Traffic Control Devices
these are the equipment and installations over and on the road which individually and collectively perform the following tasks.
(i) Warn the road user
(ii) Inform the road user
(iii) Guide the road user
(iv) Modify road user behaviour
(v) Protect the road user and the vehicle
(vi) Ensure safe passage to the road user
(vii) Provide a safe working area.
the primary traffic control devices used in working zones are signs, delineators, pylons, pavement marking, barricades, cones and flashing lights.
The following general rules should apply to all these devices.
(A) Comprehension:
it should be capable of being easily understood, must convey one and only one meaning, good and clean condition of the device aids comprehension.
(B) Visibility and stability :
it should be clearly visible both day and night properly aligned and legible at all times. these should not act as a rigid obstacles in the event of a collision.
(C) Maintenance:
It should be serviced and maintenance correctly.
Spare devices must be available during the entire period of construction.
(a) Clear visibility
(b) Signs should be so placed that driver should have time for responses (c) it should be placed on left hand side of the road. Where special emphasis is required, duplicate signs should be installed at right side of roadway also.
In hill roads, these are generally placed on the valley side of road unless road conditions warrant these to be placed on the hill side; and
(d) The signs should be covered or removed when they are not required.
Positioning of signs
the outermost edge of sign adjoining to shall not be less than 600 mm apart from the edge of the kerb on kerbed roads.
On unkerbed roads, the extreme edge of the sign adjacent to the road shall be at a distance of two to three metre away from the edge of the carriageway depending on local situation but in no case, shall any part of sign come in the way of traffic.
Regulatory Sign
It imposes legal restrictions on all traffic.
It is essential that they are used only after consulting local police and traffic authorities.
The most probably type of regulatory signs to be used in traffic control zones are Stop, Give Way, Do Not Enter, One Way, Straight Prohibited, Vehicles Prohibited in Both Directions, Left Turn Prohibited, Right Turn Prohibited, 'U' Turn Prohibited, Overtaking Prohibited, No Parking, No Stopping and No Standing, Keep Left, Compulsory Left Turn, Compulsory Right Turn, Compulsory Straight or Left Turn, Priority to vehicles in other direction, Priority to vehicles in this direction, Weight Limit, Axle Limit, Height Limit, Length Limit, Restriction Ends, Speed Limit Various other signs that are needed to regulate traffic may be required, which have not been standardized.
They should conform to the general requirements of shape and colour and
Warning Signs
These are utilized in the traffic control zone to warn the drivers of specific hazards that may be encountered. Drivers should be alerted to potential hazards in sufficient time to adjust their movement and speed.
The most common type of warning signs for the use in the traffic control zone are : Men At Work, Road Narrows (Single File Traffic), Right Lane Diverted, Left Lane Diverted, Right Lane Closed, Left Lane Closed, Median Closed, Diversion to other Carriageway, Traffic Signal Ahead Two Way Traffic, Rough Road, Slippery Road, Loose Chippings, Divided Road and Divided Road Ends.
