This paper applied an operational field study and an analytical process to recommend roundabout exit sign loading conditions, that is, the number of destination names or route numbers. The available time for drivers to detect and read roundabout exit signing is affected by both exit sign placement and various operational conditions, for example, merge and lane-change requirements. It was therefore necessary to develop sign information load requirements in the context of competing roundabout driving task demands, for example, merging, lane changing, and exiting. Field study results indicated that operational speeds closely correlated to the R (sub 4) radius design speed. Sign information lead time was determined from the operational speed and detection distance to a roundabout exit sign. The required time to read sign components, (words and numbers), and to make the appropriate choice decisions was derived. Available sign reading and decision time in roundabouts was then based on the difference between total sign information lead time and the time consumed by the competing tasks. (Author/publisher) For the covering entry of this conference, please see ITRD abstract no. E213531.
Samenvatting