Abstract:
Disclosed are pavement markers and a mobile highway marking apparatus for advancing in a forward direction along a paved surface of a highway for applying a paint stripe to the paved surface and applying pavement markers at intervals on the paint stripe. The marking apparatus includes a dispenser that is configured for moving a sequence of the pavement markers form the bottom of an upwardly extending stack of the pavement markers first in the forward direction and then down a sloped chute in a rearward direction to the paint stripe without turning the pavement markers over.

Description:
CROSS REFERENCE 
       [0001]    This is a division of U.S. patent application Ser. No. 12/749,877, filed Mar. 30, 2010, and is a continuation-in-part of U.S. patent application Ser. No. 12/362,729 filed Jan. 30, 2009. 
     
    
     TECHNICAL FIELD 
       [0002]    This disclosure concerns a retro-reflective pavement marker that is fixed to a base line of roadway marking or “striping” such that an audible and vibratory effect is produced in a vehicle when a wheel of the vehicle drives over the marker, the pavement marker reflects lights from a vehicle to the driver of the vehicle, and concerns the method and apparatus for applying the marker to a highway. 
       BACKGROUND 
       [0003]    It is common in automobile traffic control to use pavement markings for directing vehicles. Typically, solid lines and skip lines are formed on the surface of pavement to guide the drivers of vehicles in safe traffic flow arrangements. 
         [0004]    In order to reduce accidents involving vehicles running off of the road or out of a lane, pavement markings are used that produce an audible and vibratory effect when a wheel of a vehicle drives over the markings. One such pavement marking involves including a small bump at intervals on a base line of the highway. The bumps may be applied by extruding a molten or uncured lump of a specially designed material onto the base line of pavement striping. Upon curing, the lump of material becomes a solid bump and produces the audible vibratory effect when driven over. This bump line approach has been mostly avoided by contractors due to slow application speeds, high material consumption, and excessive cure times as much as fifteen minutes or more. Other problems exist with variations in size and shape of the bump that may be produced, for example, by temperature and viscosity fluctuations. 
         [0005]    It is known that objects may be embedded into a pavement striping to increase light reflectivity in order to make the pavement striping more visible in darkness. As an example, reflective beads such as glass spheres have been applied to pavement striping when it the striping is still in a molten state. The beads that are used to reflect light may be translucent and therefore retroreflective, or the beads may be formed of reflective material. This is effective particularly when the beads are elevated above the pavement surface so that they are not submerged in wet conditions. However, merely embedding retroreflective beads in pavement striping fails to produce a sufficient audible vibration from the striping when a vehicle crosses over the striping. 
         [0006]    As another example, reflective markers, such as those described in U.S. Pat. No. 3,418,896 to Rideout, have been embedded into molten pavement striping. Rideout discloses reflective markers that produce rumbles or bumps when vehicle wheels roll over them. The markers of Rideout have flat upper and lower surfaces and vertical side walls coated with glass spheres. The upper flat surface of the marker is not reflective. When the glass spheres wear off of the side walls, the marker loses its reflectivity and must be replaced. Although Rideout discloses dropping his markers “onto a tacky binder layer with one of the flat sides down,” Rideout fails to disclose a method or an apparatus for dispensing the markers automatically. 
         [0007]    U.S. Pat. No. 4,279,534 to Eigenmann discloses a method and apparatus for applying asymmetrical retroreflective elements to a carrying layer such as a traffic paint film. However, Eigenmann fails to teach a method for applying pavement markers of a larger size to molten pavement striping while avoiding the undesirable defects in the base line material that can occur at higher application speeds. For example, a straight drop of a pavement marker from a vehicle traveling at or above 3 miles per hour (mph) can result in skidding of the marker, which forms a puddle in the base line material. Even at speeds as slow as 1 mph and assuming an effectively disc-shaped marker, if the front, or leading, edge of the marker hits the base line first, the marker tends to flip upside down due to the combination of forces applied by the striping to the marker. Alternatively, if the marker is dropped with too great of a rearward tilt, the marker might bounce, leaving a divot in the base line, and might flip over. My invention includes a pavement marker constructed of material capable of partially melting and fusing with a molten highway striping. 
         [0008]    Thus, this invention addresses the inadequacies of the prior art described above and provides improved pavement markers for the audible and retroreflective marking of highways, and the apparatus and process of applying the markers to pavement striping on highways. 
       SUMMARY OF THE DISCLOSURE 
       [0009]    The method, apparatus and product disclosed herein provide improved road striping for highways over which vehicles pass, including pavement markers in the road striping that are reflective and produce an audible vibration when driven over. 
         [0010]    One form of the disclosure is a pavement marker for the marking of the surface of paved highways formed of a molded mixture comprising light reflective beads and a binder. The pavement marker includes a base surface that becomes the bottom surface for facing downwardly in the road striping, an opposed surface that becomes the top surface for protruding upwardly from the road striping, and a side surface intersecting the base surface and opposed surface. The base surface is effectively flat and has a greater breadth than the opposed surface. The side surface is sloped with respect to the opposed surface at an angle to produce an audible vibration when a wheel of a vehicle engages the opposed surface of the pavement marker. The pavement marker is characterized by some of the light reflective beads being partially embedded in the binder and partially exposed on the opposed surface and on the side surface for reflecting light from the vehicle, and keeping the binder layers from sticking together when stacked, and others of the light reflective beads are totally embedded in the binder material. As the binder material and reflective beads wear away from the opposed and side surfaces of the pavement markers, some of the light reflective beads that were totally embedded in the binder of the pavement marker will become exposed for reflecting light from the vehicle. 
         [0011]    A method disclosed herein is a method for forming highway markings on a paved highway. The highway markings include a base line and reflective pavement markers applied at intervals to the base line. The pavement markers have an effectively flat base surface and an opposed surface. The method may include the following steps. A carrier is advanced in a forward direction along the highway at a predetermined speed in a forward direction. Liquid striping material is applied from a liquid applicator mounted on the carrier to the paved highway to form the base line on the highway. A pavement marker is tilted so that the base surface of the pavement marker is in a tilted attitude and faces in the forward direction. Then the pavement marker is moved along a sloped path directed rearwardly of the forward direction while the base surface of the pavement marker is still in its tilted attitude and facing the forward direction. The pavement marker is applied to the base line, and the pavement marker is tilted back to horizontal as it is applied to the base line so that its base surface is horizontal and embedded as the bottom surface in the molten pavement marking. 
         [0012]    Another feature of this disclosure is an apparatus for forming highway markings including a base line and light reflective pavement markers spaced along said base line. The apparatus includes a carrier for moving along a highway surface in a forward direction. The apparatus may include a liquid applicator mounted on the carrier configured to apply a base line of molten thermoplastic pavement marking to the highway surface. The apparatus further comprises a dispenser for dispensing the pavement markers onto the base line. The dispenser may include a hopper configured to hold a supply of the pavement markers in an upwardly extending stack of the pavement markers. A chute is sloped downwardly from the supply of pavement markers and rearwardly from the forward direction of movement of the carrier for receiving the pavement markers and moving the pavement markers toward the base line when applied to the highway surface. A pusher may be used for moving a pavement marker from the supply of pavement markers onto the chute. 
         [0013]    Another form of the disclosure is a mobile highway marking apparatus for advancing in a forward direction along a paved surface of a highway for applying a base line to the paved surface and applying pavement markers at intervals on the base line. The pavement markers each may include opposed substantially parallel base and opposed surfaces. The marking apparatus includes a paint applicator for progressively applying the base line to the paved surface of the highway as the marking apparatus advances. The marking apparatus further includes a dispenser carried by the marking apparatus for intermittently applying the pavement markers at intervals to the base line that was applied to the paved surface. The dispenser may be configured for moving a sequence of the pavement markers from the bottom of an upwardly extending stack of the pavement markers down a sloped chute in a direction opposite to the forward direction of movement of the highway marking apparatus to the base line without turning the pavement markers over. 
         [0014]    Other objects, features and advantages of the present disclosure will become apparent upon reading the following specification, taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1  is a perspective view of a pavement marker according to one embodiment. 
           [0016]      FIG. 2  is a side view of the pavement marker of  FIG. 1 . 
           [0017]      FIG. 3  is a side view of a dome-shaped pavement marker according to another embodiment. 
           [0018]      FIG. 4  is a top view of the pavement marker of  FIG. 1 . 
           [0019]      FIG. 5  is a bottom view of the pavement marker of  FIG. 1 . 
           [0020]      FIG. 6  is a bottom view of the pavement marker of  FIG. 1  having a grooved texture applied to the base surface according to another embodiment. 
           [0021]      FIG. 7  is a top view of a mold used to form the pavement marker of  FIG. 1  according to one embodiment. 
           [0022]      FIG. 8  is a side cross sectional view of the mold of  FIG. 7 . 
           [0023]      FIG. 9  is a perspective view of a highway surface having a base line and a plurality of pavement markers embedded into the base line. 
           [0024]      FIG. 10  is a side elevational schematic view of the method and apparatus for forming the base line and dispensing the pavement markers. 
           [0025]      FIG. 11  is the side elevational schematic view of  FIG. 10 . depicting a delivery chute having an adjustable slope. 
           [0026]      FIG. 12  is the side elevational schematic view of  FIG. 10 . depicting a delivery chute having a varied angle of descent. 
           [0027]      FIG. 13  is a cross sectional view of a delivery chute according to one embodiment. 
           [0028]      FIG. 14  is a cross sectional view of a delivery chute having a plurality of longitudinal ribs according to one embodiment. 
           [0029]      FIG. 15  is a perspective view of a dispenser of the apparatus for forming a base line on a paved surface. The top wall of the dispenser housing is broken away to expose the interior of the housing and the hopper is expanded above the housing. 
       
    
    
     DETAILED DESCRIPTION 
       [0030]    Referring now in more detail to the drawings, in which like numerals indicate like parts throughout the several views,  FIGS. 1-6  illustrate examples of a pavement marker according to various embodiments. The pavement marker is adapted to be applied to a molten base line of highway striping at intervals, thereby becoming embedded into the base line. In a preferred embodiment, the material of the pavement marker partially melts due to the temperature of the molten base line, fusing the pavement marker to the base line. The pavement marker may be designed to be retroreflective and to produce an audible vibratory effect in a vehicle when a wheel of the vehicle engages the pavement marker.  FIGS. 10-12  and  15  illustrate a method and apparatus for dispensing the pavement markers accurately while traveling at acceptable application speeds of about 3 to 5 miles per hour, without causing undesired effects in the base line material. 
         [0031]    With reference to  FIG. 1 , a pavement marker  100  has a base surface  103 , an opposed surface  106 , and a side surface  109 . The opposed surface  106  and the side surface  109  of pavement marker  100  support partially exposed light reflective beads  112 . The pavement marker  100  is formed of a molded mixture comprising light reflective beads  112 , a binder, and other materials. Light reflective beads  112  may comprise, for example, glass spheres such as AASHTO M-247 specification retroreflective beads, though a wide variety of sizes and refractive indexes of glass spheres could be used. As depicted in  FIGS. 4-6 , in a preferred embodiment, the base surface  103  and the opposed surface  106  have a circular shape, giving the pavement marker  100  an overall disc-like shape. A circular shape has been selected for its simplicity and ability to reflect omni-directionally when put into service, although it is understood that other shapes, such as polygons or domes also may be used. 
         [0032]      FIG. 2  is a side view of the pavement marker  100 . The pavement marker  100  has a base surface diameter  203 , an opposed surface diameter  206 , a thickness  209 , and a wall angle  212 . In a preferred embodiment, the base surface diameter  203  is between 3 and 3.25 inches, which has excellent audibility and visibility characteristics and fits within the four-inch wide base lines most commonly used in highway striping in the United States. In a preferred embodiment, thickness  209  will be one-half inch, which meets specifications for audible pavement markings in Florida, South Carolina, and other states. It is to be understood, however, that the base surface diameter  203  and thickness  209  are nominal values and other sizes may be used as appropriate. 
         [0033]    In a preferred embodiment, the wall angle  212  is 75 degrees. Wall angles  212  from 35 to 80 degrees may be used, and steeper angles are correlated with sharper audible sounds and a more intense vibratory effect. A steeper angle also provides better wet reflectivity for the light reflective beads  212  on the side surface  109 . However, with a wall angle  212  above 75 degrees, the tire impact point on opposed surface  106  and side surface  109  will have less support and may wear more quickly and/or be more likely to fracture. A wall angle  212  of 75 degrees is associated with an audible vibration having an intensity of at least 100 decibels when the vehicle is traveling at or above 55 mph. 
         [0034]    The opposed surface diameter  206  may be determined from the thickness  209 , the base surface diameter  209 , and the wall angle  212 . Preferably, the opposed surface  106  is substantially flat with light reflective beads  112  protruding from the flat opposed surface  106 . But other shapes may be used. 
         [0035]    The side surface  109  of the pavement marker  100  forms an acute angle with the base surface  103  that helps to anchor the pavement marker in the base line  906 , as shown in  FIG. 9 . 
         [0036]      FIG. 3  depicts a pavement marker  300  wherein the opposed surface  303  has a convex dome shape. The pavement marker  300  also has a dome thickness  306 . A slight dome shape provides a larger surface area on opposed surface  303  when compared to opposed surface  106 , and a larger surface area provides better wet retroreflectivity. However, pavement marker  300  may consume more material. Additionally, pavement markers  300  may be more difficult to stack and have less support when stacked, leading to potential breakage. 
         [0037]      FIG. 4  shows a top view of the pavement marker  100 . The light reflective beads  112  have been omitted for clarity.  FIG. 5  shows a bottom view of the pavement marker  103 , wherein the base surface  103  is substantially free of protruding light reflective beads  112  and is effectively flat. By contrast,  FIG. 6  illustrates a bottom view of the pavement marker  103 , wherein the base surface  103  has a surface texture  603 . In this embodiment, surface texture  603  comprises groves that have been cut or stamped into the base surface  103 . Surface texture  603  may also comprise dimples or other surface features. Although not essential, surface texture  603  may aid in keeping the pavement marker  100  secured in the base line material by allowing the pavement marker  100  to settle further into the base line material. It is preferred that the base surface be effectively flat, generally without a surface shape that tends to cause the pavement marker to flip or to roll over when being applied to the highway striping or when being dispensed. Also, the effectively flat base surface  103  of the pavement markers  100  allows the lowermost pavement markers in an upwardly extending stack to move laterally from the bottom of the stock with a minimum of friction. 
         [0038]      FIGS. 7-8  show one example of a mold used in forming pavement markers  100  according to various embodiments.  FIG. 7  illustrates a top view of a mold  700 , while  FIG. 8  illustrates a side cross sectional view of the mold  700 . The mold  700  has an upper surface  703 , a wall surface  706 , and a lower surface  709 , the surfaces together forming a cavity  712 . Mold  700  may be formed out of metal, such as steel or aluminum, by machining or stamping into the desired shape. Also, molds may be made by pressing the shape into a mixture of glass beads themselves held in place by a small amount of tackifier, film former, or water. 
         [0039]    The mold  700  is prepared by first spraying with a solution comprising, for example, five grams of surfactant and ten grams of polyvinyl alcohol per liter. The surfactant functions to reduce surface tension of the water to allow for an even coating. Reflective beads, such as light reflective beads  112 , are applied to the mold  700  and cling to the wet surfaces of the mold  700 . Upon drying, the polyvinyl alcohol in the solution forms a film that holds the reflective beads to the wall surface  706  and the lower surface  709  of the mold  700 . Accordingly, the reflective beads become the light reflective beads  112  of the pavement marker  100  and also prevent the pavement marker  100  from sticking in the mold  700 . 
         [0040]    In various embodiments, the material used in formulating the pavement marker  100  may be similar to that used in the base line in order to ensure proper fusion of the pavement marker  100  with the molten base line. However, pavement markers  100  may be formulated with a higher content of a copolymer, such as ethylene vinyl acetate, to improve toughness and reduce the likelihood of fracture during shipping or application. It may further be desired to raise the softening point slightly to prevent deformation of the pavement marker  100  in extremely hot weather. By using reflective beads within the formulation as well as to coat the cavity  712 , once the light reflective beads  112  wear off of the opposed surface  106  and side surface  109  of the pavement marker  100 , others of the light reflective beads  112  that were initially totally embedded will become exposed when the binder material wears away. 
         [0041]    The following is an example formulation of base line material compared with an example formulation of pavement marker  100  material: 
       Example Base Line Formulation: 
       [0042]      
         [0000]    
       
         
               
               
               
             
           
               
                   
                   
               
             
             
               
                   
                 Maleic modified glycerol ester of rosin 
                 17% 
               
               
                   
                 Titanium dioxide pigment 
                 10% 
               
               
                   
                 AASHTO M-247 glass spheres 
                 40% 
               
               
                   
                 Calcium carbonate filler 
                 29.5%     
               
               
                   
                 Ethylene vinyl acetate copolymer 
                  1% 
               
               
                   
                 Long alkyd oil plasticizer 
                 2.5%  
               
               
                   
                 Resulting softening point: 
                 100 C. 
               
               
                   
                   
               
             
          
         
       
     
       Example Pavement Marker Formulation 
       [0043]      
         [0000]    
       
         
               
               
               
             
           
               
                   
                   
               
             
             
               
                   
                 Maleic modified glycerol ester of rosin 
                 17% 
               
               
                   
                 Titanium dioxide pigment 
                 10% 
               
               
                   
                 AASHTO M-247 glass spheres 
                 40% 
               
               
                   
                 Calcium carbonate filler 
                 28% 
               
               
                   
                 Ethylene vinyl acetate copolymer 
                  5% 
               
               
                   
                 Long alkyd oil plasticizer 
                  2% 
               
               
                   
                 Resulting softening point: 
                 128 C. 
               
               
                   
                   
               
             
          
         
       
     
         [0044]    The pavement marker  100  formulation, such as that given above, is blended and heated to 420 degrees Fahrenheit, or some other temperature, where it liquefies to a syrup-like consistency. The thermoplastic formula is then poured into the cavity  712  of the mold  700  at a rate that will not disturb the coating of reflective beads until the cavity  712  is full. The material quickly solidifies as it cools. Within about 10 minutes, the pavement marker  100  is cool enough to handle, and the mold  700  may simply be inverted to remove the pavement marker  100  from the cavity  712 . 
         [0045]    It is understood that other processes may be used to manufacture pavement markers  100 . Additionally, alternative chemistries, such as hydrocarbon-based formulations, may be used. 
         [0046]      FIG. 9  shows a perspective view of a highway surface  903  having a base line  906 , the base line  906  having a base line width  909 . A plurality of pavement markers  100  are embedded into the base line  906  at intervals  912 . The interval  912  may be, for example, 30 inches, 24 inches, or other distances as may be desired. The base line width  909  may be four inches or some other width as desired. The base line  906  may be any commercially available, preferably thermoplastic, highway marking material, such as Tuffline Alkyd or Ecotherm Alkyd available from Crown Technology, LLC, in Woodbury, Ga. The base line  906  may be applied at a thickness of, for example, 0.10 to 0.11 inches. 
         [0047]    Referring now to  FIGS. 10-12 , shown are side elevational schematic views of the method of forming the base line  906  and dispensing the pavement markers  100 . Carrier  1000  comprises a commercially available single vehicle, such as a truck manufactured by Mark Rite Lines in Billings, Mont., Model 4-4000-DP, that is advanced along the highway surface  903  in the direction as indicated by arrow  1003 . 
         [0048]    A liquid applicator  1006  having a spray head  1009  is mounted to the carrier  1000 . As the carrier  1003  advances, the liquid applicator  1006  applies thermoplastic paint  1012  to the highway surface  903  through the spray head  1009 . The thermoplastic paint  1012  comprises thermoplastic pavement marking material that has been heated to a molten state at between 400 and 425 degrees Fahrenheit. It is understood that different paint materials may require different application temperatures. Furthermore, although the term “paint” is used, “paint” is understood herein to refer to any type of pavement marking material. After application, thermoplastic paint  1012  forms the base line  906  for the highway striping. 
         [0049]    Also mounted to the carrier  1000  is a pavement marker dispenser  1015 . In this embodiment, the pavement marker dispenser  1015  comprises an upwardly extending hopper  1018 , a disc actuator  1021 , and a delivery chute  1024 . The hopper  1018  holds an upwardly extending stack of the pavement markers  100 , the stack being supported by a supporting surface  1027 . The disc actuator  1021  is configured to deliver pavement markers  100  to the delivery chute  1024  at predetermined time intervals based on the speed of the carrier  1000 . Thus, the disc actuator  1021  may be controlled by a commercially available skip timer. 
         [0050]    In the embodiment of  FIGS. 10-12 , the disc actuator  1021  includes a pushing means  1030  for directing the lowermost pavement marker  100  in the hopper  1018  laterally along the supporting surface  1027  in the direction of movement of the carrier  1000  to the delivery chute  1024 . The pushing means  1030  may comprise, for example, an air-actuated sliding shoe. In other embodiments, the disc actuator  1021  may comprise, for example, a rotating helical surface configured to support the stack of pavement markers  100  in the hopper  1018  and to rotate to allow a pavement marker to drop down and be received by the delivery chute  1024 . Other mechanisms may be appreciated for supporting the stack of pavement markers  100  and releasing one of the stack into the delivery chute  1024 . Upon release of a pavement marker  100 , the stack in the hopper  1018  advances downward in the direction of arrow  1031 . 
         [0051]    The pavement markers  100  are to be loaded in the upwardly extending hopper  1018  with their effectively flat base surfaces facing down toward engagement with the upwardly facing opposed surfaces of the pavement markers next below. By the operation of the pushing means  1030 , the pavement markers  100  are given a forward velocity in the direction of arrow  1032  and are received by the delivery chute  1024 . The pavement marker dispenser  1015  is designed to keep the pavement marker  100  positioned with its effectively flat base surface  103  in contact with the parts of the pavement marker dispenser  1015 , and, in particular, delivery chute  1024 . Such positioning tends to avoid abrasive wear that might be caused by the light reflective beads  112  engaging the delivery chute, thereby prolonging the life expectancy of the pavement marker dispenser  1015 . 
         [0052]    Since the upwardly facing opposed surfaces of the pavement markers in the hopper engage the effectively flat base surfaces of the pavement marker next above, the frictional resistance applied to the lowermost pavement marker during lateral movement from beneath the stack is minimized. 
         [0053]    In some embodiments, the delivery chute  1024  may be equipped with a damper  1033  to dampen the impact of the pavement marker  100  at the surface of the delivery chute  1024  and to reduce bouncing of the pavement marker  100  when applied at a high rate of speed. Bouncing of the pavement marker  100  may lead to imprecise placement into the molten base line  906 . The damper  1033  may comprise, for example, rubber bushings or a surface affixed to the delivery chute  1024  by a flexible material, such as silicone or foam. 
         [0054]    When the pavement marker  100  engages the delivery chute  1024  or damper  1033 , the gravitational force pulls the pavement marker  100  downward as shown by arrow  1036 . While sliding down the delivery chute  1024  in the direction of arrow  1039 , the pavement marker  100  gains a horizontal component of velocity in the direction rearward of the movement of the carrier  1000 . Accordingly, when released by the delivery chute  1024  for embedding into the base line  906 , the pavement marker  100  has a forwardly directed component of velocity less than that of the carrier  1000 . Preferably, the pavement marker  100  will have a forwardly directed component of velocity less than 1 mph when the pavement marker  100  contacts the molten base line  906 . By having a net forward ground speed less than that of the carrier  1000 , surfing and skidding of the pavement marker  100  on the base line  906  are reduced. 
         [0055]    When the pavement marker  100  is released from the delivery chute  1024 , the base surface  103  is sloped facing downwardly and forwardly of the pavement marker dispenser  1015 . A slight tilt of between 20 and 35 degrees helps to prevent a number of defects from occurring. For example, if the forwardly facing side surface  109  were to hit the base line  906  first, the pavement marker  100  may flip upside down due to the combination of forces applied to the pavement marker  100 . However, too much tilt, e.g., greater than 40 degrees, may cause the pavement marker  100  to bounce, leaving a divot in the base line  906 , and may cause the pavement marker  100  to flip over. 
         [0056]    The angle of the delivery chute  1024  may be selected based on the desired speed of the carrier  1000 . For example, the carrier  1000  may be moving at a speed of between 2 and 7 mph. It has been observed that highway striping crews prefer to apply pavement markings at a speed of between 3 and 5 mph. Therefore, the length and angle of the delivery chute  1024  and the corresponding rearward velocity may be fixed for the common case, as depicted in  FIG. 10 . Alternatively, as depicted in  FIG. 11 , the angle of the delivery chute  1024  may be adjustable. The delivery chute  1024  may have a slide portion  1103  connected to an upper portion  1106  by means of a hinge  1109 . Therefore, the angle of descent may be varied by moving the slide portion  1103  in the direction of arrows  1112  or  1115 . Additionally, the length of the delivery chute  1024  may be adjustable in some embodiments. In various embodiments, a change in the angle or length of the delivery chute  1024  may be partially or fully automated based on the speed of the carrier  1000 . 
         [0057]    The delivery chute  1024  of  FIG. 12  exhibits a varied angle of descent by having a first slope  1203  and a second slope  1206 . As shown, the first slope  1203  has a steeper angle of descent than the second slope  1206 , but the opposite may be the case in other embodiments. Alternatively, the change in slope may be graduated, producing a curved delivery chute  1024 . 
         [0058]    Referring next to  FIGS. 13-14 , shown are cross sectional views of the delivery chute  1024  according to various embodiments. In particular, the delivery chute  1024  has two side walls  1303  and a sliding surface  1306 . The walls  1303  and/or the sliding surface  1306  may be constructed of plastic, metal, and/or other suitable material. The size and configuration of the walls  1303  and sliding surface  1306  as depicted is merely one example of walls  1303  and a sliding surface  1306 , and the dimensions may vary as desired depending on the pavement marker  100  and other factors. The sliding surface  1306  may be flat as shown in  FIG. 13  or, alternatively, may have a plurality of longitudinal ribs  1403  as shown in  FIG. 14 . The plurality of longitudinal ribs  1403  may be used to reduce the surface area in contact with the pavement marker  100 , thereby reducing friction. The quantity and configuration of the plurality of longitudinal ribs  1403  are presented only as one example of such a friction reducing configuration. 
         [0059]    Referring back to  FIGS. 10-12 , the pavement marker dispenser  1015  and the delivery chute  1024  are positioned on the carrier  1000  and configured so that the pavement marker  100  is released to the molten base line  906  as close to the spray head  1009  as possible, preferably within 10 inches of the spray head  1009 . This positioning is desired because the thermoplastic paint  1012  cools very rapidly and the molten base line  906  needs a sufficiently high temperature to produce a bond between the pavement marker  100  and the molten base line  906 . Preferably, the temperature of the molten base line  906  will be sufficiently high to partially melt the material of the pavement marker  100  so that the partially melted pavement marker  100  will fuse with the molten base line  906 . 
         [0060]    As shown in  FIGS. 10-12 , a reflective bead applicator  1042  having a dispensing head  1045  may be mounted to the carrier  1000 . The reflective bead applicator  1042  releases light reflective beads  1048  through the dispensing head  1045  onto the molten base line  906 . The light reflective beads  1048  may be the same as or different from the light reflective beads  112  used in the manufacture of the pavement markers  100 . The light reflective beads  1048  thereby become embedded into the molten base line  906  with embedded pavement markers  100 , producing a reflective base line  1051 . 
         [0061]      FIG. 15  is a perspective view of a modified pavement marker dispenser  1016 . It includes a modified pusher  1031  that is actuated by pneumatic cylinder  1021  to push the lower most disk-shaped pavement marker  100  from the vertical stack of pavement markers in the hopper  1018  to the discharge opening  1041  in the bottom wall  1042  of the dispenser housing  1043 . 
         [0062]    The pusher  1031  may include a concave pushing surface  1051  that has a radius of curvature that substantially matches the radius of curvature of discharge opening  1041 . When the pusher  1031  is retracted away from the discharge opening  1041  by pneumatic cylinder  1021 , a shelf  1052  having a curved edge  1053  is formed by the bottom wall  1042 . The hopper  1018  is mounted to the top wall  1045  in alignment with the shelf  1052  and the concave pushing surface  1051  of the pusher  1031 . With this arrangement, the hopper  1018  guides the pavement markers  100  downwardly under the influence of gravity until the lowermost pavement marker rests on the shelf  1052 . 
         [0063]    When the lowermost pavement marker  100  is to be dispensed, the pneumatic control system (not shown) actuates pneumatic cylinder  1021 , causing the disk pusher  1031  to move forwardly beneath the hopper  1018  so that its concave edge  1051  engages the lowermost pavement marker, pushing the pavement marker that is resting on the shelf  1052  into registration with the discharge opening  1041 . This causes the lowermost pavement marker to fall through the discharge opening  1041 , where it engages the delivery chute  1024 , sliding down the delivery chute as indicated by arrow  1039 , as described before. 
         [0064]    The thickness of the pusher  1031  is less than the thickness of the pavement markers  100  so that the next oncoming pavement marker tends to engage the top surface of the pusher  1031  when the pusher  1031  has just discharged the previous pavement marker through the discharge opening  1041 . When the pneumatic control system reverses the pneumatic cylinder  1021  to withdraw the pusher  1031  away from the discharge opening  1041  and back into alignment with the hopper  1018 , the pavement marker that is now lowermost in the hopper  1018  will move downwardly to rest on the shelf  1052 , in proper position for the next cycle of the dispenser. 
         [0065]    The placement of the discharge opening  1041  close to the pusher  1031  reduces the longitudinal length of the dispenser  1015 . 
         [0066]    In order to vary the velocity of the pavement markers  100  exiting the dispenser, the delivery chute  1024  may be pivoted about its pivot pins  1060  that extends through the side aprons  61  that straddle the delivery chute  1024 . Positioning pins  1062  extend through one of the openings, such as opening  1063 , to extend behind the delivery chute  1024 , thereby supporting the delivery chute at a desired angle with respect to the pivot pin  1060 . 
         [0067]    Although preferred embodiments of the invention have been disclosed in detail herein, it will be obvious to those skilled in the art that variations and modifications of the disclosed embodiments can be made without departing from the spirit and scope of the invention as set forth in the following claims.