§ 8.5.7. Temporary Traffic Control Zone Devices

The following section describes the design and applications of traffic control devices used in temporary traffic control zones. A traffic control device is a sign, signal, marking or other device placed on or adjacent to a street or highway (by authority of a public body or official having jurisdiction) to regulate, warn, or guide traffic.

A.

Signs

Signs used in temporary traffic control zones fall into three (3) categories, warning, regulatory, and guide.

1.

Warning Signs

This category of signs is used when it is necessary to warn traffic of exiting potentially hazardous conditions on or adjacent to the roadway or sidewalk. Warnings signs require caution on the part of the vehicle operator or the pedestrian and may require a reduction of speed or maneuver in the interest of safety.

Warning signs in temporary traffic control zones have black legends with an orange background. Yellow warning signs within the temporary traffic control zone which are still applicable may remain in place. Warning signs shall be retroreflective or illuminated for nighttime visibility. Roadway lighting does not meet the requirement for sign illumination.

2.

Regulatory Signs

Regulatory Signs impose legal obligations and restrictions on all traffic. They may only be used under the authority of the agency responsible for traffic control. Therefore, no regulatory sign shall be used without the authorization of the Transportation, Planning and Sustainability Department.

3.

Guide Signs

Guide signs show route designations, destinations, directions, distances, services, points of interest, and other geographical, recreational, or cultural information. The following guide signs used as needed at temporary traffic control zones:

a.

Standard route markings, where temporary route changes are necessary.

b.

Directional signs such as motorist service signing, recreational and cultural interest area signs, driveway entrance signs, civil defense signing, and street name signs. When used with detour routing, these signs may have a black legend on an orange background.

c.

Special information signs relating to work being done. These signs shall have a black legend on an orange background.

Typical signs used in temporary traffic control zones are shown in Figure 8-10.

4.

Sign Mounting and Placement Principles

As a general rule, signs should be located on the right-hand side of the roadway. When special emphasis is needed or on one-way roadways, signs shall be placed on both the left and right sides of the roadway, where space is available. Signs shall be placed in positions where they will convey their messages most effectively. The following statements provide good placement principles.

•  Visibility to oncoming motorist and pedestrians is essential.

•  Signs should never be positioned where essential sight lines from intersecting driveways or streets are blocked.

Figure 8-9 Use of Hand Signaling Devices by Flagger

•  The first warning sign shall never be placed in the street itself.

•  Signs used only during the day shall be covered or removed at night.

•  Signs shall be removed or changed immediately if condition change.

Typical construction warning sign size and spacing requirements are shown in Table 8-4. Portable sign supports shall only be used for Short-term stationary or Short Duration activities, as defined in Section 8.5.9. Signs mounted on portable sign supports shall be mounted a minimum of 300 millimeters (1 foot) above ground level. Temporary and fixed sign supports shall be used for all Long-term Stationary or Intermediate-term Stationary activities. Signs mounted on temporary and fixed sign supports shall be mounted a minimum of 2.1 meters (7 feet) above ground level. Approved typical sign supports are shown on Standard Detail Sheet 804-5. Only warning signs found in the Texas Manual on Uniform Traffic Control Devices (TMUTCD) or this manual may be used at temporary traffic control zones. Any variation must be approved by the Transportation, Planning and Sustainability Department. Advisory speed signs may only be used if authorized by the Transportation, Planning and Sustainability Department.

5.

Arrow Displays

Arrow Displays are intended to provide additional warning and directional information to assist in merging and controlling traffic through and around temporary traffic control zones. Arrow displays will not solve difficult traffic problems by themselves, but they can be very effective when properly used to reinforce signs, barricades, cones and other traffic control devices. . For this reason arrow displays are required for all lane closures. Necessary signs, barricades or other traffic control devices shall be used in conjunction with the arrow displays.

B.

Channelizing Devices

Channelizing devices are used to warn and alert drivers and pedestrians of conditions created by work activities in or near the travel way, to protect workers in the temporary traffic zone, and to guide and direct drivers and pedestrians safely through or around the temporary traffic control zone. Channelizing devices should be constructed and ballasted to perform in a predictable manner when inadvertently struck by a vehicle. If struck, they should yield or break away, and fragments or other debris from the device should not penetrate the passenger compartment of the vehicle or be a potential hazard to workers or pedestrians in the immediate area.

Figure 8-10 Typical Signs Used in Temporary Traffic Control Zone

Table 8-4 Typical Construction Warning Sign Size and Spacing

Roadway Classification	Posted Speed	†Sign Spacing	Long-term Stationary Or Intermediate-term Stationary Approach Warning Signs CW20 Series And CW22-1 Sign		Short-term Stationary Or Short Duration Approach Warning Signs CW21 Series		Other Warning Signs
			Standard	Minimum 4	Standard	Minimum 4	Standard
	MPH	Approx. m (feet)	mm (inches)	mm (inches)	Mm (inches)	Mm (inches)	mm (inches)
Conven.	30	40 (120)	1219×1219 (48x48)	914×914 (36x36)	914×914 (36x36)	Use Standard	914×914 (36×36)
	35	50 (160)
	40	75 (240)
	45	100 (320)		Use Standard Size
	50	120 (400)
	55	150 2 (500)
	60	180 2 (600)			1219×1219 (48x48)		1219×1219 (48x48)
	65	210 2 (700)
	70	240 2 (800)
Exp. Or Fwy	*	**			**	**	**

 

*  For typical sign spacings on expressways and freeways, see the typical applications diagrams.

†  Minimum distance from work to 1st Advance Warning sign and/or distance between each additional sign.

**  Smaller sign sizes may be used where sign designs have not been included in the "Standard Highway Sign Designs Manual."

General Notes:

1.

Special or larger size signs may be used as may be necessary.

2.

Distance between signs should be increased as required to have 450 meters (1500′) advanced warning.

3.

Distance between signs should be increased as required to have 0.8 km (½ mile) or more advance warning.

4.

For use only on secondary roads or city streets where speeds are low.

5.

Only diamond shaped warning sign sizes are indicated.*

_____

The devices include traffic cones/tubular marker, vertical panels, plastic drums, barricades and barriers.

1.

Traffic Cones/Tubular Markers

The primary purpose of this group of devices is to channelize traffic and to delineate short duration activities. Cones shall be predominantly orange, fluorescent red-orange, or fluorescent yellow-orange, and shall be made of a material that can be struck without damaging vehicles on impact. Cones used for delineating traffic shall be a minimum of 700 millimeters (28 inches) in height. Cones used for marking of wet paint on striping operations may be 450 millimeters (18 inches) in height. Tubular markers shall be predominantly orange, minimum 51 millimeters (2 inches) wide when facing traffic, and made of material that can be struck without damaging vehicles. Tubular markers shall be a minimum of 700 millimeters (28 inches) height.

For nighttime use, cones and tubular markers shall be retroreflective or equipped with lighting devices for maximum visibility. Retroreflection of cones shall be provided by a white band 150 millimeters (6 inches) wide, no more than 75 to 100 millimeters (3 to 4 inches) from the top of the cone, and an additional 100 millimeter (4 inch) wide white band a minimum of 50 millimeters (2 inches) below the 150 millimeter (6 inch) band. Retroreflection of tubular markers shall be provided by two 75 millimeter (3 inch) wide white bands placed a maximum of 50 millimeters (2 inches) from the top, with a maximum of 150 millimeters (6 inches) between bands. If cones are used at night, the temporary traffic control zone must be continuously manned in order to ensure that cones or tubular markers are not displaced by wind or moving traffic. See Standard Detail Sheet 804-5 for additional information.

2.

Vertical Panels

Vertical panels may be used to channel traffic, divide opposing lanes of traffic, divide traffic lanes or in place of barricades where space is limited. Vertical Panels shall be made of a material that can be struck without damaging vehicles on impact.

Vertical panels shall be a minimum of 200 to 300 millimeters (8 to 12 inches) wide and at least 600 millimeters (24 inches) high. They shall have orange (fluorescent red-orange or fluorescent yellow-orange) and white stripes, and be retroreflective. Panel stripe widths shall be 150 millimeters (6 inches), except where panel heights are less than 900 millimeters (36 inches), when 100 millimeter (4 inch) stripes may be used. If used for two-way traffic, back-to-back panels shall be used.

Markings for vertical panels shall be alternating orange and white retroreflectorized stripes (sloping downward at an angle of 45 degrees in the direction traffic is to pass). Vertical panels used on expressways, freeways, and other high-speed roadways shall have a minimum of 174,193 square millimeters (270 square inches) of retroreflective area facing traffic. See Standard Detail Sheet 804-5 for additional information.

3.

Drums

Drums are most commonly used to channelize or delineate traffic flow but may also be used singly or in groups to mark specific locations. Drums are highly visible and have good target value, given the appearance of being formidable obstacles and, therefore, command the respect of drivers.

Drums used for traffic warning or channelization shall be constructed of lightweight, flexible, and deformable materials and be a minimum of 900 millimeters (36 inches) in height; and have at least an 450 millimeters (18 inch) minimum width, regardless of orientation. Steel drums shall not be used. The markings on drums shall be horizontal, circumferential, alternating orange and white retroreflective stripes 100 200 millimeters (4 to 6 inches) wide. Each drum shall have a minimum of two orange and two white stripes. Any non-retroreflective spaces between the horizontal orange and white stripes, shall not exceed 50 millimeters (2 inches) wide. Drums shall have closed tops that will not allow collection of roadwork or other debris.

4.

Barricades

A barricade is a portable or fixed device having from one (1) to three (3) rails with appropriate markings used to control traffic by closing, restricting or delineating all or a portion of the right of way.

Barricades are located adjacent to traffic and are therefore subject to impact by errant vehicles. Because of their vulnerable position and the hazard they could create, they should be constructed of lightweight materials and have no rigid stay bracing for A-frame designs.

There are three types of barricades: Type I, Type II and Type III. Figure 8-11 illustrates the proper stripping configuration for various barricade applications.

Type I Barricades

Type I Barricades are intended for the use in situations where traffic will be maintained through the temporary traffic control zone. They may be used singly or in groups to mark specific conditions or may be used in a series for channelizing traffic.

Type II Barricades

Type II Barricades may be used much like the Type I. Type II Barricades have more reflective area and they are intended to be used on higher speed roadways or where high visibility is needed. Where barricades may be susceptible to overturning in the wind, sandbags may be placed on the lower parts of the frame supports to provide ballast but shall not be placed on the top of any striped rails.

Type III Barricades

Type III Barricades are intended to be used in temporary traffic control zones for which sections of the roadway will be closed to traffic. At least one (1) Type III barricade shall be erected at the points of closure. Type III barricades used at a road closure may extend completely across a roadway or from curb to curb. Where provision is made for access of authorized equipment and vehicles, the responsibility for the Type III barricades should be assigned to a person to ensure proper closure at the end of each work day.

When a roadway is legally closed but access must still be allowed for local traffic, the Type III barricade should not be extended completely across a roadway. A sign with the appropriate legend concerning permissible use by local traffic shall be mounted.

5.

Safety Fences

Safety fences are used to separate pedestrians and motorist from specific conditions in the right-of-way. They must be a minimum of 1.2 meters (4 feet) tall and may be made out of wood, orange polyurethane plastic or chain link material. If the fence is to be placed within the roadway, the fence shall be retroreflective and/or have stripped barricade panels and warning lights. Lights, if required, shall be placed at least every 9 meters (30 feet) along the fence. In all cases, fences must be set back a minimum of 300 millimeters (1 foot) from the existing lane as marked on the street. Standard Detail Sheet 804-4 for additional information.

6.

Pedestrian Walkways

Pedestrian Walkways separate pedestrians from both the work site and adjacent traffic. A canopied walkway will be required when the distance to the construction activity is less than the height of the work activity. Pedestrian Walkways should be sturdily constructed and adequately lighted for nighttime. Figure 8-12 illustrates a typical canopied pedestrian walkway and provides the specifications for their use.

Sight distance must be maintained at corners and openings. Ends of pedestrian walkways placed in traffic lanes, facing oncoming traffic must have stripped barricade panels. In all cases, walkways must be set back a minimum of 300 millimeters (1 foot) from the existing lane as marked on the street. In places where pedestrians are judged especially vulnerable to impact by errant vehicles, all foot traffic should be separated and protected by longitudinal barrier systems.

Figure 8-11 Barricade Specifications

7.

Portable Barriers

When work activities necessitate excavations to remain open within the roadway, portable barriers shall be used to protect vehicles from the excavation. Portable barriers are designed to prevent vehicles from penetrating work areas behind the barrier while minimizing vehicle occupant injuries. They may also be used to separate two-way traffic. These devices are usually concrete traffic barriers (CTB), Low Profile Barriers (LPB) or Water Filled Traffic Barriers (WFTB)

When serving the additional function of channelizing traffic, the barrier taper shall meet the standard channelizing taper lengths. The Channlizing barrier shall be supplemented by standard delineators, channelizing devices, or pavement markings. Channelizing barriers should not be used for a merging taper except in low-speed urban areas.

8.

Warning Lights

The lightweight and portability of warning lights are advantages that make these devices useful as supplements to the retroreflectorization on hazard warning devices. The flashing lights are effective in attracting a driver's attention and, therefore, provide an excellent means of identifying the hazard.

As used herein, warning lights are portable, lens-directed, enclosed lights. The color of the light emitted shall be yellow. They may be used in either a steady-burn or flashing mode.

Warning lights shall have a minimum mounting height of 750 millimeters (30 inches) to the bottom of the lens. Type A low intensity flashing warning lights and Type C steady-burn warning lights shall be maintained so as to be visible on a clear night from a distance of 900 meters (3,000 feet).

Type A low-intensity flashing warning lights are most commonly mounted on barricades, drums, vertical panels, or advance warning signs, and are intended to warn drivers that they are approaching or are in a potentially hazardous area. All warning signs shall have a Type A warning light.

Type C steady-burn lights are intended to be used to delineate the edge of the traveled way on detour curves, on lane changes, on lane closures, and on other similar conditions. All devices used in tapers shall have Type C warning lights. All other channelizing devices may use either Type C warning lights or an approved large reflectors/ object markers.

C.

Temporary Pavement Markings

Adequate pavement markings shall be maintained along all streets in temporary traffic control zones. The work should be planned and staged to provide the best possible conditions for the placement and removal of the pavement markings. It is intended, to the extent possible, that motorists be provided markings within a work area comparable to or better than the markings on each approach to the temporary traffic control zone. The following guidelines apply to the use of temporary pavement markings.

Figure 8-12 Pedestrian Canopy Walk Way

1.

Inappropriate pavement markings should be removed and the new markings placed before opening the affected lane or lanes to traffic.

2.

Conflicting pavement markings shall be obliterated to prevent confusion to drivers. Proper pavement marking obliteration leaves a minimum of pavement scars and completely removes old marking materials. Obliterated markings shall be unidentifiable as pavement markings under day or night, wet or dry conditions. Overlaying existing stripes with black paint or asphalt does not meet the requirements of covering, removal, or obliteration. Sand blasting is the preferred method of obliteration. However, light grinding maybe used on thermoplastic and or roadways that will be resurfaced prior to final striping.

3.

When a temporary roadway is constructed to bypass a closed portion of the street, appropriate reflectorized pavement markings shall be placed on the approach to, and throughout the length of hard-surfaced temporary roadways.

4.

Temporary pavement markings shall be maintained in long-term stationary work areas and shall match and meet the markings in place at both ends of the work area.

5.

Temporary pavement markings should be provided in intermediate-term stationary work areas, to the extent practicable.

6.

Short-Term pavement markings should normally be used only on newly resurfaced roadways. However, they maybe used in other situation with prior approval.

7.

Pavement marking installations within temporary traffic control zones shall be accomplished only on weekends unless prior approval has been obtained from the Transportation Division of the Transportation, Planning and Sustainability Department.

See Standard Detail Sheet 804S-3 for additional information.