Information point and saturation flow at signalized intersections

This paper introduces an information point factor and attempts to identify how it affects saturation flow and their relationship at signalized intersections. An information point is defined as any object, structure, or activity located outside of a traveling vehicle that can potentially attract the visual attention of the driver. Saturation flow rates are studied at three pairs of signalized intersections in Toledo, Ohio, USA. Each pair of intersections consists of one intersection with a high number of information points and one intersection with a low number of information points. Study results reveal that, for each pair of intersections, the one with high information points has a lower saturation flow rate than the one with low information points. A statistical analysis shows that the differences are significant. Based on the saturation flow data of the paired intersections, information point effect models are developed and presented in this paper.