Previous research has shown that drivers often fail to yield to cyclists who have the right of way, particularly when turning right. This finding was confirmed in a driving simulator study. To determine whether this is a systematic issue related to the type of attention required by road users, a systematic investigation was conducted.

When travelling through an intersection, different trajectories intersect. Various rules determine who has priority, resulting in different attention targets that road users must monitor to proceed safely and in accordance with the rules. For example, when going straight on a main road, the only attentional requirements on the driver are to monitor to the left and right for pedestrians who might want to cross on the zebra crossing. On a subordinate road in the same situation, the driver also needs to check for cross traffic from the left and from the right.  

The attention targets at intersections can be classified as either ‘overt’ (visible via signs, road markings, etc.) or ‘covert’ (unmarked and have to be remembered, e.g., the need to check ‘over the right shoulder’ for cyclists and pedestrians when a driver is turning right from a main road). Additionally, they can be categorised as ‘same-mass’ (for partners in an encounter) or ‘lower-mass’ (as in the turning-right example where the cyclist has lower mass), and as ‘required’ (when one must yield to superior traffic streams) or ‘not required’ (when one has priority).