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Chapter 4O. Traffic Control Signals for One-Lane, Two-Way Facilities

§4O.01 Application of Traffic Control Signals for One-Lane, Two-Way Facilities

Support

01. A traffic control signal at a narrow bridge, tunnel, or roadway section that is not of sufficient width for two opposing vehicles to pass is a special signal that alternates which direction of travel is permitted to proceed.

02. Temporary traffic control signals (see Sections 4D.11 and 6L.01) are the most frequent application of traffic control signals for one-lane, two-way facilities.

Guidance

03. Sight distance across or through the one-lane, two-way facility should be considered as well as the approach speed and sight distance approaching the facility when determining whether traffic control signals should be installed.

Option

04. At a narrow bridge, tunnel, or roadway section where a traffic control signal is not justified under the conditions of Chapter 4C, a traffic control signal may be used if gaps in opposing traffic do not permit the flow of traffic through the one-lane section of roadway.

§4O.02 Design of Traffic Control Signals for One-Lane, Two-Way Facilities

Standard

01. The provisions of Chapters 4D through 4G shall apply to traffic control signals for one-lane, two-way facilities, except that:

  • A. The durations of the red clearance intervals shall be adequate to clear the one-lane section of conflicting vehicles; and
  • B. Adequate means, such as interconnection, shall be provided to prevent conflicting signal indications, such as green and green, at opposite ends of the section.

§4O.03 Operation of Traffic Control Signals for One-Lane, Two-Way Facilities

Guidance

01. Traffic control signals at one-lane, two-way facilities should operate in a manner consistent with traffic requirements.

02. Adequate time should be provided to allow traffic to clear the narrow facility before opposing traffic is allowed to move. Engineering judgment should be used to determine the proper timing for the signal.

Standard

03. When in the flashing mode, the signal indications shall flash red.