AU1137800A - Improvements in road barriers - Google Patents

Description

WO 00/28148 PCT/AU99/00881 Improvements in Road Barriers Field of the Invention This invention relates to an improved road barrier. 5 Background of the Invention Road barriers are commonly used to divide oppositely moving traffic lanes. Road barriers are also used to line the edges of a road to separate traffic from pedestrians, or from areas where road works or construction is 10 being carried out. Most of the existing road barriers in use today, are so called "New Jersey" style barriers which have a wider base portion from which the walls of the barrier extend upwardly in a generally vertical plane. Originally, New Jersey style barriers were made in concrete such as is described in US patent No 4059362. More recently hollow road barriers 15 made from semi-rigid plastic material, usually polyethylene, which can be filled with water to increase their weight have been developed. Examples of such barriers are disclosed in AU 664774, AU 647189, and AU-A-47345/93. Road barriers are discrete elements typically about 4 to 6 feet long which are assembled and linked together end to end in long lines along the 20 edge of a road or between two lines of traffic moving in opposite directions. The principal function of a road barrier, particularly when used as a crash barrier, is to prevent a motor vehicle crossing the line of the barriers and also to redirect a vehicle which might swipe or contact the barriers back into that vehicle's line of traffic along which it is supposed to be travelling. 25 However, one problem with lines of moulded plastic barriers, is that when a vehicle does swipe or impact the barrier, a longitudinal stretch occurs in the line of barriers and the barriers deflect outwardly and curve away from the vehicle. Because the line of barriers is formed from discrete elements, the line of barriers behaves like a wave forming a curve in the 30 longitudinal form. This is a major problem with virtually all moulded plastic barriers which limits the majority of such road barriers to being suitable for use only where crash resistance is not mandated. This severely restricts their use, as crash resistance is necessary for roadside applications. 35 In order to make the barrier pass the impact test for roadside use, it becomes necessary to reinforce the barrier within an internal frame, typically WO 00/28148 PCT/AU99/00881 2 made of metal, such as is shown in AU 47345/93. which is the only patent document of those referred to above which discloses a moulded plastic road barrier which would currently meet the Australian crash resistance test. The internal frame increases the rigidity of the barrier and strengthens the barrier 5 against bending. Steel cables 49 are fixed to each end of the frame of each barrier. Those cables define loops. In the moulded barrier, pin receiving openings match up with the loops created by the cables and the loops and pin receiving openings of one barrier are then aligned with the equivalent holes and loops on the end of an adjacent barrier. A rigid pin is dropped 10 through the holes linking not only the barriers together but also the frames of the barriers together. Typically an additional wire may extend along the top of the barrier to provide further longitudinal reinforcement to the barrier. The linking of steel frames of the barriers together, rather than just the plastic moulded barriers, means that this type of barrier is sufficiently 15 resistant to longitudinal stretch to correctly redirect cars into the line of traffic without forming a wave in the line of barriers. However, the fact that the barrier requires an internal frame, substantially increases the cost of the barrier and the complexity of the manufacturing process. The barriers also weigh around 65 kg largely due to 20 the weight of the internal metal frames. The weight of the barriers makes manhandling the barriers more difficult particularly when unloading the barriers from trucks onto a roadway. Manhandling heavy barriers from a truck also carries the risk of injury, particularly of back injury, to the persons doing the unloading. 25 A second problem with road barriers, is that when used for traffic applications, where they are required to withstand the impact of vehicles and the like, the barriers must be "full" of a relatively weighty fluid in order to give the barriers sufficient mass to resist deflection and deformation. Typically, this is done by filling the barriers with water. If the barriers have 30 not been filled with sufficient water or water leaks from the barrier, the performance of the barrier is prejudiced. It is important those persons responsible for highway safety can check roadside barriers to ensure that the barriers contain sufficient water. At present, there is no easy way of checking that hollow barriers do contain sufficient water. 35 It is an object of the present invention to address the problems of the prior art discussed above and provide an improved road barrier.

WO 00/28148 PCT/AU99/00881 3 Summary of the Invention Thus, in accordance with a first aspect of the present invention there is provided a road barrier defining an elongate container means configured to receive and hold a volume of fluid material such as water, the barrier being 5 made from a plastics material and comprising: a base; first and second end walls, each of said end walls having means for releasably coupling the barrier in end to end relation with a like barrier; side walls, a central longitudinal axis extending along the length of the 10 barrier from the first end wall to the second end wall; a top; and means to enable the barrier to be filled with a liquid and for enabling liquid to be discharged from the barrier, characterised in that in the side walls of the barrier define a lower face which is inclined and extends 15 outwardly away from the central longitudinal axis of the barrier, a step portion which extends inwards towards the central longitudinal axis of the barrier and an upper inclined face located above the top step portion which extends away from the central longitudinal axis of the barrier. The provision of the inclined faces has the effect of tending to force 20 the wheels of cars which come into contact with the barrier back down onto the road. If a wheel does manage to ride up the lower portion of the side wall such that it rests on the step portion, the upper inclined face tends to force the wheel back down onto the road and push the wheel off the step portion. The lower inclined face may be inclined at an angle which is relatively 25 nearer to vertical, say 100 to 300, typically around 200, than the upper inclined face which might be inclined at 300 to 50o to the vertical, typically around 350. It is preferred that the inclined faces define a series of ribs and channels to reduce the contact area of the faces. The ribs are preferably rounded. 30 The provision of the ribs reduces the available contact area of the barrier with vehicle wheels and may reduce grip between the wheel and the barrier and may reduce the likelihood of the wheel riding up on the barrier. In a preferred embodiment, the means for releasably coupling the barrier in end to end relation with a like barrier, include a plurality of 35 mounting means or reinforced areas, one mounting means being located at each side of both ends of the barrier adjacent the end of the barrier, at the WO 00/28148 PCT/AU99/00881 4 base of the barrier and at the top of the barrier adjacent the upper inclined faces, the mounting means being suitable for mounting a rigid plate such as a metal plate or the like to the barrier to enable one barrier to be connected on both sides to the mounting means of another adjacent barrier in end to end 5 relation. The means for releasably coupling the barrier may be applied to barriers other than those embodying the first aspect of the present invention, therefore in a second aspect of the present invention there is provided: a road barrier including an elongate container means configured to 10 receive and hold a volume of fluid material such as water, the barrier being made from a plastics material comprising: a base; end walls; side walls extending upwardly from the base, each of said end walls 15 having means for releasably coupling the barrier in end to end relation with a like barrier; a top; and means to enabling the barrier to be filled with a liquid and for enabling liquid to be discharged from the barrier; and 20 wherein the means for releasably coupling the barrier in end to end relation with the like barrier include a plurality of mounting means or reinforced areas, one mounting means being located at each side of both ends of the barrier adjacent the end of the barrier, the mounting means being suitable for mounting a rigid plate, such as a metal plate or the like, to the 25 barrier to enable one barrier to be connected on both sides to the mounting means of another adjacent barrier, in end to end relation. Ideally, the mounting means should be located as close as possible to the end of the barrier, typically 50 to 100 mm from the end. In a preferred embodiment the mounting means comprises a cylinder 30 having an annular cross-section and defining an internal bore which is open at one end which faces the exterior of the barrier and its other end defines an external flange which locates and retains the cylinder in the barrier. The rigid plate may be a 5 mm thick steel plate defining one or more apertures adapted to receive a steel bolt. Depending on the location of the 35 reinforcing means in the barriers, the apertures are typically spaced about WO 00/28148 PCT/AU99/00881 5 100 mm apart so that the rigid plates can be fixed between two adjacent barriers by means of threaded bolts screwed into the mounting means. In addition to the linking means defined at the base of the road barrier, the barrier may also include S shaped end portions which interlock with 5 corresponding S shaped portions on an adjacent barrier, in an arrangement in which one male portion is provided at the base of an end adjacent a female portion laterally spaced from the male portion, with a female portion provided above the male portion in the upper part of the end and laterally adjacent, a further male portion, Apertures may be provided extending 10 through the centre of the male portions adapted to receive a threaded bolt connecting the barriers together. The bolts is additional to the linking means defined at the base and the top of the barrier. Thus in a preferred aspect of the present invention, instead of requiring an entire framework to achieve the necessary crash resistance for a 15 line of barriers, all that is required is to mould into each of the four corners of the barrier, a threaded resilient insert to allow the adjacent barriers to be linked together by means of a resilient substantially non-stretchable linkage such as thick steel plate. The steel plate will not stretch and effectively the stretching force applied to the barriers is born by both the steel plates and the 20 entire cross section of the road barrier and this prevents longitudinal stretch as well as preventing the barriers from buckling due to stretching of the plastic barrier. In a third aspect, the invention also provides a road barrier including a longitudinally extending container having a base portion, a pair of side walls 25 and a pair of end walls and a top portion, said container being substantially hollow and formed from a plastics material whereby the container is self supporting and has a predetermined shape and wherein the road barrier includes a water level indicator comprising a float, having a base portion, an upper portion which is typically made from a readily visible material of a 30 visually striking colour such as yellow and which preferably contrasts with the colour of the road barrier, the float having end portions which are broader than a mid portion between those two ends which mid-portion is adapted to be received in a sleeve fixed to the barrier which at one end defines a flange portion which is sufficiently wide to allow the mid portion to extend 35 therethrough but is narrower than the end portions of the float. The float means provides a readily visible indicator of the state WO 00/28148 PCT/AU99/00881 6 of the barrier (filled or unfilled) and avoids the need for close inspection of the barrier which is a problem with prior art barriers as discussed above. Typically the base portion and upper portion are made separately from moulded polyethylene, and most typically made in a rotational moulding 5 process. The base portion may be a generally hollow cylinder which at one end defines a internally threaded bore. The upper portion may define a rotationally moulded cylinder of polyethylene having a wide end portion stepping down to a narrower mid portion at whose end is defined a moulded 10 screw thread which adapted to mate with the bore defined in the base portion. The sleeve may be formed of glass reinforced nylon and at one end opposite from the flange, may define a second flange defining screw holes or the like for attaching the flange around an aperture in the top of the road barrier. 15 Brief Description of the Drawings The invention will now be described, by way of example only, and with reference to the accompanying drawings in which: Figure 1 is an isometric view of a barrier embodying the present 20 invention; Figure lA is a schematic close-up of the connector means embodying the present invention also showing internal details of the barrier; Figure lB shows a link plate; Figure 2 is an end view of the barrier as shown in Figure 1 viewed from 25 the right; Figure 3 is an enlarged view of ribbing present on a lower part of the barrier of Figure 2; Figure 4 is an enlarged view of ribbing present on an overhanging upper part of the barrier of Figure 2; 30 Figure 5A is a schematic illustration showing a relatively small car wheel base adjacent the barrier embodying the present invention; Figure 5B shows the relatively small car wheel base partly riding up on the barrier; Figure 6A is a schematic illustration showing a relatively large car 35 wheel base adjacent the barrier; and WO 00/28148 PCT/AU99/00881 7 Figure 6B shows the relatively large car wheel base riding up over part of the barrier. Figure 7 is a schematic side view of a float embodying aspects of the present invention. 5 Detailed Description of a Preferred Embodiment Referring to the drawings, Figure 1 is a isometric view of a road barrier embodying the present invention, generally indicated at 10. The barrier may be rotationally moulded from polyethylene and with reference to Figure 2 10 includes a base 12, side walls 14a and 14b, a top 16, and ends 18a and 18b. The barrier also includes four relatively large generally rectangular through apertures 20 located in an upper part of the barrier and five relatively smaller generally circular through apertures 21 located in a relatively lower part of the barrier. The through apertures improve the rigidity of the barrier and its 15 ability to be self supporting, particularly when it is filled with a liquid such as water. The barrier includes a hole 22 defined in the top 16 which can be used for pouring water into the container. Close to the base of the container is a drain hole closed with a bung 24 which can be used to drain liquid from the barrier. The upper end of the barrier defines two moulded recesses 25 20 which can be used to receive posts for crowd control security fences, or signage, warning lights or the like. As can be seen from Figure 1, each end of the barrier is generally S shaped defining an upper semi-cylindrical male portion 26 laterally adjacent a corresponding female semi-cylindrical aperture 28 with a similarly 25 arranged but larger, male and corresponding female apertures 30 and 32 respectively, disposed below the upper male portions and female aperture 26, 28 respectively. A hole runs through the centre of each male portion which is adapted to receive a bolt 34 for linking the barriers together. Typically, the bolt will be about 30mm diameter and 180mm long. A level indicator 36 is 30 located at the top of the barrier, and is described in more detail below. However, as discussed in the introduction to this application, merely linking the barriers together with the bolts 34 would not be sufficient to prevent a linked line of the barriers from stretching when side swiped or hit by a vehicle which can potentially cause barriers in the longitudinal string of 35 barriers to deflect into the path of traffic. Accordingly, and with particular reference to Figures 1A and lB, means are provided for connecting a plate or WO 00/28148 PCT/AU99/00881 8 latch to the barrier at each bottom corner of the barrier. The means may include a brass insert comprising a hollow cylinder 40 having an internally threaded bore and defining a hexagonal flange 42 at one end. One such insert is placed at what are to be each of the four corners of the base of the 5 barrier and the four corners of the top of the barrier before moulding. Thus each barrier has eight inserts, one being located at each of its eight corners. During the rotational moulding process when the barrier is moulded, polyethylene 43 will coat and solidify around the insert. In the moulded barrier the flange 42 helps to retain the insert in place in the barrier, with the 10 hexagonal head 42 preventing the insert from rotating about its longitudinal central axis. A latch plate, most preferably a 5mm thick steel latch plate 44 also shown in Figure lB is bolted to one of the inserts by means of a bolt 46 (refer to Figure 1) having an appropriate thread size and diameter. In Figure 1A, the latch plate is shown in an engaged position and also in a disengaged 15 or raised position in dashed outline. The latch plate 46 includes a hole 47 through which the bolt passes and a hook portion 48 defining an external ramp surface 48A. The corner of the barrier which is to be adjacent may have a bolt having a head and part of its shank projecting from its insert. The hook end of the latch plate 44 defines a generally elongate recess 49. 20 Typically the recess allows about a 3mm play either side of the bolt. Thus when two adjacent barriers are pushed together, the head or shank of the bolt will cause the hook portion 48 to ride up along the ramp surface 48A at the hooked end of the plate and subsequently, drop down over the shank of the bolt "engaging" the bolt in the recess. The 3mm play is too small to 25 significantly affect the performance of a linked line of the road barriers when side swiped by a vehicle. In a variant of the invention, not illustrated, plates rather than latches, may be simply bolted between two barriers using bolts and the inserts. In a yet further variant, again not shown, two pairs of inserts may be provided at each corner which may then be linked by a plate having 30 four apertures. Use of latch plates does however make the barriers easier to use and install. Typically, the plate 44 is around 170mm long with the gap between the centres of the apertures 47 and 49 being about 100mm. The plate may be around 5mm thick. When a line of barriers is assembled in end to end 35 configuration with two plates each side linking the juxtaposed ends of the barriers, the line of barriers will not stretch significantly under impact and WO 00/28148 PCT/AU99/00881 9 the line will not project the vehicle under impact across the line of traffic, but redirect it broadly into the original direction of travel. Turning now to Figure 2, it can be seen that in transverse cross-section the barrier of the present invention is different from the standard New Jersey 5 road barrier cross-section. In particular, the barrier defines a base or pedestal area 50 typically having a width of about 600 mm and a height of about 164 mm. Above the base area, a first lower side wall or face 52 extends upwardly and outwardly away from the central axis of the barrier to a height of about 375 mm from 10 the bottom of the barrier. The top part of the lower side wall is further away from the central axis A of the barrier than the lowermost part of the side wall and it overhangs part of the base 50. With reference to Figure 3, it can be seen that the lower side wall comprises a series of ribs 56 separated by relatively deep rounded channels 58. The deep rounded channels assist in 15 providing rigidity to the barrier, particularly when it is filled with water. The ribs have rounded corners. The length "X" shown in Figure 3 is typically around 16 mm. This ribbing reduces the contact area available when a car tyre contacts the lower side wall, as will be explained later with reference to Figures 5A, 5B and 6A, 6B. 20 A step portion 54 is inclined at an angle of approximately 150 to the horizontal and extends from the lower side wall towards the central axis A. A slightly kinked mid-section 60 is defined at the top of the lower side wall/step portion 54 and extends upwardly and slightly inwardly towards the centre of the barrier. The mid section terminates at a height of about 690 25 mm from the bottom of the barrier. The top of the barrier sidewall includes an overhanging upper wall or face 62 which is oriented outwardly from axis A at an angle of approximately 350 to the vertical. The total height of the barrier is about 925 mm. With reference to Figure 4, the upper wall section also comprises a series of ribs 66 and channels 68. The ribs are rounded 30 (length Y is about 20 mm) to reduce the potential area of contact with a vehicle tyre. The channels are shallower than the channels 58 in the lower side wall. The hydrostatic pressure at the top of the barrier is lower than the hydrostatic pressure at the base so the channels do not have to provide as much rigidity to the barrier as the channels 58 in the lower part of the 35 barrier.

WO 00/28148 PCT/AU99/00881 10 The provision of the angled lower wall 52 and upper wall 60 have the affect of directing the wheels of a vehicle which might contact the barrier downwards back onto the road, in contrast with the traditional New Jersey style barrier, where because of the angle of the barrier, such contact tends to 5 cause a car wheel to ride up the barrier wall when it brushes the barrier wall. A wheel riding up the barrier wall is dangerous as it makes the vehicle unstable. It is particularly dangerous if the car reaches the top of the barrier or crosses over the barrier. Figures 5A to 6B illustrate how the barrier may react to contact with 10 small and large cars. A typical relatively small car an illustrative example of which is shown in Figure 5A, may have a 1500 mm wheelbase, a tyre diameter of about 560 mm and tyre width of about 165 mm. A relatively larger car wheelbase, an illustrative example of which is shown Figure 6A might have a wheelbase of 1680 mm, and 635 mm diameter tyres having a 15 width of about 205 mm. The central axis of the tyres of both cars will typically be below the step portion. If the wheel of the relatively small or relatively larger car does manage to rise up past the lower wall section, it may then be trapped on the step portion 54, as shown in Figures 4B and 5B. Advantageously, only a small part of the step 54 is available to support the 20 wheel, particularly in the case of larger cars, see Figure 5B. This increases the likelihood that the wheel will slip off back onto the road. In the case of the small car if the car wheel does ride up onto the step 54, the axle is then angled at about 200 to the road surface. With the large car wheelbase, the angle is about 250. In both cases gravity will tend to force the wheel back 25 down onto the road. The upper wall section 62 also tends to force the car down onto the road. The upper wall section 62 may also wedge cars which hit the barrier onto the road. If the mudguards and/or bonnet of the car come into contact with the upper wall section 62 and this may cause a wedge effect which will 30 prevent the body of the car from lifting beyond the upper wall section. The particular shape of the barrier also provides added strength to the barrier without requiring the steel frame of AU 47345/93. A yet further innovation in the barrier is shown in Figure 1 and in more detail in Figure being the float assembly 36. The float assembly 35 includes a lower float portion 102 which comprises a rotationally moulded generally hollow, closed polyethylene cylinder defining cylindrical side WO 00/28148 PCT/AU99/00881 11 walls, a base and at its upper end, an internally threaded bore, 102a which is adapted to receive a lower threaded tubular portion 103 of an upper part of the float 104 which is also made from rotationally moulded polyethylene, preferably in a bright colour such as yellow. The colour should preferably 5 contrast with the colour of the road barrier, which will typically be red and /or white. The upper part of the float has a first cylindrical portion 106 which steps down to a narrower cylindrical portion 108. The float assembly is mounted inside a sleeve 110 which is typically made from glass reinforced 10 plastic which includes an upper external annular flange 112 which includes a series of holes for use in securing the flange to the body of the road barrier 10 with screws or the like. The sleeve also defines a lower internally directed flange 114 about an aperture which is slightly larger than the central portion 108 of the float assembly but is narrower than the upper 106 and 15 lower portion 102 of the float assembly. Thus the float is able to move up and down in the sleeve between two positions where the ends 108a and 108b of the mid-portion 107 contact flange 114. Figure 5 shows a situation in which the road barrier is sufficiently full of water 120 that end 108b contacts the flange 114 and the marker 104 20 projects from the upper end of the barrier and be easily visible for "drive by" inspection. When the barrier is empty, or insufficiently full, the upper end 108 of the mid-portion will contact the flange 114 and the upper most end of the marker 104 will be below the level of the flange 112 indicating on a "drive by" inspection that the barrier contains insufficient water. 25 The dimensions of the barrier described above may be varied and suitable materials other than those described may be substituted for the materials used to make the specific embodiment described above. It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in 30 the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims (15)

1. A road barrier including an elongate container means configured to receive and hold a volume of fluid material such as water, the barrier being made from a plastics material and comprising: 5 a base; first and second end walls, each of said end walls having means for releasably coupling the barrier in end to end relation with a like barrier; side walls, a central longitudinal axis extending through the barrier from the first end to the second end; 10 a top; and means to enable the barrier to be filled with a liquid and for enabling liquid to be discharged from the barrier, characterised in that in the side walls of the barrier define a lower face which is inclined and extends outwardly away from the central longitudinal axis of the barrier, a step 15 portion which extends inwards towards the central longitudinal axis of the barrier and an upper inclined face located above the step portion which extends away from the central longitudinal axis of the barrier.

2. The road barrier of claim 1 wherein the lower inclined face is inclined at an angle of about 100 to 300 to an axis extending perpendicular to the base. 20

3. The road barrier of claim 1 or claim 2 wherein the upper inclined face is inclined at an angle of 300 to 500. to an axis extending perpendicular to the base.

4. The road barrier of any preceding claim wherein the lower and upper faces define a series of ribs and channels. 25

5. The road barrier of any preceding claim wherein the means for releasably coupling the barrier in end to end relation with a like barrier, include a plurality of mounting means with one mounting means being located at each side of both ends of the barrier adjacent the end of the barrier, at the base of the barrier and also at the top of the barrier, the mounting 30 means being adapted for mounting a rigid plate such as a metal plate or the like to the barrier to enable one barrier to be connected on both sides to the mounting means of another adjacent barrier in end to end relation.

6. A road barrier including an elongate container means configured to receive and hold a volume of fluid material such as water, the barrier being 35 made from a plastics material comprising: a base; WO 00/28148 PCT/AU99/00881 13 two side walls; two end walls extending upwardly from the base, each of said end walls defining means for releasably coupling the barrier in end to end relation with a like barrier; 5 a top; and means to enabling the barrier to be filled with a liquid and for enabling liquid to be discharged from the barrier; and wherein the means for releasably coupling the barrier in end to end relation with the like barrier include a plurality of mounting means, one 10 mounting means being located at each side of both ends of the barrier adjacent the end of the barrier, the mounting means being adapted for mounting a connection means to the barrier to enable one barrier to be connected on both sides to the mounting means of another adjacent barrier, in end to end relation. 15

7. The road barrier of claim 6 wherein the mounting means comprises a cylinder having an annular cross-section and defining an internal bore which is open at a first end which faces out from the barrier and defines an external flange which locates and retains the cylinder in the barrier at a second end.

8. The road barrier of claim 7 wherein the cylinders are located about 50 20 to 100 mm from the end walls of the barrier.

9. The road barrier of claim 6, 7 or 8 wherein the connection means comprise a latch plate defining at least one aperture adapted to receive a bolt.

10 The road barrier of claim 9 wherein the latch plate defines a hook portion at one end. 25

11. The road barrier of any one of claims 6 to 10 further including generally S shaped end portions which interlock with corresponding S shaped portions on an adjacent barrier, in an arrangement in which one male portion is provided at the base of an end adjacent, a female portion laterally spaced from the male portion, with a female portion provided above the male 30 portion in the upper part of the end and laterally adjacent, a further male portion is provided, and wherein an apertures extends through the centre of the male portions which is adapted to receive a threaded bolt connecting the barriers together.

12. A road barrier including a longitudinally extending container having a 35 base portion, a pair of side walls and a pair of end walls and a top portion, said container being substantially hollow and formed from a plastics material WO 00/28148 PCT/AU99/00881 14 whereby the container is self supporting and has a predetermined shape and wherein the road barrier includes a water level indicator comprising a float, having a lower portion, an upper portion which contrasts with the colour of the road barrier, the float having end portions and a mid portion, the end 5 portions being broader than the mid portion between said mid-portion being located in a sleeve fixed to the barrier, and wherein one end of the sleeve defines a flange portion defining an aperture having a width which is sufficiently wide to allow the mid portion to extend therethrough but is narrower than the broader end portions of the float. 10

13. The road barrier of claim 12 wherein the lower portion and the upper portion are made separately from moulded polyethylene.

14. The road barrier of claim 12 or claim 13 wherein the lower portion comprises a generally hollow cylinder having a first end and a second end and wherein an internally threaded bore is defined at the second end.

15 15. The road barrier of any one of claims 12 to 14 wherein the upper portion defines a rotationally moulded cylinder of polyethylene having a relatively wider end portion stepping down to a narrower mid portion at whose end is defined a moulded screw thread which adapted to mate with the bore defined in the lower portion. 20