Application of Lane-Use Control Signals
Support:
Lane-use control signals are special overhead signals that permit
or prohibit the use of specific lanes of a street or highway or
that indicate the impending prohibition of their use. Lane-use control
signals are distinguished by placement of special signal faces over
a certain lane or lanes of the roadway and by their distinctive
shapes and symbols. Supplementary signs are sometimes used to explain
their meaning and intent.
Lane-use control signals are most commonly used for reversible-lane control, but are also used in nonreversible freeway lane applications.
Guidance:
An engineering study should be conducted to determine whether a
reversible-lane operation can be controlled satisfactorily by static
signs (see Section 2B.25)
or whether lane-use control signals are necessary. Lane-use control
signals should be used to control reversible-lane operations if
any of the following conditions are present:
Option:
Lane-use control signals also may be used for reversible-lane operations
at toll booths. They may also be used if there is no intent or need
to reverse lanes, including:
Meaning of Lane-Use Control Signal Indications
Standard: The meanings of lane-use control signal indications are as follows:
Pavement markings (see Section 3B.03) shall be used in conjunction with reversible-lane control signals.
Figure 4J-1 Left-Turn Lane-Use Control Signals
Design of Lane-Use Control Signals
Standard:
All lane-use control signal indications shall be in units with rectangular
signal faces and shall have opaque backgrounds. Nominal minimum
height and width of each DOWNWARD GREEN ARROW, YELLOW X, and RED
X signal face shall be 450 mm (18 in) for typical applications.
The WHITE TWO-WAY LEFT-TURN ARROW and WHITE ONE WAY LEFT-TURN ARROW
signal faces shall have a nominal minimum height and width of 750
mm (30 in).
Each lane to be reversed or closed shall have signal faces with a DOWNWARD GREEN ARROW and a RED X symbol.
Each reversible lane that also operates as a two-way or one-way left-turn lane during certain periods shall have signal faces that also include the applicable WHITE TWO-WAY LEFT-TURN ARROW or WHITE ONE WAY LEFT-TURN ARROW symbol.
Each nonreversible lane immediately adjacent to a reversible lane shall have signal indications that display a DOWNWARD GREEN ARROW to traffic traveling in the permitted direction and a RED X to traffic traveling in the opposite direction.
If in separate signal sections, the relative positions, from left to right, of the signal indications shall be RED X, YELLOW X, DOWNWARD GREEN ARROW, WHITE TWO-WAY LEFT-TURN ARROW, WHITE ONE WAY LEFT-TURN ARROW.
The color of lane-use control signal indications shall be clearly visible for 700 m (2,300 ft) at all times under normal atmospheric conditions, unless otherwise physically obstructed.
Lane-use control signal faces shall be located approximately over the center of the lane controlled.
If the area to be controlled is more than 700 m (2,300 ft) in length, or if the vertical or horizontal alignment is curved, intermediate lane-use control signal faces shall be located over each controlled lane at frequent intervals. This location shall be such that road users will at all times be able to see at least one signal indication and preferably two along the roadway, and will have a definite indication of the lanes specifically reserved for their use.
All lane-use control signal faces shall be located in a straight line across the roadway approximately at right angles to the roadway alignment.
The bottom of the signal housing of any lane-use control signal face shall be at least 4.6 m (15 ft) but not more than 5.8 m (19 ft) above the pavement grade.
On roadways having intersections controlled by traffic control signals, the lane-use control signal face shall be located sufficiently far in advance of or beyond such traffic control signals to prevent them from being misconstrued as traffic control signals.
Option:
In areas with minimal visual clutter and with speeds of less than
70 km/h or less than 40 mph, lane-use control signal faces with
nominal height and width of 300 mm (12 in) may be used for the DOWNWARD
GREEN ARROW, YELLOW X, and RED X signal faces, and lane-use control
signal faces with nominal height and width of 450 mm (18 in) may
be used for the WHITE TWO-WAY LEFT-TURN ARROW and WHITE ONE-WAY
LEFT-TURN ARROW signal faces.
Other sizes of lane-use control signal faces larger than 450 mm (18 in) with message recognition distances appropriate to signal spacing may be used for the DOWNWARD GREEN ARROW, YELLOW X, and RED X signal faces.
Nonreversible lanes not immediately adjacent to a reversible lane on any street so controlled may also be provided with signal indications that display a DOWNWARD GREEN ARROW to traffic traveling in the permitted direction and a RED X to traffic traveling in the opposite direction.
The signal indications provided for each lane may be in separate signal sections or may be superimposed in the same signal section.
Operation of Lane-Use Control Signals
Standard:
All lane-use control signals shall be coordinated so that all the
signal indications along the controlled section of roadway are operated
uniformly and consistently. The lane-use control signal system shall
be designed to reliably guard against showing any prohibited combination
of signal indications to any traffic at any point in the controlled
lanes.
For reversible-lane control signals, the following combination of signal indications shall not be shown simultaneously over the same lane to both directions of travel:
A moving condition in one direction shall be terminated either by the immediate display of a RED X signal indication or by a YELLOW X signal indication followed by a RED X signal indication. In either case, the duration of the RED X signal indication shall be sufficient to allow clearance of the lane before any moving condition is allowed in the opposing direction.
Whenever a DOWNWARD GREEN ARROW signal indication is changed to a WHITE TWO-WAY LEFT-TURN ARROW signal indication, the RED X signal indication shall continue to be displayed to the opposite direction of travel for an appropriate duration to allow traffic time to vacate the lane being converted to a two-way left-turn lane.
If an automatic control system is used, a manual control to override the automatic control shall be provided.
Guidance:
The type of control provided for reversible-lane operation should
be such as to permit either automatic or manual operation of the
lane-use control signals.
Standard:
If used, lane-use control signals shall be operated continuously,
except that lane-use control signals that are used only for special
events or other infrequent occurrences and lane-use control signals
on nonreversible freeway lanes may be darkened when not in operation.
The change from normal operation to nonoperation shall occur only
when the lane-use control signals display signal indications that
are appropriate for the lane use that applies when the signals are
not operated. The lane-use control signals shall display signal
indications that are appropriate for the existing lane use when
changed from nonoperation to normal operations. Also, traffic control
devices shall clearly indicate the proper lane use when the lane
control signals are not in operation.
Support:
Section 2B.25 contains
additional information concerning considerations involving left-turn
prohibitions in conjunction with reversible-lane operations.
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Location: before an intersection. Lane Use Control signs are installed before intersections where drivers can only go in the direction indicated by the sign for their traffic lane.
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