Road markings are used as a means of controlling and guiding traffic. They are highly important on urban roads and intersections as they promote road safety and bring out smooth and harmonious flow of traffic along guided paths of travel. They also supplement the messages conveyed by road signals and signs. In some cases, they are used alone to convey certain regulation, information or warning that cannot otherwise be effectively made known to the road users. Road surface markings are the devices on a road surface in order to convey official information. Road surface markings are used on paved roadways to provide guidance and information to drivers and pedestrians. Uniformity and standardization of the markings is an important factor in minimizing confusion and uncertainty about their meaning. These do help in reducing the accidents and manpower requirements for regulating traffic.
The main functions of the road markings are to guide the safe and smooth flow of traffic in the following ways:
They should convey the required information to the driver without distracting his attention from the carriageway, for which the following rudimentary requirements should be met:
Road markings are basically of two types: Carriageway markings and Object markings3.1 Carriageway markings As the name implies, these are the markings applied to the carriageway. Carriageway markings are of the following categories:
Object markings are of the following categories:
Carriageway markings are again classified in two types: Longitudinal Markings & Transverse Markings. Guidelines for Road Markings QTCM
Longitudinal markings are placed along the direction of traffic on the roadway surface, for the purpose of indicating to the driver, his proper position on the roadway. Some of the guiding principles in longitudinal markings are given below.
Different types of longitudinal markings are centre line, traffic lanes, no passing zone, warning lines, border or edge lines, bus lane markings and cycle lane markings. 4.1.1 Centre Line Centre line separates the opposing streams of traffic and facilitates their movements. Usually no centre line is provided for roads having width less than 5 m and for roads having more than four lanes with the central verge. The centre line may be marked with single broken line, single solid line, double broken line, or double solid line depending upon the road and traffic requirements. A centre line marking is provided to demarcate the centre of a carriageway and to separate traffic in opposite directions. 4.1.2. Centre line marking for two lane road On roads with less than four lanes or on those roads having four lanes and on which parking is permitted thus reducing the operational width, the centre lines shall consist of single broken line 150mm wide of 3 m long segments with 4.5 m gaps. On curves and approaches to intersections, the gap shall be 3 meters as shown in Fig.1. The colour of the centre line shall be yellow. 4.1.3. Lane Line Markings M100 and M101 are used to separate traffic from adjacent traffic to ensure roadway space is clearly marked to maximize capacity. Marking M100 is used on roadways where the posted speed is 80 kilometers per hour (kph) or less and minor arterial and local routes. Marking M101 is for use on roadways where the posted speed is over 80 kph.
4.1.4. No passing / No overtaking Line Markings M116 and M117 are used to prohibit overtaking where visibility is restricted on two-way single roadways where the forward visibility distance falls below the lower limits specified (warning lines). The continuous line indicates to drivers that they may not leave the lane in which they are travelling. Furthermore, the markings prohibit vehicles from stopping or parking at any point between the ends of the marking. Any vehicle that does stop may result in other vehicles having to cross over the marking,
4.1.5. Pavement Edge Lines Pavement edge lines are used to indicate the edges of carriageways which have no curbs. They serve as a visual guidance for the drivers, indicating to them the limits up to which the driver can safely venture. They especially are useful during adverse weather and poor visibility where the paved shoulder is of a lesser structural strength than the main pavement, the edge lines are used to promote travel on the main pavement itself. Edge lines are in the form of a single continuous line placed about 150 mm from the edge. The width of the line is 150 mm on multi lane roads without median the width may be 200 mm as shown in Fig. 5. Where flush kerbs are provided, the edge lines should be superimposed. The marking should preferably be reflectorized or incorporate crusted calcined flint or other such material.
Bus lanes and bus facilities are those that are reserved for the use of buses and can be in operation at all times or part-time; for instance, the bus lane may only need to be in operation during the peak hours to facilitate movements and encourage sustainable travel. The times of operation for a bus lane will be displayed on accompanying upright signs. With-Flow Bus Lanes With-flow bus lanes are lanes buses travel in the same direction as traffic in the adjacent lane. Where roadways are wide enough, the bus lane should be 4.25 m wide, with a minimum preferred width of 4m.
4.1.7. Bicycle lane Marking Bicycle lane markings should be provided when a portion of the carriageway, being used by motorized vehicles, is earmarked for exclusive use of cyclists. Markings M320 and M321 separation lines (directional separation) for use on shared paths to separate opposing flows of travel where required. Marking M320 is an unbroken 80 mm wide white marking, and marking M321 is a broken 80 mm wide marking consisting of a 1 m line and 5 m gap.
Marking M322 – Separation line (user separation) for use on separated paths to delineate pedestrian and bicyclist paths. The marking is an unbroken white line 100 mm wide.
Marking M324 is used to delineate the bike path and must be white with a size of 1,100 mm by 1,780 mm.
Marking M325 is the pedestrian symbol used to denote areas of the sidewalk for pedestrian travel. The marking is white and 580 mm by 1,200 mm.4.2. Transverse marking Transverse markings are marked across the direction of traffic and width of markings should be more than the longitudinal markings. They are marked at intersections areas and approaches to intersections. The site conditions play a very important role. The type of road marking for a particular intersection depends on several variables such as speed characteristics of traffic, availability of space etc. Stop line markings, give way lines, markings for pedestrian crossing, cyclist crossing, markings on speed change lane, direction arrows and protected right, markings at rotaries and left turn lanes are some of the markings on approaches to intersections.4.2.1 Stop Line (M200)Marking M200 must be used at priority intersections controlled by sign R100 (STOP) to indicate where drivers should stop before proceeding into the intersection, having ascertained the major roadway is clear.
STOP intersection Layout The double line is used exclusively a junctions controlled by ³STOP´ signs and in no circumstances should be used merely to give warning of the approach to a major road for which the “GIVE WAY” marking is appropriate.4.2.2. Pedestrain Crossing (M311)Crossing of the carriageway by pedestrians, only at the unauthorized places minimizes the confusion. As a result of this, the number of pedestrian casualties is reduced and the tendency to jaywalk is curbed. The success of pedestrians crossings in controlling both vehicular and pedestrians traffic depends to a greater extent on where and how they are marked. Pedestrian crossings shall be provided at important intersections where conflict exists between vehicular and pedestrian movements. The site should be so selected that the pedestrians are subjected to minimum inconvenience and the vehicular traffic too is not interrupted very often. Marking M311 is used to define an area of roadway that may be used by pedestrians for crossing the roadway at non-signalized crossing areas.
4.2.3. Directional Arrow (M402)In addition to the warning lines on approaches to intersections, directional arrows should be used to guide drivers in advance over the correct lane to be taken when approaching busy intersections whether signal controlled or not. Because, of the low angle at which such markings are viewed, these must be elongated in the direction of the traffic flow to provide adequate legibility. Arrows irrespective of speed to be envisaged. Normally four arrows should be used in sequence in each lane. The direction arrow nearest to the intersection should be 15 m from the stop line or the entrance to the junction. The second arrow should be placed 15 m before the first arrow and similarly for third and forth arrow.
Warning / Deflection Arrow Deflection/warning arrow marking M408 can be used for two purposes: to warn of the approach to a hazard or provide guidance where there is a loss of lanes.
Physical obstructions in a carriageway like traffic island or obstructions near carriageway like signal posts, pier etc. cause serious hazard to the flow of traffic and should be adequately marked. They may be marked on the objects adjacent to the carriageway.
Wherever there is a change in the width of the road, or any hazardous location in the road, the driver should be warned about this situation with the help of suitable road markings. Road markings showing the width transition in the carriageway should be of 100 mm width. Converging lines shall be 150 mm wide and shall have a taper length of not less than twenty times the off-set distance as shown in Fig.15. Throughout the transition area line separating the opposing direction of traffic shall be no-overtaking zone pattern. It should be borne in mind that these lines, in themselves, are not considered to be sufficient warning at such locations. They should always be used to supplement the standard warning strips.
Physical obstructions within the carriageway, such as monuments, transmission poles or towers, trees etc. which constitute a serious hazard to traffic, should not be allowed except under compelling circumstances. All possible measures should be taken to prevent vehicles from colliding with the obstructions. The approach marking to obstructions shall be so designed as to deflect the traffic away from the obstruction by diagonal lines or chevron markings. (Fig.16). The immediate approach to channelising and central median islands may be marked by diagonal/ chevron marking. When the traffic flow in the two sides of markings is in the same direction, chevron marking is appropriate. The colour of these markings shall be yellow. The total length of marking at channelizing islands shall be variable as per site conditions but the length should be sufficient to include at least two chevron/ diagonals. Chevron Marking The immediate approach to channelizing and central median islands may be marked by diagonal/chevron marking described in Fig. 16. When traffic flow on the two sides of markings is in the same direction, chevron marking is appropriate. The colour of these markings shall be yellow. The total length of marking at channelizing islands shall be variable as per site conditions but the length should be sufficient to include at least two chevron/diagonals. Painted channelization can be used to increase efficiency and safety and has the advantage of easy modifications, when warranted by the driver behavior. If a more permanent barrier is required, curbs and islands may be constructed but the painted channelization will serve initially to establish the best layout arrangement before permanent construction is established.
Marking M114 is used to separate adjacent streams of traffic travelling in the same direction in advance of a physical separation. The marking may be used, with the direction of the chevrons reversed, to extend a physical separation to control merging streams of traffic. Marking M115 is substituted for M114 on strategic routes. It may be used at the bifurcation or convergence of two freeways or similar roadways. Markings for Parking The marking of the parking space limits on urban roads promotes more efficient use of the parking spaces and tends to prevent encroachment on places like bus stops, fire hydrant zones etc. where parking is not allowed and is undesirable. Such parking restrictions should be indicated with markings that are solid white lines 100 mm wide. Words TAXI, CARS, SCOOTERS etc. may also be written if the parking area is specific for any particular type of vehicle.
Disabled Parking Bay Symbol Marking M130 shall be used whenever a parking bay is assigned as a disabled parking space in conjunction with sign R200. The marking is located centrally within the bay with the lower edge (bottom of wheel) facing the direction of travel when situated in a parallel parking space. When used within an angled bay (marking M129), the lower edge of the symbol shall face into the roadway (not toward the curb line).
Curb Markings at Intersections Marking M131 can be applied to curbs near an intersection to highlight its presence. The curbs are painted black and white for a standard length of 750 mm (or length of an individual curb face). The markings should extend back from the intersection for a distance corresponding to that for warning lines Use of the marking shall be limited to the approach to intersections, and its use shall be guided by the following:• If clear, effective lighting is present then no curb or edge of roadway marking required• If lighting is not sufficient enough then edge of roadway marking only• In low/no lighting situations then edge of roadway and curb marking can be used if the Overseeing Organization deems them appropriate and use of edge of roadway marking is not effective on its own Where non-standard curbs are present, alternating colors are used in the situations detailed above to retain increased delineation of the intersection.
The material commonly used for pavement, curb object markings is hot applied thermoplastic paints, which are now-a-days specified for roads. Improved night visibility is obtained by the use of minute glass beads incorporated in the markings to produce a retro-reflective´ surface. Other materials that may also be used include pre-fabricated sheet materials, glue-down plastic stripes, metal and plastic inserts-and road studs. The commonly used colours for road markings are white and yellow.9. Systematic Maintenance All road owning/ maintenance agencies shall devise cyclic process for maintenance/ repairing of the road markings. They shall also provide display board giving helpline numbers and responsible officials who could be contacted in case of any complaint. 10. Concluding Recommendations In Qatar numbers of agencies are involved in bad traffic management. However, due to lack of standardized, proper road markings, there are frequent problems in safe and smooth movement of traffic. It is, therefore, essential to adopt uniform standardized road markings on all the roads. It is also important to devise a system whereby the road markings are regularly maintained or repainted, according to time cycle. Subject to approval, the guidelines given herein shall be mandatory for all the road owning, development and maintenance agencies in Qatar.
QTCM Reference Road Marking with Code;
Gate No: 154, Street No: 24,
Doha, Qatar
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