3.1. Traffic Control Devices

Traffic control devices are used in conjunction with worksite signs in order to function as the following:

  • to define the traffic path,
  • to inhibit access into the work area or
  • to act as a barrier to protect workers.

Positioning of Devices

  • Properly displayed and securely mounted
  • Within the line of sight of the intended road user
  • Not be obscured from view either by vegetation or parked cars
  • Not a possible hazard to workers, pedestrians or vehicles
  • Not to force traffic into an undesirable path
  • Signs and devices should generally be placed 1 meter clear of the traveled path.
  • Signs that are erected on posts (measured from the underside of the sign)
  • Rural 1.5meters minimum above the level of the roadway
  • Urban 2.2meters above the level of curb or footpath

3.1.1.  Description and Use of Signs and Devices

3.1.2.  Signs and Devices for Worksite Approaches

  • Used to give advance warning of all long term work sites roadworks and bridgeworks.
  • The sign is generally not necessary at short term works, but may be desirable for short term works in high speed roads or bridges where additional advance warning is considered necessary.
  • Used x km in advance of roadworks/bridgeworks where additional warning is required.
  • The Workmen Ahead symbolic sign is used to give warning of workers undertaking short-term or long-term works.
  • This sign shall only be displayed when workers are working and are visible to traffic.
  • The sign should always be used when a Traffic Controller is controlling traffic.
  • Used at work sites where machinery is working on the roadway with no form of traffic control.
  • Used where a grader is engaged in pavement, shoulder or roadside maintenance.
  • Used in conjunction with either the WORKMEN AHEAD (symbolic) sign, ROAD MACHINERY AHEAD or GRADER AHEAD signs for a frequently changing work area.
  • Used to supplement other advance signs where there are a series of two or more work areas within the one worksite.
  • Used in advance of an intersection to warn road users of roadwork activities on the side road.

3.1.3.  Signs and Devices for Worksite Departures

Used at the departure end of the work site.

  • The sign is not necessary on mobile works, short term works or where an END DETOUR sign is used.

3.1.4.  Signs and Devices for Regulatory Control Traffic

Signs or Flags are used by a Traffic Controller to control traffic:

  • at any temporary obstruction or hazard (eg. blasting or machinery crossing the road)
  • where one lane of a two-way road or bridge is closed.
  • Flags are only suitable in low traffic volume situations, generally in rural areas.
  • Prepare to Stop is used to give advance warning where traffic may be required to stop at the direction of a Traffic Controller (Flagman) or at portable temporary traffic signals.
  • Speed Restriction sign used to create a temporary road works speed limit either for worker safety or traffic safety.
  • Used with the speed restriction sign at the start of a roadwork speed limit to indicate that the speed zone is associated with road works.  Alternatively, the speed limit sign can be installed with the advance warning ROADWORK AHEAD sign.
  • May be used at the end of a road works regulatory speed restriction where the road does not have a signed speed limit.

3.1.5.  Devices for Delineating and Indicating the Traveled Path

Temporary Hazard Markers. are used as part of a taper or to show a lateral change of direction of the traveled path. May also be used to warn of an adjacent hazard or closed length of road or shoulder.

The smaller marker may be used for a lateral change of direction in confined areas where there is insufficient space to use the wider marker.  It may also be used at the start of a taper.

Traffic Cones or Temporary Bollards are used to indicate the path that traffic should follow past or around the worksite – delineation of tapers, merges, lane separation etc. spacing varies according to usage (refer Road Work Safety Manual).

3.1.6.  Signs and Devices – Traffic Cone

  • shall be fluorescent red or orange plastic
  • resilient to impact and will not damage vehicles when hit at low speed.
  • height: varies from 450mm up to 750 mm for use on expressways or in very high speed situations.
  • shall be designed to be stable in wind and the air turbulence from passing traffic.
  • at night time operation the cones must be fitted with reflective tape with a minimum bandwidth of 150mm.
  • Traffic cones must be checked on a regular basis as they can be easily knocked out of position by passing vehicles.

Recommended Spacing of Bollards or Cones

3.1.7.  Signs and Devices – Temporary Bollard

Temporary Bollards are used to define the path that traffic should follow or around the worksite. (e. g. when delineating tapers, merges, lane separation, or longitudinal separation and delineation between traffic and the outer edge of a widening excavation or worksite.)

  • useful in place of traffic cones if greater stability is required
  • shall be fluorescent red or orange plastic that is resilient to impact and will not damage vehicles when hit at low speed. 
  • Height: up to 1 meter.  
  • For night time operation the bollards must be fitted with reflective tape with a minimum bandwidth of 250mm. 

Bollards must be checked on a regular basis as they can be easily knocked out of position by passing vehicles.  Bollards may be fixed to the roadway to keep them in position. Alternatively they may be stabilized with a bag of sand or gravel on the base.

3.1.8.  Signs and Devices – Barrier Boards

A barrier board mounted on a trestle is a useful device for inhibiting access to a worksite.

  • Board dimensions: (4m x 0.15m x 0.20m) with diagonal black and reflective yellow stripes preferably terminating in yellow at each end.
  • Mounting Height: approximately 1m using trestles (should be erected perpendicular to the direction of traffic flow)

Note:

Barrier boards can be a spearing hazard if the end is struck by an errant vehicle, so they shall not be used for delineation purposes or installed parallel to vehicular traffic unless there is an offset of at least 4 meters from the travelled path.

3.1.9.  Signs and Devices – Concrete/Water-filled plastic Barriers

Safety Barriers                                     

  • used for the separation of traffic and the protection of workers in high speed areas or in vulnerable situations where lateral clearance between workers and moving traffic would be insufficient for adequate safety.
  • may be used for protection at a severe hazard such as a deep excavation or bridge pier.

Safety barriers physically separating traffic from the work area shall be designed to restrict penetration by an out of control vehicle, and as far as practicable, to redirect errant vehicles away from the works area and back onto the traffic path.

Types of Safety Barriers

  • Concrete Barriers
  • Water-filled Plastic Barriers

Note:

  • The end of a safety barrier shall be tapered away to provide an offset from approaching traffic. 

Where an approach taper cannot be provided, a temporary crash cushion should be considered as an energy absorbing device to reduce the severity of a collision by an out of control vehicle.

Temporary Crash Cushion

  • should be provided at hazardous fixed objects such as the end of a safety barrier or an unprotected bridge pier. 
  • acts as an energy absorbing device to reduce the severity of a collision by an out of control vehicle.

3.1.10.  Signs and Devices – Containment fences

May be used to provide separation between traffic and workers in situations where physical protection using a safety barrier is not warranted. May also be used to separate pedestrians from the work area.

  1. Lightweight Plastic units
  2. Tapes
  3. Mesh Fencing
  1. Lightweight Plastic units
  • may be used to provide delineation or a physical separation adjacent to the work area.
  • should be connected together to provide a continuous barrier and to avoid the possibility of units being knocked out of position.                                           
  • not suitable as a safety barrier for high speed areas or in vulnerable situations as they do not meet safety barrier performance criteria. 
  • should not be used for the purpose of protecting workers where traffic speed is likely to exceed 20kph

Generally, lightweight plastic units are not suitable as a safety barrier for high speed areas or in vulnerable situations as they do not meet safety barrier performance criteria.  Therefore, they should not be used for the purpose of protecting workers where traffic speed is likely to exceed 20kph.  However, plastic units that are reinforced and secured together with cabling may be suitable as a safety barrier.  

  • Tapes
  • May be  used to contain workers within the work area.
  • The tape shall be tied or supported approximately one (1) meter high. 
  • The tape shall be 100 mm wide with alternating black and yellow stripes.
  • Mesh Fencing
  • may be used adjacent to the works area to contain workers within the work area or to separate passing pedestrians from the work area. 
  • not suitable for control of vehicles or protection of workers from vehicles. 
  • generally red or orange plastic mesh approximately 1 meter high.  It shall be securely tied or supported in place.

3.1.11.          Signs and Devices – Vehicle Mounted Equipment

  1. WORKERS sign
  • This double-sided folding warning device is mounted on the top of a works vehicle.
  • It would be folded into the upright position and made visible to motorists when moving slowly or when stopped to carry out works.
  • This device would be suitable for use on low volume roads.

2. Rotating Lights

  • Yellow rotating lights are generally mounted on the top of the works or inspection vehicle and activated when moving slowly or when stopped to carry out works. 
  • A single portable rotating light may be used for emergency or mobile inspections on a vehicle not usually used for roadwork purposes. 
  • Two flashing lamps mounted on either side on the top of a mobile maintenance vehicle would generally be a suitable warning device for use on low speed roads.

3. Flashing Arrow Board

  • generally mounted on the top of the works vehicle and activated when moving slowly or when stopped to carry out works.   
  • used as a warning device by flashing the bar only.  Alternatively the four corner lights at the extremities of the barbs may be flashed as diagonal pairs. 
  • the flashing arrow board is the preferred warning device for works on high speed roads.

3.1.12.          Signs and Devices – Variable Messages Signs (VMS)

  • Used to provide long range warning to road users of roadworks, road conditions or traffic hazards on the road ahead. 
  • Normal use would be on high speed or high volume roads where conventional signage may be ineffective, or in an emergency where normal signs cannot be arranged. 
  • Messages should be kept to a maximum of three lines per frame and the message text centred. 
  • Messages shall be concise and unambiguous for driver comprehension.   
  • Messages should comprise a maximum of two frames.
  • The message update shall be scrolled. ‘Flashing’ or ‘blinking’ of messages is undesirable.

Location:

  1. In urban areas – behind the curb if visible to oncoming traffic.  Otherwise on the roadway as near as practicable to the curb with appropriate taper and signs to guide motorists past the sign. 
  2. On expressways – beyond the shoulder if possible, otherwise on the shoulder. 

3.1.13.          Signs and Devices – Portable Traffic Signal

  • may be used instead of Traffic Controllers to control traffic at a worksite.
  • traffic signals would generally be considered for use at sites with high traffic volumes or where reliable continuous traffic control may be needed over an extended period.
  • they would generally be used at worksites where the width of a bridge or roadway available to traffic has been narrowed to a single lane that must be used alternately by traffic from opposite directions. 
  • portable signals may also be used where construction traffic or machinery crosses a roadway between different sections of a worksite.
  • a battery or generator would usually power portable traffic signals.
  • red, yellow and green traffic lights provide regulatory control of traffic in a similar manner as permanent traffic signal installations.  The signals would be connected and operated by cable or by radio.
  1. The STOP HERE ON RED SIGNAL (R6-6) sign shall be used in association with portable signals to indicate where traffic must stop.  This sign detail is included in the Philippines Road Signs and Pavement Markings Manual.
  • The Signals Ahead (W3-3) sign shall also be used to give advance warning of the traffic signals.  This sign detail is included in the Philippines Road Signs and Pavement Markings Manual.