902.15 Traffic Control Signals for One-Lane, Two-Way Facilities (MUTCD Chapter 4O)
902.15.1 Application of Traffic Control Signals for One-Lane, Two-Way Facilities (MUTCD Section 4O.01)
Support. 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.
Temporary traffic control signals (see EPG 902.4.11 and EPG 616.12.1) are the most frequent application of traffic control signals for one-lane, two-way facilities.
Guidance. 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. At a narrow bridge, tunnel, or roadway section where a traffic control signal is not justified under the conditions of EPG 902.3, 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.
902.15.2 Design of Traffic Control Signals for One-Lane, Two-Way Facilities (MUTCD Section 4O.02)
Standard. The provisions of EPG 902.4 through EPG 902.7 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.
902.15.3 Operation of Traffic Control Signals for One-Lane, Two-Way Facilities (MUTCD Section 4O.03)
Guidance. Traffic control signals at one-lane, two-way facilities should operate in a manner consistent with traffic requirements.
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. When in the flashing mode, the signal indications shall flash red.