SC-Coppell MSN-CS 9809173B-12 Combination Lone and Center Line Markings for Unique
Applioafions
It is sometimes necessary to use nmrkings in certain combinatio~
not previously described for special applications intended to impro%
traffic operations.
For reversible lane markings, each edge of the lane shall be markt
by the use of a double normal broken yellow line with the gaps ar,
segments adjacent to one another. Signs and/or signals shall be used
supplement the pavement rflarkings (fig. 3-1, page $B-3).
A two-way left turn lane is a lane reserved in the center of
highway for exclusive use of left turn vehicles and shall not be used f,
passing and over ng travel by a d ver to m ea le
turn. The lane may be used by drivers making the left turn in eith,
direction. A two-way left turn lane shall be marked by a single dire
tion, no-passing marking on each edge of the lane and pavement mar]
lane highway where them are two lanes of through ~affi¢ in each dim
tion. Signs should be used with the pavement markings (sec. 2B-lC~
required$¥mb°l markingSsigns, ss shown in fi~ure 3-§a may be used in addition to ti'
lIB-IS Approach to -n Oh-trnefion
Pavement nmrkings sl~dl be u~l to guide ~affic on the approach
fixed obstructions within a paved roadway. An obstruction may be ~
lecat~! that ali traffic must keep to the right of it, or it may !:
between two lance of ta'affic moving in the sMne direction. The marl
ings in either ease must be designed to gnide traffic away fi.om
obstruction. The use of ehanneli~ing lines or no-paseing markings ~
generally effective. Obstruction approach m.~s for bridgs support.
refugs islands, median islands, and channeli~.ation islands shall consi~
of a diagonal line, or lines, extending from the center line or tbe
line to a point 1 or 2 feet to the right side, or to both sides, of ti:
approach end of the obstruction {fig. 3-13).
The length of the diagonal markings (taper length) should be con
puted by the formula L = WS for freeways, expressways and all oth~
roadways having a posted speed of 45 m.p.h, or greater. The formu]
L = WS~/60 should be used to compute taper length on urban, reside~
tial, and other streets where the posted speeds are 40 m.p.h, or les:
Under both formulas, L equals the taper length in feet, W the width
the offset in feet, ~nd $ the off-p~k 85 percenffie speed in miles I~
hour. The minimum taper length shall be 100 feet in urban areas an
200 feet in rural areas.
TX 3B-18 (Rev. No..