tailieunhanh - Design Manual Metric 2009 Part 9

Tham khảo tài liệu 'design manual metric 2009 part 9', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | movement displays. Program this display as an overlap to both the left-turn phase and the adjacent through phase. e Two-lane right-turn phasing. Two-lane right-turn phasing can be used for an extraordinarily heavy right-turn movement. They can cause operation problems when right turn on red is permitted at the intersection. Limited sight distance and incorrect exit lane selection are pronounced and can lead to an increase in accidents. In most cases a single unrestricted right turn only lane approach with a separate exit lane will carry a higher traffic volume than the two-lane right-turn phasing. f Phasing at railroad crossings. Railroad preemption phasing is required at all signalized intersections when the nearest rail of a railroad crossing is within 61m of the stop bar of any leg of the intersection unless the railroad crossing is rarely used or is about to be abandoned. Preemption for intersections with the railroad crossing beyond 61 m from the intersection stop line is only considered when the queue on that approach routinely occupies the crossing. Contact the railroad company to determine if this line still actively carries freight or passengers. Railroad preemption has two distinct intervals the clearance interval before the train arrives and the passage interval when the train is crossing the intersection leg. During the clearance interval all phases are terminated and the movement on the railroad crossing leg is given priority. When this movement has cleared the crossing it is then terminated. During the passage interval the traffic signal cycles between the movements not affected by the train crossing. See Figure 850-7 for an example of railroad preemption phasing. Arranging for railroad preemption requires a formal agreement with the railroad company. The region s Utilities Engineer s office handles this transaction. Contact this office early in the design stage as this process can be time consuming and the railroad company might require some .