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Figure 3B-12. Examples of Lane Reduction Markings
This figure illustrates three examples of lane reduction markings.
The figure shows three horizontal roadways, examples (a), (b),
and (c). For all examples, the roadway is shown with several measurements.
The distance L is noted as length in meters or feet and is shown
as the length of the taper from two lanes to one in the eastbound
direction. The speed S is noted as the posted, 85th percentile or
statutory speed in km/h or mph. The distance W is noted as the offset
in meters and is shown as the width of the lane that is eliminated
via the eastbound taper. The distance d is noted as the advance
warning distance (see Section 2C.05) and is shown as the distance
from the lane reduction warning sign to the start of the taper from
two lanes to one in the eastbound direction. The lane reduction
sign is shown as a diamond-shaped yellow sign with a black border
and legend. It shows a thick, vertical straight line on the left;
a thick, vertical line on the right that angles toward the left
half way up; and a thin, short vertical dotted line between them
that is the length of the vertical section of the line on the right.
Notes state See Section 3D.04
for delineator spacing. For speeds 70 km/h (45 mph) or more: L =
0.62 WS (L = WS). For speeds less than 70 km/h (45 mph): L = WS2/155
(L = WS2/60).
- Example (a) shows a roadway that reduces from three lanes to
two lanes. The figure shows a roadway with one lane traveling
west and two lanes (reducing to one lane) traveling east. The
lanes in opposing directions are shown separated by a solid double
yellow line. The two eastbound lanes are shown separated from
each other by a broken white line. Two eastbound lanes are shown
beginning on the left of the figure and then reducing to one lane
on the right. A solid white line is shown on the outside edge
of the eastbound pavement, starting at the lane reduction warning
sign and ending beyond the end of the lane reduction taper.
- Example (b) shows a horizontal roadway that reduces from four
lanes to three lanes. The figure shows a roadway with two westbound
lanes and two lanes (reducing to one lane) in the eastbound direction.
The lanes in opposing directions are shown separated by a solid
double yellow line. The lanes in the same direction are shown
separated from each other by a broken white line. Two eastbound
lanes are shown beginning on the left of the figure and then reducing
to one lane on the right. A solid white line is shown on the outside
edge of the eastbound pavement, starting at the lane reduction
warning sign and ending beyond the end of the lane reduction taper.
Delineators are shown next to the right side of the roadway in
the eastbound direction along the lane reduction taper.
- Example (c) shows a horizontal roadway that reduces from four
lanes to two lanes. The figure shows a roadway with one lane (increasing
to two lanes) in the westbound direction and two lanes (reducing
to one lane) in the eastbound direction. The lanes in opposing
directions are shown separated by a solid double yellow line.
The lanes in the same direction are shown separated from each
other by a broken white line. One westbound lane is shown beginning
on the right side of the figure and increasing to two. The solid
double yellow line is shown changing from straight to slightly
diagonal to the south to accommodate the second westbound lane.
Two eastbound lanes are shown beginning on the left of the figure
and then reducing to one lane on the right. A solid white line
is shown on the outside edge of the eastbound pavement, starting
at the lane reduction warning sign and ending beyond the end of
the lane reduction taper. Delineators are shown next to the right
side of the roadway in the eastbound direction along the lane
reduction taper.
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