Lane-by-lane modelling of unequal lane use and flares at roundabouts and signalised intersections: the SIDRA solution

摘要

This paper has been prepared in response to two articles recently published in this journal, by Chard and by Simmonite and Moore. These articles address prediction problems associated with the approach method of traffic modelling which lumps together traffic in individual lanes of an intersection approach. Chard demonstrates by means of case-studies that '(the ARCADY model) can take no account of either unused or unequally used lanes or flared sections on roundabout entry approaches. ARCADY is, in fact, completely 'blind' to such occurrences, and as a consequence may produce hopelessly optimistic predictions.' Chard describes a methodology to correct for this problem, but recommends that 'a new by lane entry' model rather than the current, and possibly now outdated, 'by approach entry' model (should be developed in the longer term)'. Indeed, the corrective method appears to be very inefficient, as it would require repeated calculations for each possible demand pattern and lane discipline design.