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,

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.

Use of Horizontal Alignment Warning Signs

http://www.dot.state.oh.us/LTAP

http://www.dot.state.oh.us/Divisions/Engineering/Roadway/DesignStandards/traffic/OhioMUTCD/Pages/OMUTCD2012_current_default.aspx


Horizontal Alignment Signs (W1-1 through W1-5, W1-11, W1-15) (See Section 2C.07)

Standard:

If Table 2C-5 indicates that a horizontal alignment sign (see Figure 2C-1) is required,

recommended, or allowed, the sign installed in advance of the curve shall be a Curve

(W1-2) sign unless a different sign is recommended or allowed by the provisions of this

Section.

A Turn (W1-1) sign shall be used instead of a Curve sign in advance of curves that have

advisory speeds of 30 mph or less (see Figure 2C-2). [shown on page 4]

Guidance:

Where there are two changes in roadway alignment in opposite directions that are separated by

a tangent distance of less than 600 feet, the Reverse Turn (W1-3) sign should be used instead of



multiple Turn (W1-1) signs and the Reverse Curve (W1-4) sign should be used instead of

multiple Curve (W1-2) signs.

Option:

A Winding Road (W1-5) sign may be used instead of multiple Turn (W1-1) or Curve (W1-2)

signs where there are three or more changes in roadway alignment each separated by a tangent

distance of less than 600 feet.

A NEXT XX MILES (W7-3aP) supplemental distance plaque (see Section 2C.55) may be

installed below the Winding Road sign where continuous roadway curves exist for a specific

distance.

If the curve has a change in horizontal alignment of 135 degrees or more, the Hairpin Curve

(W1-11) sign may be used instead of a Curve or Turn sign.

If the curve has a change of direction of approximately 270 degrees, such as on a cloverleaf

interchange ramp, the 270-degree Loop (W1-15) sign may be used instead of a Curve or Turn

sign.

Guidance:

When the Hairpin Curve sign or the 270-degree Loop sign is installed, either a One-Direction

Large Arrow (W1-6) sign or Chevron Alignment (W1-8) signs should be installed on the outside

of the turn or curve.



[refer to OMUTCD Chapter 2C for Tables 2C-4, 2C-5, 2C-6, and additional information]



Advisory Speed Plaque (W13-1P) (See Section 2C.08) Option:

The Advisory Speed (W13-1P) plaque (see Figure 2C-1) may be used to supplement any

warning sign to indicate the advisory speed for a condition.

Standard:

The use of the Advisory Speed plaque for horizontal curves shall be in accordance with the

information shown in Table 2C-5. The Advisory Speed plaque shall also be used where an

engineering study indicates a need to advise road users of the advisory speed for other

roadway conditions.

If used, the Advisory Speed plaque shall carry the message XX MPH. The speed displayed

shall be a multiple of 5 mph.

Except in emergencies or when the condition is temporary, an Advisory Speed plaque shall

not be installed until the advisory speed has been determined by an engineering study.

The Advisory Speed plaque shall only be used to supplement a warning sign and shall not

be installed as a separate sign installation.

The advisory speed shall be determined by an engineering study that follows established

engineering practices.

The speed shown on the advisory speed plaque shall be equal to or less than the posted or

statutory speed limit. Where the advisory speed is determined to be higher than the posted

or statutory speed limit, the advisory speed plaque shall not be used.

“How is the advisory speed determined?”

Please refer to the complete text of Section 2C.08 for discussion of established engineering

practices for determining the recommended advisory speed for a horizontal curve. Townships

and other local agencies may contact their County Engineer’s office to request assistance with

determining advisory speeds. The ODOT District offices also typically have traffic engineering

personnel who can provide technical assistance.

One common engineering practice for determining the recommended advisory speed for a

horizontal curve is the use of a ball-bank indicator device. Many of the County Engineer offices

are familiar with the use of this device, and the ODOT District offices received digital ball-bank

indicators in 2010. Also, ODOT’s Local Technical Assistance Program (LTAP) office has

established an equipment loan program that includes digital ball-bank indicators. Please refer to

the LTAP website (http://www.dot.state.oh.us/LTAP) for additional information.

Chevron Alignment Sign (W1-8)

Please refer to OMUTCD Section 2C.09 for standards and guidance regarding proper use of

Chevron Alignment signs.




Combination Horizontal Alignment/Advisory Speed Signs (W1-1a, W1-2a) (See Section 2C.10) Option:

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

practices (see Section 2C.08).



“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.


http://www.dot.state.oh.us/omutcd


Notes:


Documents

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,