Summer 2017 Original Version – Winter 2013 The Ohio LTAP Center Page | 1 of 8 http://www.dot.state.oh.us/LTAP The Ohio Manual of Uniform Traffic Control Devices (OMUTCD) provides standards and guidelines for the use of traffic signs, pavement markings, traffic signals, and other traffic control devices in our state. The Manual applies to all roads open to public travel in Ohio. This RON Technical Update highlights some of the OMUTCD standards and guidelines regarding use of horizontal alignment warning signs [see Figure 2C-1 on page 2]. The primary source for this information is OMUTCD Part 2 – Signs; Chapter 2C – Warning Signs and Object Markers. All chapter and section references in this document refer to the OMUTCD. This brief Technical Update is not intended to be used as a substitute for the actual Manual. Please refer to the current edition of the OMUTCD for the complete text and details. Horizontal Alignment Warning Signs (See OMUTCD Section 2C.06) A variety of horizontal alignment warning signs (see Figure 2C-1), pavement markings (see Chapter 3B), and delineation (see Chapter 3F) can be used to advise motorists of a change in the roadway alignment, such as a curve or turn. Uniform application of these traffic control devices with respect to the amount of change in the roadway alignment conveys a consistent message establishing driver expectancy and promoting effective roadway operations. The design and application of horizontal alignment warning signs to meet those requirements are addressed in Sections 2C.06 through 2C.15 of the OMUTCD. Standard: In advance of horizontal curves on freeways, on expressways, and on roadways with more than 1,000 AADT [average annual daily traffic] that are functionally classified as arterials or collectors, horizontal alignment warning signs shall be used in accordance with Table 2C-5 based on the speed differential between the roadway’s posted or statutory speed limit or 85th-percentile speed, or the prevailing speed on the approach to the curve, and the horizontal curve’s advisory speed. [see Table 2C-5 on page 3] [see page 5 – “How is the advisory speed determined?”] Option: Horizontal alignment warning signs may also be used on other roadways or on arterial and collector roadways with less than 1,000 AADT based on engineering judgment. Use of Horizontal Alignment Warning Signs
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Use of Horizontal Alignment Warning Signs of Horizontal...Alignment/Advisory Speed sign shall only be used as a supplement to the advance Horizontal Alignment warning sign. If used,
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Summer 2017 Original Version – Winter 2013 The Ohio LTAP Center P a g e | 1 of 8 http://www.dot.state.oh.us/LTAP
The Ohio Manual of Uniform Traffic Control Devices (OMUTCD)
provides standards and guidelines for the use of traffic signs,
pavement markings, traffic signals, and other traffic control
devices in our state. The Manual applies to all roads open to
public travel in Ohio.
This RON Technical Update highlights some of the OMUTCD
standards and guidelines regarding use of horizontal alignment
warning signs [see Figure 2C-1 on page 2]. The primary source
for this information is OMUTCD Part 2 – Signs; Chapter 2C –
Warning Signs and Object Markers. All chapter and section
references in this document refer to the OMUTCD.
This brief Technical Update is not intended to be used as a substitute for the actual Manual.
Please refer to the current edition of the OMUTCD for the complete text and details.
Horizontal Alignment Warning Signs (See OMUTCD Section 2C.06) A variety of horizontal alignment warning signs (see Figure 2C-1), pavement markings (see Chapter 3B), and delineation (see Chapter 3F) can be used to advise motorists of a change in the roadway alignment, such as a curve or turn. Uniform application of these traffic control devices with respect to the amount of change in the roadway alignment conveys a consistent message establishing driver expectancy and promoting effective roadway operations. The design and application of horizontal alignment warning signs to meet those requirements are addressed in Sections 2C.06 through 2C.15 of the OMUTCD. Standard:
In advance of horizontal curves on freeways, on expressways, and on roadways with more
than 1,000 AADT [average annual daily traffic] that are functionally classified as arterials or
collectors, horizontal alignment warning signs shall be used in accordance with Table 2C-5
based on the speed differential between the roadway’s posted or statutory speed limit or
85th-percentile speed, or the prevailing speed on the approach to the curve, and the
horizontal curve’s advisory speed. [see Table 2C-5 on page 3] [see page 5 – “How is the advisory speed determined?”]
Option:
Horizontal alignment warning signs may also be used on other roadways or on arterial and
collector roadways with less than 1,000 AADT based on engineering judgment.
The Turn (W1-1) sign or the Curve (W1-2) sign may be combined with the Advisory Speed
(W13-1P) plaque (see Section 2C.08) to create a combination Turn /Advisory Speed (W1-1a)
sign or combination Curve/Advisory Speed (W1-2a) sign (see Figure 2C-1).
The combination Horizontal Alignment/Advisory Speed sign may be used to supplement the
advance Horizontal Alignment warning sign and Advisory Speed plaque based upon an
engineering study.
Standard:
If used, the combination Horizontal Alignment/Advisory Speed sign shall not be used alone
and shall not be used as a substitute for a Horizontal Alignment warning sign and Advisory
Speed plaque at the advance warning location. The combination Horizontal
Alignment/Advisory Speed sign shall only be used as a supplement to the advance
Horizontal Alignment warning sign. If used, the combination Horizontal
Alignment/Advisory Speed sign shall be installed at the beginning of the turn or curve.
Illustrated example – based on OMUTCD Figure 2C-2 and Section 2C.10
If used, the combination Horizontal Alignment/ Advisory Speed sign (W1-1a or W1-2a):
shall not be used alone;
shall not be used as a substitute for a Horizontal Alignment warning sign (W1-1 or W1-2) and Advisory Speed plaque (W13-1P) at the advance warning location;
shall only be used as a supplement to the advance Horizontal Alignment warning sign; and
shall be installed at the beginning of the turn or curve.
[please see also Section 2C.07, Figure 2C-1, and the complete version of Figure 2C-2]
Guidance:
The advisory speed displayed on the combination Horizontal Alignment/Advisory Speed sign
should be based on the advisory speed for the horizontal curve using recommended engineering
Summer 2017 Original Version – Winter 2013 The Ohio LTAP Center P a g e | 7 of 8 http://www.dot.state.oh.us/LTAP
“Who can I call if I have questions?” Questions about traffic signs may be directed to Jim Roth, P.E., Signing Engineer with
ODOT’s Office of Traffic Operations, at (614) 752-0438. Assistance may also be available
from Traffic Engineering staff at the ODOT District Office in your area, or from your County
Engineer’s Office.
“How can I access the OMUTCD?” The 2012 Edition of the OMUTCD is available online for viewing or downloading (free of charge), at: www.dot.state.oh.us/omutcd. Printed copies are also available. The Manual is provided free to government agencies, local jurisdictions, schools and public libraries; to others there will be a charge. The cost is $34.50 plus shipping and tax. Requests should be directed to ODOT’s Office of Contracts at 1-800-459-3778 or 614-466-3778.
DISCLAIMER: This RON Technical Update is provided for purposes of general information only. This
is not a primary technical or legal authority, and should not be relied upon as such. Interested
persons should refer to the source publications referenced herein. Please note also that information
contained in this document could become outdated or obsolete over time.