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