Patent Publication Number: US-11639157-B2

Title: Brushless car wash system including a telescoping unit for washing top and rear surfaces of vehicles

Description:
BACKGROUND 
     1. Field of Art 
     The present disclosure generally relates to car wash systems for vehicles, and more specifically to automated brushless car wash systems. 
     2. Background of the Invention 
     Car wash systems are used to clean the exterior of vehicles using at least water and soap. One type of automated car wash systems is a tunnel car wash system (e.g., conveyor system). In a tunnel car wash system, a vehicle is driven onto a conveyor of the tunnel car wash system. The conveyer moves the vehicle through the tunnel of the tunnel car wash system where the different steps for washing the vehicle are performed from the initial step of pre-soaking of the vehicle with water to the final step of drying the vehicle. 
     Tunnel car wash systems typically use brushes, water, or a combination of brushes and water to wash vehicles. Using brushes to wash vehicles may damage the surface of the vehicle as the brushes contact the paint of the vehicles to remove any dirt, debris, and/or road film on the surface of the vehicles. The damage may include undesired scratches or swirl marks on the paint of the vehicles to broken parts on the vehicle as the brushes are caught on the parts during washing. 
     While certain conventional tunnel car wash systems may use high-pressure water (e.g., brushless) to wash vehicles to avoid damage on the paint of the vehicles, conventional brushless tunnel car wash systems typically are not capable of thoroughly cleaning the vehicles to remove road film on the vehicles. Thus, conventional tunnel car wash systems are unable to sufficiently clean vehicles. 
     SUMMARY 
     A two-stage brushless car wash system is disclosed. The two-stage brushless car wash system includes a first wash stage apparatus and a second wash stage apparatus that are independently controlled to wash an exterior of a vehicle. Both the first wash stage apparatus and the second wash stage apparatus account for the contour of the vehicle to enhance washing performance. 
     In one embodiment, the first wash stage apparatus is brushless and uses high-pressure water to wash upper surfaces of the vehicle including the front, top, and rear surfaces of the vehicle while accounting for the contour of the upper surfaces of the vehicle such that the first wash stage apparatus is in a constant proximity (e.g., within a distance range) to the upper surfaces of the vehicle during washing. The second wash stage apparatus is also brushless, and uses high-pressure water to wash the side surfaces of the vehicle after the first wash stage apparatus has completed washing the upper surfaces of the vehicle. Similar to the first wash stage apparatus, the second wash stage apparatus also accounts for the contours of the side surfaces of the vehicle during washing such that the second wash stage apparatus is in a constant proximity (e.g., within a distance range) to the side surfaces of the vehicle during washing. 
     In one embodiment, the first wash stage apparatus includes a wash unit that washes the upper surfaces of the vehicle. The height of the wash unit is adjusted based on the contour of the upper surfaces of the vehicle. By adjusting the height of the wash unit as the wash unit sprays the upper surfaces of the vehicle with water, the wash unit of the first wash stage apparatus is able to stay within a distance range from the upper surfaces of the vehicle thereby increasing the wash performance of the first wash stage. 
     In one embodiment, the height of the wash unit included in the first wash stage apparatus is adjusted using a telescoping unit (e.g., a height adjusting unit). The telescoping unit maybe be expanded or contracted according to the contour of the upper surfaces of the vehicle. In one embodiment, the telescoping unit is tilted at an angle. By tilting the telescoping unit, the telescoping wash unit is capable of adjusting the height of the wash unit so as to maintain a predetermined distance range to the rear surface of the vehicle as the vehicle moves away from the first wash stage. Thus, rear wash performance of the vehicle is enhanced. 
     In one embodiment, the second wash stage apparatus has a variable width. By having a variable width, the second wash stage may adjust its width according to the width of the vehicle being washed. By adjusting the width of the second wash stage, a wash unit included in the second wash stage may stay within a distance range from the side surfaces of the vehicle thereby enhancing wash performance. In one embodiment, the width of the second wash stage is adjusted due to physical contact between the second wash stage and the tires of the vehicle. The contact between the second wash stage and the tires sets the width of the second wash stage according to the width of the vehicle. 
     In one embodiment, a two-stage brushless car wash system comprises: a first brushless wash stage apparatus configured to wash a plurality of upper surfaces of an exterior of a vehicle, the first brushless wash stage apparatus including a plurality of nozzles whose height is adjusted a plurality of times as the plurality of nozzles spray the plurality of upper surfaces of the vehicle with water, the height of the plurality of nozzles adjusted according to a contour profile of the plurality of upper surfaces of the vehicle; and a second brushless wash stage apparatus configured to wash a plurality of side surfaces of the exterior of the vehicle independently from the first brushless wash stage apparatus, the second brushless wash stage including a plurality of nozzles that spray the plurality of side surfaces of the vehicle with water according to contours of the plurality of side surfaces of the exterior of the vehicle. 
     In one embodiment, a two-stage brushless car wash system comprises: a first brushless wash stage apparatus configured to wash a plurality of upper surfaces of a vehicle, the first brushless wash stage apparatus including a plurality of first nozzles that are controlled to follow along a contour of the plurality of upper surfaces of the vehicle as the plurality of first nozzles spray the plurality of upper surfaces of the vehicle with water; and a second brushless wash stage apparatus configured to wash a plurality of side surfaces of the vehicle that are distinct from the plurality of upper surfaces of the vehicle, the second brushless wash stage including a plurality of second nozzles that are independently controlled from the plurality of first nozzles of the first brushless wash stage to spray the plurality of side surfaces of the vehicle with water according to a contour of the plurality of side surfaces. 
     In one embodiment, a two-stage brushless car wash system comprises: a conveyor configured to transport a vehicle through the two-stage brushless car wash system; a first brushless wash stage apparatus configured to wash a rear surface of the vehicle using a plurality of first nozzles included in the first brushless wash stage, the plurality of first nozzles configured to spray water as the plurality of first nozzles follow a contour of the rear surface of the vehicle while the vehicle moves through and away from the first brushless wash stage apparatus; and a second brushless wash stage apparatus configured to wash a plurality of side surfaces of the vehicle using a plurality of second nozzles that spray the plurality of side surfaces of the vehicle with water. 
     In one embodiment, a brushless car wash system for washing a vehicle comprises: a wash unit configured to spray water on a plurality of upper surfaces of an exterior of the vehicle to wash the vehicle; and a height adjustment unit coupled to the wash unit at a first end of the height adjustment unit and configured to adjust a height of the wash unit as the plurality of upper surfaces of the exterior of the vehicle is washed, the height adjustment unit tilted at a fixed angle away from a front of the vehicle, the fixed angle measured with respect to a reference that is perpendicular to ground. 
     In one embodiment, a brushless car wash system for washing a vehicle comprises: a light curtain sensor configured to sense a plurality of height points of a plurality of upper surfaces of an exterior of the vehicle along a length of the vehicle, the light curtain sensor tilted at an angle toward a front of the vehicle, the angle measured with respect to a reference that is perpendicular to ground; a wash unit configured to spray water on the plurality of upper surfaces of the vehicle to wash the vehicle; and a height adjustment unit coupled to the wash unit at one end of the height adjustment unit and configured to adjust a height of the wash unit according to the plurality of height points as the vehicle is moved, the height adjustment unit tilted at an angle that corresponds to the angle of the light curtain sensor, the angle of the height adjustment unit measured with respect to the reference that is perpendicular to ground. 
     In one embodiment, a brushless car wash system for washing a vehicle comprises: a wash unit configured to spray water on an exterior of the vehicle to wash the vehicle; and a telescoping rail structure coupled to the wash unit at one end of the telescoping rail structure and configured to adjust a height of the wash unit by expanding or retracting a plurality of rail stages included in the telescoping rail structure as the vehicle is moved, the telescoping rail structure tilted at a fixed angle away from a front of the vehicle, the fixed angle measured with respect to a reference that is perpendicular to ground. 
     In one embodiment, a brushless car wash system for washing a vehicle comprises: a frame structure; a width adjustment unit configured to adjust a width of the brushless car wash system according to a width of the vehicle, the width adjustment unit including a plurality of base assemblies that hang from the frame structure, the plurality of base assemblies configured to physically contact the vehicle to adjust the width of the brushless car wash system according to the width of the vehicle; and a wash unit mounted on the plurality of plurality of base assemblies, the wash unit configured to spray water on a plurality of side surfaces of an exterior of the vehicle to wash the vehicle while the brushless car wash system is at the adjusted width. 
     In one embodiment, a brushless car wash system for washing a vehicle comprises: a width adjustment unit configured to adjust a width of the brushless car wash system according to a width of the vehicle, the width adjustment unit including a plurality of base assemblies that float off a ground surface and are configured to physically contact the vehicle to adjust the width of the brushless car wash system according to the width of the vehicle; and a wash unit mounted on the plurality of plurality of base assemblies, the wash unit configured to spray water on a plurality of side surfaces of an exterior of the vehicle to wash the vehicle while the brushless car wash system is at the adjusted width. 
     In one embodiment, a brushless car wash system for washing a vehicle comprises: a frame structure; a width adjustment unit configured to adjust a width of the brushless car wash system according to a width of the vehicle, the width adjustment unit including a plurality of arms and a plurality of base assemblies that hang from the frame structure via the plurality of arms, wherein each of the plurality of arms includes at least one bend; and a wash unit mounted on the plurality of plurality of base assemblies, the wash unit configured to spray water on a plurality of side surfaces of an exterior of the vehicle to wash the vehicle while the brushless car wash system is at the adjusted width. 
     The features and advantages described in the specification are not all inclusive and, in particular, many additional features and advantages will be apparent to one of ordinary skill in the art in view of the drawings, specification, and claims. Moreover, it should be noted that the language used in the specification has been principally selected for readability and instructional purposes, and may not have been selected to delineate or circumscribe the inventive subject matter. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a high-level block diagram of the two-stage brushless car wash system according to one embodiment. 
         FIG.  2    is a method flow diagram illustrating the independently performed steps of the first wash stage and the second wash stage of the two-stage brushless car wash system according to one embodiment. 
         FIGS.  3 A,  3 B, and  3 C  respectively illustrate perspective, front, and side views, respectively, of the first wash stage of the two-stage brushless car wash system according to one embodiment. 
         FIG.  4    illustrates chemical arches included in the first wash stage of the two-stage brushless car wash system according to one embodiment. 
         FIGS.  5 A and  5 B  illustrate an optical sensor included in the first wash stage of the two-stage brushless car wash system and sensing data of a vehicle according to one embodiment. 
         FIGS.  6 A- 6 H  illustrate operation of the first wash stage of the two-stage brushless car wash system according to one embodiment. 
         FIG.  7    illustrates operation of the first wash stage of the two-stage brushless car wash system to wash the rear surface of a vehicle according to one embodiment. 
         FIGS.  8 A- 8 D  show the retraction operation of a telescoping unit of the first wash stage according to one embodiment. 
         FIG.  8 E  illustrates a plan view of the telescoping unit according to one embodiment. 
         FIG.  8 F  illustrates a perspective view of the telescoping unit in the expanded state according to one embodiment. 
         FIGS.  9 A- 9 D  illustrate detailed views of components of the telescoping unit of the first wash stage according to one embodiment. 
         FIGS.  10 A to  10 E  illustrates detailed views of the shock reducing units of the telescoping unit of the first wash stage according to one embodiment. 
         FIG.  11    illustrates a detailed view of a mechanism for collapsing and expanding the telescoping unit of the first wash stage according to one embodiment. 
         FIG.  12 A to  12 C  illustrate detailed views of the drum and wire for collapsing and expanding the telescoping unit of the first wash stage according to one embodiment. 
         FIGS.  13 A- 13 D  illustrate various views of a wash unit of the first wash stage according to one embodiment. 
         FIG.  14    illustrates a wash unit of the first wash stage according to another embodiment. 
         FIGS.  15 A and  15 B  illustrate various views of a safety device of the first wash stage according to one embodiment. 
         FIGS.  16 A- 16 C  illustrate a reset apparatus of the first wash stage in response to a collision between the first wash stage and the vehicle according to one embodiment. 
         FIG.  17    illustrates a detailed view of the second wash stage of the two-stage brushless car wash system according to a first embodiment. 
         FIGS.  18 A- 18 D  illustrate operation of the second wash stage according to the first embodiment. 
         FIG.  19    illustrates dual bend arms of the second wash stage according to one embodiment. 
         FIGS.  20 A- 20 B  illustrate the center of gravity of the dual bend arms of the second wash stage according to one embodiment 
         FIGS.  20 C- 20 D  illustrate weights applied to the dual bend arms to change the center of gravity of the dual bend arms according to one embodiment. 
         FIG.  21    illustrates single bend arms of the second wash stage according to one embodiment. 
         FIG.  22 A  illustrate a path of motion of components of the second wash stage according to one embodiment. 
         FIG.  22 B  illustrates force vectors that cause the second wash stage to move in the path shown in  FIG.  22 A  according to one embodiment. 
         FIGS.  23 A,  23 B, and  23 C  illustrate detailed views of base assemblies of the second wash stage according to the first embodiment. 
         FIGS.  24 A to  24 B  illustrate plan views of the base assemblies according to the first embodiment. 
         FIG.  25    illustrates a plan view of the second wash stage according to one embodiment. 
         FIGS.  26 A and  26 B  illustrate nozzle assemblies of the second wash stage according to one embodiment. 
         FIG.  27 A  illustrates a detailed view of a collision prevention unit of the second wash stage according to one embodiment. 
         FIGS.  27 B to  27 C  illustrate operation of the collision prevention unit according to one embodiment. 
         FIG.  28    illustrates a detailed view of the second wash stage of the two-stage brushless car wash system according to a second embodiment. 
         FIGS.  29 A- 29 C  illustrate operation of the second wash stage according to the second embodiment. 
         FIGS.  30 A and  30 B  illustrate detailed views of base assemblies of the second wash stage according to the second embodiment. 
         FIGS.  31 A and  31 B  illustrates plan views of the base assemblies of the second wash stage according to the second embodiment. 
         FIG.  32    is a detailed view of the controller of the two-stage brushless car wash system according to one embodiment. 
         FIG.  33    is system diagram of a controller, according to one embodiment. 
     
    
    
     The figures depict embodiments of the present invention for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the invention described herein. 
     DETAILED DESCRIPTION 
       FIG.  1    is a high-level block diagram of the two-stage brushless car wash system  100  (hereinafter “car wash system  100 ”) according to one embodiment. The car wash system  100  is a tunnel-based car wash system that washes an exterior of a vehicle  101  in multiple, separate stages, in one example. The car wash system  100  includes a first wash stage  103 , a second wash stage  105 , a conveyer  107 , a controller  109 , and a water supply system  109  in one embodiment. The first wash stage  103  washes the upper (e.g., top) surfaces of the vehicle  101  whereas the second wash stage  105  washes the side surfaces of the vehicle  101  in one embodiment. The first wash stage  103  and the second wash stage  105  are physically separated and independently controlled by the controller  109  to wash the exterior of the vehicle  101 . 
       FIG.  2    is a method flow diagram illustrating the independently performed steps of the first wash stage  103  and the second wash stage  105  of the car wash system  100  to wash vehicle  101  according to one embodiment. The car wash system  100  receives  201  the vehicle  101  for washing. In one embodiment, the vehicle  101  is received when the vehicle  101  is driven onto the conveyer  107  included in the car wash system  100 . The conveyor  107  transports the vehicle  101  along the car wash system  100  at a predetermined speed such that the vehicle  101  passes through the first wash stage  103  followed by the second wash stage  105  to wash the exterior surfaces of the vehicle  101 . In one embodiment, the conveyor  107  transports the vehicle  101  through the car wash system  100  at a speed of 200 to 380 mm/s (7.8 to 14.9 inch/s) resulting in roughly 120-180 cars washed per hour. The conveyor  107  may transport the vehicle  101  at other speeds in different examples. 
     The car wash system  100  washes  202  upper surfaces of the vehicle  101  such as the front surface, top surface, and rear surface of the vehicle  101  using the first wash stage  103 . In one embodiment, examples of the front surface of the vehicle  101  include the front bumper, examples of the top surface of the vehicle  101  include the hood, front windshield, roof, rear windshield, a truck bed, and top portion of the rear decklid of the vehicle  101 , and examples of the rear surface of the vehicle  101  include the rear portion of the rear decklid and the rear bumper. 
     As will be described in further detail below, the first wash stage  103  is brushless. That is, the first wash stage  103  includes a wash unit (e.g., nozzles) that cleans the upper surfaces of the vehicle  101  without the use of brushes. The first wash stage  103  does not clean the side surfaces of the vehicle  101  as the second wash stage  105  washes the side surfaces of the vehicle  101  as will be further described below. 
     To wash the upper surfaces of the vehicle  101 , the first wash stage  103  determines  205  the contour profile of the vehicle  201 . The contour profile of the vehicle  101  describes various height points of the vehicle  101  along the length of the vehicle  101  according to one embodiment. The height points of the vehicle  101  included in the contour profile collectively describe the vertical shape of the front, top, and rear surface of the vehicle  101 . 
     The first wash stage  103  applies  207  chemical to the vehicle  101 . The first wash stage  103  applies the chemical to upper surfaces of the vehicle  101 . In one embodiment, the first wash stage  103  may also apply chemical to the side surfaces of the vehicle  101 . The chemical applied to upper surfaces of the vehicle  101  are used by the front wash stage  103  to wash the upper surfaces of the vehicle  101 . The chemical applied to the side surfaces may be used by the second wash stage  105  to wash the side surfaces of the vehicle  101 . The chemical may include for example soap or any other type of chemicals used during a car wash. In one embodiment, the first wash stage  103  may apply different soaps each with a different pH level to the vehicle  101 . 
     After the chemical is applied to the vehicle  101 , the first wash stage  103  activates  209  the wash unit of the first wash stage  103  to begin cleaning the vehicle  101  with water. The water sprayed by the wash unit of the first wash stage  103  is used to clean the upper surfaces of the vehicle  101 . As the vehicle  101  is moved along the first wash stage  103  by the conveyor  107 , the first wash stage  101  adjusts  211  the height of the wash unit according to the vertical contour profile of the vehicle  101  as the upper surfaces of the vehicle  101  are washed. Thus, the wash unit moves in accordance with the contour of the vehicle  101  to improve cleaning performance of the first wash stage  103  since the wash unit stays within a constant proximity to the upper surfaces of the vehicle (e.g., within a distance range). 
     As will be described in further detail below, adjusting the height of the wash unit of the first wash stage  103  allows the wash unit to maintain a predetermined distance range (e.g., the constant proximity) from the upper surfaces of the vehicle  101  to better clean the vehicle  101 . By maintaining the predetermined distance range between the wash unit and the upper surfaces of the vehicle  101 , the first wash stage  103  is capable of removing more dirt, grime, and/or road film from the upper surfaces of the vehicle  101  while reducing the amount of water used during the wash process compared to conventional brushless tunnel car wash systems. Also, damage to the paint of the vehicle  101  is at the very least reduced, since the first wash stage  103  is brushless. 
     After the first wash stage  103  has completed washing the upper surfaces of the vehicle  101 , the vehicle  101  exits the first wash stage  103  and the conveyer  107  transports the vehicle  101  to the second wash stage  105 . As mentioned previously, the second wash stage  105  washes  203  the side surfaces of the vehicle  101  independently from the first wash stage  103  after the first wash stage  103  is completed. Examples of the side surfaces of the vehicle include the front and rear fenders, the doors, side mirror, driver and/or passenger windows, wheels, and the sides of the front and rear bumpers. 
     In one embodiment, to wash the side surfaces of the vehicle  101  during the second wash stage  105 , the width of the second wash stage  213  is adjusted  213  based on the width of the vehicle  101 . After the width of the second wash stage  213  is adjusted, the wash unit of the second wash stage is activated  215  to wash the side surfaces of the vehicle  101 . Adjusting the width of the second wash stage  105  allows for the wash unit of the second wash stage  105  to maintain a predetermined distance range from the side surfaces of the vehicle  101  to better clean the side surfaces of the vehicle  101 . Thus, the wash unit of the second wash stage  105  is able to account for the contour of the side surface of the vehicle  101 . By maintaining the predetermined distance range between the wash unit and the side surfaces of the vehicle  101 , the second wash stage  105  is capable of removing more dirt, grime, and/or road film from the side surfaces of the vehicle  101  while reducing the amount of water used during the wash process compared to conventional brushless tunnel car wash systems. 
     In one embodiment, the water supply system  109  supplies water to the first wash stage  103  and the second wash stage  105 . The water supplied by the water supply system  109  is pressurized at a predetermined pressure and is also heated to a predetermined temperature. In one embodiment, the water supply system  109  includes at least a boiler for heating and maintaining the water supplied to the first wash stage  103  and the second wash stage  105  at the predetermined temperature. The water supply system  109  may also include a pressure pump system for supplying the water to the first wash stage  103  and the second wash stage  105  at the predetermined pressure (e.g., 1000 PSI). The water supply system  109  may be housed in a machine room separate from the first wash stage  103  and second wash stage  105  or is in the same room as the first wash stage  103  and the second wash stage  105 . 
     Overview of First Wash Stage  103   
     Referring to  FIGS.  3 A,  3 B, and  3 C , perspective, front, and side views, respectively, of the first wash stage  103  of the car wash system  100  are shown according to one embodiment. The first wash stage  103  includes an optical sensor  301 , a frame  302 , a water supply line  303 , a telescoping unit  304 , a motor  305 , a wash unit  306 , and a safety device  307  that are each described in further detail below. The first wash stage  103  may have additional or fewer components than described herein in other examples. 
     In one embodiment, the optical sensor  301  is used in conjunction with the controller  109  to identify the contour profile of the vehicle  101 . As mentioned previously, the contour profile of the vehicle  101  includes a plurality of height points of the vehicle  101  that are measured along the length of the vehicle  101 . Each height point represents a height of a part of the vehicle. The height points included in the contour profile of the vehicle  101  are arranged in an order of sensing from the optical sensor  301  to correctly describe the shape of the front, top, and rear surfaces of the vehicle  101 . 
     In one embodiment, the optical sensor  301  may be positioned normal to ground (e.g., straight up ground). Alternatively, the optical sensor  301  may be tilted at a fixed angle Θ toward the front of the vehicle  101  where the angle Θ is measured from a reference  309  that is normal to the ground. For example, the optical sensor  301  may be positioned at a predetermined angle Θ range between 13-17 degrees from the reference  309 . The optical sensor  301  may be angled in order to reduce the measured distance between the adjacent height points sensed by the optical sensor  103 , as will be further described below. 
     In one embodiment, the optical sensor  301  is a light curtain sensor. The light curtain sensor includes a plurality of photoelectric beams. Each photoelectric beam emits light shown as an individual line of light  308  in  FIG.  3 A . Each individual line of light  308  represents a particular height. As the vehicle  101  passes through the light curtain sensor, the array of photoelectric beams sense intrusions into the plane of detection of the light curtain sensor and the various height points of the vehicle  101  are sensed based on which of the photoelectric beams are intruded. Based on the sensed points of intrusions communicated back to the controller  109 , the controller  109  may determine the various height points of the front, top, and rear surfaces of the vehicle  101  to generate the contour profile of the vehicle  101 . 
     In another embodiment, the optical sensor  301  is a three-dimension (3D) sensor. The 3D sensor is used to measure the dimensions of the vehicle  101  in three dimensions (e.g., x, y, and z dimensions) to generate the contour profile of the vehicle  101 . The measured dimensions of the vehicle  101  include the heights of the upper surfaces of the vehicle  101 . 
     In one embodiment, the 3D sensor includes at least two sensors (e.g., projected-light sensors) positioned towards the front of the vehicle  101 . One sensor may be positioned at a driver side of the vehicle  101  and a second sensor may be positioned at a passenger side of the vehicle  101 . As the vehicle  101  passes the sensors, each sensor illuminates the vehicle  101  with light (e.g., a laser) and measures the backscattered light to determine the dimensions (e.g., heights and/or widths) of the vehicle  101 . 
     The frame  302  is a structure used to support the other components of the first wash stage such as the water supply line  303 , the telescoping unit  304 , the motor  305 , the wash unit  306 , and a safety device  307 . The frame  302  includes a plurality of frame rails  302 A- 302 D that collectively form the frame  302 D and mechanically support the water supply line  303 , telescoping unit  304 , and motor  305 . The frame  302  may be made of metal such as steel or aluminum or other metals. 
     In one embodiment, the frame  302  has a height greater than 90 inches and a width of 134 inches in one embodiment to accommodate vehicles  101  with a maximum height of 90 inches and a maximum width of 90 inches. However, the frame  302  may have different dimensions depending on the size of the vehicles being washed. 
     The telescoping unit  304  may be considered a height adjustment unit since the telescoping unit  304  adjusts a height of the wash unit  306 . The telescoping unit  304  is a telescoping rail, in one embodiment. The telescoping unit  304  is configured to retract or expand in accordance with the contour profile of the vehicle  101 , so as to maintain the predetermined distance range between the wash unit  306  and the upper surfaces of the vehicle  101  during the first wash stage  103 . As shown in  FIG.  3 C , a portion  311  of the telescoping unit  304  is mounted to the frame  302  using a mounting plate  313 . As shown in  FIGS.  3 A and  3 C , the mounting plate  313  is mounted to frame rail  302 D. The mounting plate  313  may be mounted to the frame rail  302 D using fasteners such as nuts and bolts, or the mounting plate  313  may be welded to the frame rail  302 D. 
     The wash unit  306  may be a water manifold with a plurality of nozzles attached to the water manifold as will be further described in detail below. The wash unit  306  is used to spray pressurized water on the upper surfaces of the vehicle  101  to clean the vehicle  101 . The wash unit  306  is attached to ends  315 A,  315 B of the telescoping unit  304  as shown in  FIG.  3 B . As mentioned above, the wash unit  306  is maintained within a predetermined distance range between the upper surfaces of the vehicle  101  during the first wash stage to enhance wash performance. 
     The water supply lines  303  supply water provided by the water supply system  109  to the wash unit  306 . The water supply lines  303  may include water supply line  303 A and water supply line  303 B that are each disposed at one side of the telescoping unit  304  as shown in  FIG.  3 B . An end of each water supply line is attached to the wash unit  306 . For example, the end  316 A of water supply line  303 A is attached to the wash unit  306  and the end  316 B of water supply line  303 B is attached to the wash unit  306 . 
     The motor  305  is configured to spin to retract or expand the telescoping unit  304  while the vehicle  101  is being washed during the first wash stage  103 . The motor  305  is controlled by the controller  109  to retract or expand the telescoping unit  304  in accordance with the contour profile of the vehicle  101  so that the wash unit  306  is maintained at the predetermined distance range of the surface of the front, top, and rear surfaces of the vehicle  101 . In one embodiment, the motor  305  is attached to the upper most end  317  of the telescoping unit  304 . 
     The safety device  307  is configured to reduce damage to the vehicle  101  upon impact between the vehicle  101  and the safety device  307 . The safety device  307  includes shock absorbent material that absorbs shock so as to reduce damage to the vehicle  101  upon impact. Impact may occur if the telescoping unit  304  is not properly retracted in accordance with the contour profile of the vehicle  101 . 
     In one embodiment, the safety device  307  includes a plurality of safety devices  307 A and  307 B. As will be further described below, the plurality of safety devices are attached to the wash unit  306  such that each safety device surrounds a portion of the wash unit  306 . Safety device  307 A is positioned on the wash unit  306  such that it is at one side of the water supply line  303 A (e.g., left of the water supply line  303 A) and safety device  307 B is positioned on the wash unit  306  such that it is to another side of the water supply line  303 B (e.g., right of the water supply line  303 B). Although the safety device  307  shown herein includes two safety devices, any number of safety devices may be used. 
     Referring to  FIG.  4   , the first wash stage  103  may also include a plurality of chemical arches  401 . Generally, chemical arches  401  are structures that spray chemicals on the vehicle  101  during the wash process of the car wash system  100 . The chemicals include soap for example. 
     In one embodiment, the chemical arches  401  apply detergent to the upper surfaces of the vehicle  101 . The chemical arches  401  may also apply detergent to the side surfaces of the vehicle  101 . In one embodiment, each of the chemical arches  401 A and  401 B simultaneously spray the upper surfaces and the side surfaces of the vehicle  101  with detergent. The detergent applied to the upper surfaces of the vehicle  101  are used by the first wash stage  103  to wash the upper surfaces vehicle. In some embodiments, the detergent applied to the side surfaces may be used by the second wash stage  105  to wash the side surfaces of the vehicle  101 . In some embodiments, the detergent sprayed by the first chemical arch  401 A and the detergent sprayed by the second chemical arch  401 B are the same. Alternatively, the detergent sprayed by the first chemical arch  401 A is different from the detergent sprayed by the second chemical arch  401 B. An example of detergent is soap. 
     In one embodiment, chemical arch  401 A applies detergent with a first pH level to the vehicle  101  and chemical arch  401 B applies detergent with a second pH level to the vehicle  101 . The first and second pH levels are different from each other in one embodiment, but may be the same in other embodiments. 
     As shown in  FIG.  4   , the chemical arches  401  are positioned between the optical sensor  301  and the frame  302 . In one embodiment, the first chemical arch  401 A is positioned at least 157 inches to a maximum of 236 inches from the optical sensor  301 . In one embodiment, the distance between chemical arch  401 A and  401 B may be different from car wash to car wash. The distance between the chemical arches  401  may be based upon different actors such as dwell time between the different detergents applied by the chemical arches  401  and speed of the conveyor  107 , for example. In one embodiment, a different optical sensor from the optical sensor  301  may be used to activate the chemical arches  401 . 
     Optical Sensor  301   
       FIG.  5 A  illustrates a plurality of height points of the vehicle  101  according to one embodiment. As mentioned previously, the optical sensor  301  is used in conduction with the controller  109  to identify the contour profile of the vehicle  101  that describes the different height points of the vehicle  101 . In  FIG.  5 A , each dot  501  represents a height point along one of the upper surfaces of the vehicle  101 . For example, dot  501 A represents a height of a front surface of the vehicle (e.g., on the front bumper), dots  501 B and  501 D represent adjacent heights on the top surface of the vehicle  101  (e.g., on the hood), and dot  501 C represents a height on the rear surface of the vehicle  101  (e.g., on the rear bumper). The optical sensor  301  and controller  109  may determine multiple height points along each of the front, top, and rear surfaces of the vehicle.  FIG.  5 B  illustrates a graph  503  of the height points of the vehicle  101  sensed over time by the optical sensor  301  and controller  109 . The different height points collectively represent the contour  505  of the upper surfaces of the vehicle  101 , as shown in  FIG.  5 B . 
     As mentioned previously, in the embodiment where the optical sensor  301  is a light curtain sensor, the light curtain sensor may be positioned at an angle Θ toward the front of the vehicle  101  where the angle Θ is measured from a reference  309  that is normal to the ground as shown in  FIG.  5 A . The optical sensor  301  may be positioned at an angle range between 13-17 degrees from the reference  309  in order to reduce the measured distance between adjacent vehicle height points (e.g., heights  501 B and  501 D) measured using the optical sensor  301 . In one embodiment, the angle range of the optical sensor  301  is based on factors including speed of the vehicle  101  though the car wash system  100  and speed in which the telescoping unit  304  can be expanded/retracted. In one embodiment, positioning the optical sensor  301  within the angle range of 13-17 degrees from the reference  309  is based on the assumption that the moving speed of the vehicle is in a speed range of 200 mm/s to 380 mm/s (e.g., 7.8 inches/s to 14.9 inches/s) and that the telescoping unit  304  can retract/expand at a maximum speed of 1 m/s. 
     Generally, the performance of the optical sensor  304  in measuring the height points of the vehicle  101  varies depending on the angle of the optical sensor  301  as shown in Table 1 below. The performance of the optical sensor  301  describes the distance between adjacent height points. In one embodiment, the optimum performance of the first wash stage  103  occurs when the distance measured between adjacent height points by the optical sensor  301  is 1 meter or less, given that the telescoping unit  304  may expand/retract at a maximum speed of 1 m/s. 
     
       
         
           
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                 Sensor Angle 
                 0-12 degrees 
                 13-17 degrees 
                 18-20 degrees 
               
               
                   
               
             
            
               
                 Vehicle Moving 
                 200 mm/s to 380 mm/s 
                 200 mm/s to 380 mm/s 
                 200 mm/s to 380 mm/s 
               
               
                 Speed 
                 (e.g., 7.8 in/s to 14.9 
                 (e.g., 7.8 in/s to 14.9 
                 (e.g., 7.8 in/s to 14.9 
               
               
                   
                 in/s) 
                 in/s) 
                 in/s) 
               
               
                 Performance 
                 Distance between 
                 Distance between 
                 Distance between 
               
               
                   
                 adjacent height points 
                 adjacent height points 
                 adjacent height points 
               
               
                   
                 increases compared to 
                 within 1 m. 
                 decreases compared to 
               
               
                   
                 angle range 13-17 
                 Advantageous for 
                 angle range 13-17 
               
               
                   
                 degrees. Advantageous 
                 measuring height of 
                 degrees. Advantageous 
               
               
                   
                 for measuring height of 
                 both front and rear 
                 for measuring height of 
               
               
                   
                 front of vehicle, but 
                 surfaces of vehicle 
                 rear of vehicle, but 
               
               
                   
                 disadvantageous for 
                   
                 disadvantageous for 
               
               
                   
                 measuring height of 
                   
                 measuring height of 
               
               
                   
                 rear of vehicle. 
                   
                 front of vehicle. 
               
               
                   
               
            
           
         
       
     
     Generally, the distance between adjacent height points measured using the optical sensor  301  vary depending on the angle of the optical sensor  301 . For example, positioning the optical sensor  301  at an angle range of 13 to 17 degrees allows for adjacent height points measured using the optical sensor  301  to be within 1 meter of each other and can measure front and rear heights above 1 meter. Thus, the angle range of 13 to 17 degrees for the optical sensor  301  is optimal given that the maximum speed of the telescoping unit  304  is 1 m/s. 
     In contrast, positioning the optical sensor at an angle less than the angle range of 13 to 17 degrees such as between 0 to 12 degrees results in the distance between adjacent height points on the front, top, and rear surfaces of the vehicle  101  increasing compared to the distance between adjacent height points measured when the angle of the optical sensor  301  is in the angle range of 13-17 degrees. Furthermore, using an angle of 0 to 12 degrees is advantageous for recognizing the height of the front of the vehicle  101  as the optical sensor  301  can measure heights above 600 mm (23.6 in), but disadvantageous for measuring heights of the rear surface of the vehicle  101 . 
     Also, positioning the optical sensor at an angle greater than the angle range of 13 to 17 degrees such as between 18 to 20 degrees results in the distance between adjacent height points on the front, top, and rear surfaces of the vehicle  101  decreasing compared to the distance between adjacent height points measured when the angle of the optical sensor  301  is in the angle range of 13-17 degrees. However, using an angle of 18 to 20 degrees is advantageous for recognizing the height of the rear of the vehicle  101  as the optical sensor  301  can measure heights above 800 mm (31.5 in), but is disadvantageous for measuring heights of the front of the vehicle  101 . Thus, using an angle range of 13 to 17 degrees for the optical sensor  301  results in the best performance for measuring the heights of the front and rear surfaces of the vehicle  101  while reducing the distance between adjacent heights measured using the optical sensor  301 . 
     Telescoping Unit Operation 
       FIGS.  6 A- 6 H  illustrate operation of the first wash stage  103  of the wash system  100  to wash front, top, and rear surfaces of a vehicle  101  according to one embodiment. In particular,  FIGS.  6 A- 6 H  illustrate how the height of the wash unit  306  is adjusted in accordance with the vertical contour profile of the vehicle  101  by retracting or expanding the telescoping unit  304 . Due to the height of the wash unit  306  being adjusted as the vehicle is moved under the wash unit  306 , the wash unit  306  is kept within a predetermined distance range from the upper surfaces of the vehicle  101  to increase cleaning efficiency. In one embodiment, the wash unit  306  is kept within the predetermined distance range of 10 to 15 inches from the upper surfaces of the vehicle  100  during the first wash stage  103  as the vehicle is moved under the wash unit  306 . By keeping the wash unit  306  within the predetermined distance range, the water temperature of the water output by the wash unit  306  may be in a predetermined temperature range (e.g., 110 to 140 degrees F.) when the water contacts the upper surfaces of the vehicle  101  thereby resulting in enhanced wash performance in one embodiment. 
       FIG.  6 A  illustrates the initial position of the wash unit  306 . The motor  304  extends the telescoping unit  304  so as to position the wash unit  306  at a position associated with a first height included in the contour profile for the vehicle  101  to begin washing the front surface  601  of the vehicle  101 . In  FIG.  6 B , the motor  305  retracts the telescoping unit  304  in accordance with the contour profile of the vehicle  101  to raise the wash unit  306  as the wash unit continues to spray water to clean the front surface  601  of the vehicle  101 . In  FIG.  6 C , the motor  305  further retracts the telescoping unit  304  thereby raising the wash unit  306  to wash the top surface  603  (e.g., the hood) of the vehicle  101 . In  FIG.  6 D , the motor  305  again retracts the telescoping unit  304  further thereby raising the wash unit  306  to wash the top surface (e.g., the roof)  603  of the vehicle  101 , and the motor  305  maintains the height of the telescoping unit  304  across the roof of the vehicle  101  as shown in  FIG.  6 E . In  FIG.  6 F , the motor  305  expands the telescoping unit  304  thereby lowering the wash unit  306  to wash the top surface (e.g., the bed)  603  of the vehicle, and the motor  305  maintains the height of the telescoping unit  304  across the bed of the vehicle as shown in  FIG.  6 F . The motor  305  further expands the telescoping unit  304  in  FIGS.  6 G- 6 H  to wash the rear surfaces  605  of the vehicle  601  as described with respect to  FIG.  7   . 
       FIG.  7    illustrates a detailed view of the first wash stage  103  as the rear surface  605  of the vehicle  101  is washed. As shown in  FIG.  7   , the telescoping unit  304  is positioned at an angle within a predetermined angle range a with respect to reference line  701  that is positioned normal to ground. In one embodiment, the telescoping unit  304  is at the fixed angle within the angle range a while the telescoping unit  304  is not in contact with the vehicle  101 . That is, the telescoping unit  304  remains at the angle during the duration of the first wash stage  103  unless there is contact between the telescoping unit  304  and the vehicle  101 . 
     As shown in  FIG.  7   , the telescoping unit  304  is angled toward the rear surface  605  of the vehicle  101  as the vehicle moves away from the first wash stage  103 . By angling the telescoping unit  304  toward the rear surface  605  at the angle α while washing the rear of the vehicle  101 , the wash unit  306  is able to stay within a predetermined distance range from the rear surface  605  of the vehicle  101  for a duration of time as the vehicle  101  moves farther away from the first wash stage  103 . If the telescoping unit  304  were not angled toward the rear of the vehicle  101  while washing the rear surface of the vehicle  101 , the telescoping unit  304  would move only in the vertical direction (e.g., not in horizontal direction) and the wash unit  306  would be unable to maintain the predetermined distance range to the rear surface of the vehicle  101  as the vehicle  101  moves away from the first wash stage  103 . This results in insufficient cleaning of the rear surface of the vehicle  101 . 
     However, since the telescoping unit  304  is angled towards the rear surface of the vehicle  101  at the angle α while washing the rear surface, the wash unit  306  is able to stay within the predetermined distance range from the rear surface  605  as the vehicle  101  moves away for a duration of time until the vehicle  101  moves farther away from the first wash stage  103 . While washing the rear surface of the vehicle  101 , the angled telescoping unit  304  moves in both the horizontal and vertical directions as the telescoping unit  304  is expanded due to the telescoping unit  304  being tilted at the angle α. Since the telescoping unit  304  moves in both the horizontal and vertical direction as the telescoping unit  304  expands, the telescoping unit  304  allows for the wash unit  304  to stay within the predetermined distance range from the rear of the vehicle  101  for a duration of time as the vehicle  101  moves away from the first wash stage  101 . That is, the first wash stage  103  follows a contour of the rear surface of the vehicle  101  as the vehicle  101  is moving away from the first wash stage  103 . Since the first wash stage  103  is capable of following the contour of the rear surface of the vehicle  101  as the vehicle moves away from the first wash stage  103 , the rear surface of the vehicle  101  is more thoroughly cleaned compared to if the telescoping unit  304  were to only move in the vertical direction while washing the rear surface of the vehicle  101 . 
     The telescoping unit  304  may be positioned at an angle within an angle range that matches the angle range of the optical sensor  301  in one embodiment. That is, the telescoping unit  304  may be tilted at an angle within an angle range that is the same as the angle range of the optical sensor  301 . For example, the telescoping unit  304  is positioned at an angle between the angle range of 13 to 17 degrees from the reference  701  and the angle range of the optical sensor  301  is also 13 to 17 degrees. In one embodiment, the telescoping unit  304  is tilted at the same angle as the optical sensor  301 . For example, both the telescoping unit  304  and the optical sensor  301  are tilted at an angle of 15 degrees. However, in other embodiments the telescoping unit  304  is positioned at an angle that is different from the angle of the optical sensor  301 . For example, the telescoping unit  304  is positioned at an angle between the angle range of 13 to 17 degrees from the reference line  701  whereas the optical sensor  301  is not tilted (e.g., positioned normal to ground). 
     In one embodiment, the angle range of the telescoping unit  304  is set based on various factors including the predetermined distance range from the wash unit  306  to the upper surfaces of the vehicle  301 , the initial position (e.g., initial height) of the wash unit  306 , and the size of the safety device  307 . In one embodiment, positioning the telescoping unit  304  within the angle range of 13-17 degrees from the reference  701  is based on the assumption that the wash unit  306  is kept within the predetermined distance range of 10 to 15 inches from the upper surfaces of the vehicle  100 , that the wash unit  306 &#39;s initial position above ground level is in a range from 480 mm to 520 mm (e.g.,  18 . 8  in to 20.5 in), and the diameter of the safety device  307  is in a range of 280 mm to 320 mm (e.g.,  11  in to 12.6 in). 
     The performance of the telescoping unit  304  varies depending on the angle of the telescoping unit  304  as shown in Table 2 below. 
     
       
         
           
               
               
               
               
             
               
                 TABLE 2 
               
               
                   
               
               
                 Telescoping Unit 
                   
                   
                   
               
               
                 Angle 
                 0-12 degrees 
                 13-17 degrees 
                 18-20 degrees 
               
               
                   
               
             
            
               
                 Distance from 
                 250 mm to 300 mm 
                 250 mm to 300 mm 
                 250 mm to 300 mm 
               
               
                 Water Nozzle to 
                 (e.g., 9.8 in to 11.8 in) 
                 (e.g., 9.8 in to 11.8 in) 
                 (e.g., 9.8 in to 11.8 in) 
               
               
                 Vehicle Surface 
                   
                   
                   
               
               
                 Water Nozzle 
                 480 mm to 520 mm 
                 480 mm to 520 mm 
                 480 mm to 520 mm 
               
               
                 Initial Position 
                 (e.g., 18.8 in to 20.5 
                 (e.g., 18.8 in to 20.5 in) 
                 (e.g., 18.8 in to 20.5 in) 
               
               
                   
                 in) 
                   
                   
               
               
                 Safety Device 
                 280 mm to 320 mm 
                 280 mm to 320 mm 
                 280 mm to 320 mm 
               
               
                 Diameter 
                 (e.g., 11 in to 12.6 in) 
                 (e.g., 11 in to 12.6 in) 
                 (e.g., 11 in to 12.6 in) 
               
               
                 Nozzle Distance 
                 Excellent 
                 Good 
                 Poor 
               
               
                 Performance 
                   
                   
                   
               
               
                 Collision 
                 Good 
                 Excellent 
                 Poor 
               
               
                 Performance 
                   
                   
                   
               
               
                 Front Cleaning 
                 Excellent 
                 Good 
                 Poor 
               
               
                 Performance 
                   
                   
                   
               
               
                 Rear Cleaning 
                 Poor 
                 Good 
                 Excellent 
               
               
                 Performance 
               
               
                   
               
            
           
         
       
     
     Table 2 above describes the performance of the telescoping unit  304  when positioned at the different angle ranges of 1) 0 to 12 degrees 2) 13 to 17 degrees and 3) 18 to 20 degrees. The performance of the telescoping unit  304  is described with respect to different types of performance criteria such as nozzle distance performance, collision performance, front cleaning performance, and rear cleaning performance. For each type of performance criteria, each angle range is assigned a score of “excellent,” “good,” or “poor” as will be further described below. 
     In one embodiment, nozzle distance performance describes how well ends of nozzles of the wash unit  306  are able to stay within the predetermined water nozzle distance range to the upper surfaces of the vehicle  101  (e.g., 250 mm to 300 mm) when the telescoping unit  304  is positioned at a given angle range. Note that the predetermined water nozzle distance range of 250 mm to 300 mm (e.g., 9.8 to 11.8 inches) is the range used for testing the various telescoping unit  304  angles. However, in one embodiment the optimum water nozzle distance range between the wash unit  306  and the upper surface of the vehicle  101  for wash performance is 10 to 15 inches. 
     Generally, the nozzles of the wash unit  306  are positioned as close as possible to the upper surfaces of the vehicle  101  without contacting the vehicle. A score of “excellent” indicates that the wash unit  306  is maintained at the lower end of the predetermined water nozzle distance range (e.g., 250 mm) whereas as score of “good” indicates that the wash unit  306  is maintained at a distance corresponding to the center of the range (e.g., 275 mm) in one embodiment. A score of “poor” indicates that the wash unit  306  is at a distance from the upper surfaces of the vehicle  101  that are outside of the predetermined water nozzle distance range. A nozzle distance performance score of “good” or “excellent” are considered acceptable performance whereas a score of “poor” is unacceptable performance in one embodiment. 
     As shown in Table 2, positioning the telescoping unit  304  at an angle range of 13-17 degrees resulted in “good” nozzle distance performance whereas positioning the telescoping unit  304  at the angle range of 0 to 12 degrees resulted in “excellent” nozzle distance performance. In contrast, positioning the telescoping unit  304  at the angle range of 18 to 20 degrees resulted in “poor” nozzle distance performance. 
     In one embodiment, collision performance describes the likelihood (e.g., risk) of collision between the telescoping unit  304  and the front, top, and rear surfaces of the vehicle  101 . With respect to collision performance, a score of “excellent” indicates that it is unlikely that an impact will occur between the telescoping unit  304  and the vehicle  101 , whereas a score of “good” indicates that there is a possibility of impact between the telescoping unit  304  and the vehicle  101 . In contrast, a score of “poor” indicates that a collision between the telescoping unit  304  and the vehicle  101  is likely to occur. A collision performance score of “good” or “excellent” are considered acceptable performance whereas a score of “poor” is unacceptable performance in one embodiment. 
     As shown in Table 2, positioning the telescoping unit  304  at an angle range of 13-17 degrees resulted in “excellent” collision performance indicating that a collision between the telescoping unit  304  and the vehicle  101  is unlikely to occur, whereas positioning the telescoping unit  304  at the angle range of 0 to 12 degrees resulted in “good” collision performance. Since the angle range of 0 to 12 degrees resulted in “good” collision performance, there is still a danger of contact between the telescoping unit  304  and the vehicle  101 . As shown in Table 2, positioning the telescoping unit  304  at the angle range of 18-20 degrees resulted in “poor” performance indicating that contact between the telescoping unit  304  and the vehicle  101  is likely. 
     In one embodiment, front cleaning performance describes the front cleaning efficiency of the front surface of the vehicle  101  using the first wash stage  103 . Front cleaning efficiency relates to how much of the front surface of the vehicle is washed. With respect to front cleaning performance, a score of “excellent” indicates that almost all of the front surface of the vehicle is washed whereas a score of “good” indicates a majority of the front surface of the vehicle  101  is washed. In contrast, a score of “poor” indicates that the majority of the front surface of the vehicle is unwashed after washing is performed by the first wash stage  101 . A front performance score of “good” or “excellent” are considered acceptable performance whereas a score of “poor” is unacceptable performance in one embodiment. 
     As shown in Table 2, positioning the telescoping unit  304  at an angle range of 13-17 degrees resulted in “good” front cleaning performance in that the majority of the front surface of the vehicle  101  is cleaned. Similarly, positioning the telescoping unit  304  at an angle range of 0 to 12 degrees resulted in “excellent” front cleaning performance in that almost all of the front surface of the vehicle  101  is cleaned. As shown in Table 2, positioning the telescoping unit  304  at the angle range of 18-20 degrees resulted in “poor” performance indicating that the majority of the front surface of the vehicle  101  is unwashed after washing is performed by the first wash stage  101 . 
     In one embodiment, rear cleaning performance describes the rear cleaning efficiency of the rear surface of the vehicle  101  using the first wash stage  103 . Rear cleaning efficiency relates to how much of the rear surface of the vehicle is washed. With respect to rear cleaning performance, a score of “excellent” indicates that almost all of the rear surface of the vehicle is washed whereas a score of “good” indicates a majority of the rear surface of the vehicle  101  is washed. In contrast, a score of “poor” indicates that the majority of the rear surface of the vehicle is unwashed after washing is performed by the first wash stage  101 . A rear performance score of “good” or “excellent” are considered acceptable performance whereas a score of “poor” is unacceptable performance in one embodiment. 
     As shown in Table 2, positioning the telescoping unit  304  at the angle range of 13 to 17 degrees resulted in “good” cleaning performance in that the majority of the rear surface of the vehicle  101  is washed. Due to the angle range of 13 to 17 degrees of the telescoping unit  304 , the wash unit  306  is able to wash the majority of the rear surface of the vehicle  101  as the vehicle  101  moves away from the front wash stage  101 . In contrast, positioning the telescoping unit  304  at an angle range of 0-12 degrees resulted in “poor” rear cleaning performance in that the majority of the front surface of the vehicle  101  is unwashed. Due to the shallow angle of the telescoping unit  304  when positioned at the angle range of 0 to 12 degrees, the wash unit  306  cannot adequately clean the rear surface of the vehicle  101  as it moves away from the front wash stage  101  due the telescoping unit  304  moving in the vertical direction, but not the horizontal direction. Since the telescoping unit  304  moves mostly in the vertical direction, the wash unit  306  cannot stay within the predetermined distance range to the rear surface of the vehicle  101  as the vehicle  101  moves away from the first wash stage  103 . Lastly, positioning the telescoping unit  304  at an angle range of 18 to 20 degrees resulted in “excellent” rear cleaning performance in that the majority of the rear surface of the vehicle  101  is cleaned during the first wash stage  101 . Due to the large angle, the wash unit  306  is able wash almost all of the rear surface of the vehicle  101  as the vehicle  101  moves away from the first wash stage  101  since the telescoping unit  304  moves in both the horizontal and vertical direction as the telescoping unit  304  expands to wash the rear surface of the vehicle  101 . 
     As shown in Table 2, in general as the angle range of the telescoping unit  304  decreases, the likelihood of collision decreases while also reducing overall cleaning performance (e.g., front and rear cleaning performance). In contrast, as the angle range of the telescoping unit  304  increases, the overall cleaning efficiency (e.g., front and rear cleaning performance) increases, but at the expense of decreased collision performance. The angle range of 13 to 17 degrees for the telescoping unit  304  results in the best balance of the different types of performance criteria such as nozzle distance performance, collision performance, front cleaning performance, and rear cleaning performance. 
     Telescoping Unit  304   
       FIGS.  8 A- 8 D  illustrates a detailed view of stages of the telescoping unit  304  according to one embodiment. Note that there are states of the telescoping unit  304  that are in between the different states of the telescoping unit  304  shown in  FIGS.  8 A- 8 D . In one embodiment, the telescoping unit  304  includes a plurality of rail stages  801 A,  801 B,  801 C, and  801 D. Rail stage  801 A is the first rail stage, rail stage  801 B is the second rail stage, rail stage  801 C is the third rail stage, and rail stage  801 D is the fourth rail stage, for example. In one embodiment, the telescoping unit  304  is collapsible such that rail stages  801 B to  801 D can be collapsed to fit within rail stage  801 A as will be described. The rail stages  801  may be made of aluminum for example, but other materials may be used. 
       FIG.  8 A  illustrates the telescoping unit  304  in the fully expanded state. In the fully expanded state, each rail stage  801  is fully expanded such that it protrudes from its preceding rail stage as far as possible. In the fully expanded state, the telescoping unit  304  is at its longest possible length. In the fully expanded state of the telescoping unit  304 , rail stage  801 D is fully expanded from rail stage  801 C, rail stage  801 C is fully expanded from rail stage  801 B, and rail stage  801 B is fully expanded from rail stage  801 A. 
       FIG.  8 B  illustrates the telescoping unit  304  in a first intermediate state. In the first intermediate state, the last rail stage  801 D is collapsed within its preceding rail stage  801 C. In the first intermediate state, rail stage  801 D is housed within its preceding rail stage  801 C while rail stage  801 C and rail stage  801 B are fully expanded from their respective preceding rail stage. For example, rail stage  801 C is fully expanded from rail stage  801 B and rail stage  801 B is fully expanded from rail stage  801 A. 
       FIG.  8 C  illustrates the telescoping unit  304  in a second intermediate state. In the second intermediate state, the last rail stage  801 D is collapsed within its preceding rail stage  801 C and the third rail stage  801 C is collapsed within its preceding rail stage  801 B. In the second intermediate state, rail stage  801 C is housed within its preceding rail stage  801 B while rail stage  801 B is fully expanded from its respective preceding rail stage. For example, rail stage  801 B is fully expanded from rail stage  801 A. Since the last rail stage  801 D is collapsed within rail stage  801 C from the first intermediate stage, the last rail stage  801 D is also collapsed within rail stage  801 B while rail stage  801 C is collapsed within rail stage  801 B. 
       FIG.  8 D  illustrates the telescoping unit  304  in a fully collapsed state. In the fully collapsed state, the telescoping unit  304  is at its shortest possible length. As shown in  FIG.  8 D , in the fully collapsed state, the second rail stage  801 B is collapsed within its preceding rail stage  801 A (e.g., the first rail stage). Since rail stage  801 D and rail stage  801 C are both collapsed within rail stage  801 B in the second intermediate state, in the fully collapsed state, rail stages  801 D,  801 C, and  801 B are all housed within rail stage  801 A. 
       FIG.  8 E  illustrates a plan view of each of rail stages  801 A to  801 D according to one embodiment. As shown in  FIG.  8 E , each rail stage  801 A- 801 D includes a plurality of vertical sides  802  arranged along a first direction (e.g., Y direction) and a plurality of horizontal sides  803  arranged along a second direction (e.g., X direction). For example, the plurality of vertical sides  802  of each rail stage  801 A- 801 D include a vertical side  802 A and a vertical side  802 B opposite to the vertical side  802 A. Furthermore, the plurality of horizontal sides  803  of each rail stage  801 A- 801 D includes a horizontal side  803 A, horizontal side  803 B, and horizontal side  803 B spaced apart from each other, for example. 
     Each rail stage  801 A to  801 D includes an outer width A measured from the outer edge  805 A of the vertical side  802 A to the outer edge  805 B of vertical side  802 B of the respective rail stage  801 , and an inner width B measured from the inner edge  807 A of the vertical side  802 A to the inner edge  807 B of vertical side  802 B of the respective rail stage. As shown in Figure A, outer width A is greater than inner width B for each respective rail stage. 
     As shown in  FIG.  8 E , rail stage  801 A is the widest rail stage amongst all the rail stages given that rail stages  801 B to  801 D are configured to be housed within rail stage  801 A when the telescoping unit  304  is fully collapsed. That is, rail stage  801 A has the widest width A from amongst all rail stages  801 A to  801 D. Each subsequent rail stage following rail stage  801 A has a smaller width A than the rail stage that preceded it. For example, the outer width A of rail stage  801 B is less than the outer width A of rail stage  801 A, but is greater than the outer width A of rail stage  801 C and rail stage  801 D. The outer width A of rail stage  801 C is wider than outer width A of rail stage  801 D, but less than outer width A of rail stage  801 B and outer width A of rail stage  801 A. Lastly, outer width A of rail stage  801 D is less than outer width A of each of rail stages  801 A to  801 C. 
     In one embodiment, the outer width A of each rail stage except for rail stage  801 A is less than the inner width B of the rail stage immediately preceding the given rail stage. This allows for each rail stage except for rail stage  801 A to fit within the preceding rail stage when the telescoping unit  304  is collapsed. For example, the outer width A of rail stage  801 B is less than the inner width B of rail stage  801 A so that rail stage  801 B can fit within rail stage  801 A when the telescoping unit  304  is collapsed. Similarly, the outer width A of rail stage  801 C is less than the inner width B of rail stage  801 B so that rail stage  801 C can fit within rail stage  801 B when the telescoping unit  304  is collapsed. Lastly, the outer width A of rail stage  801 D is less than the inner width B of rail stage  801 C so that rail stage  801 D can fit within rail stage  801 C when the telescoping unit  304  is collapsed. 
       FIG.  8 F  illustrates a perspective view of the telescoping unit  304  according to one embodiment. In the fully expanded state, the telescoping unit  304  has a length C of 266 to 267 inches according to one embodiment. However, other lengths may be used for length C. The plurality of rail stages each have a length E (e.g., lengths E1, E2, E3, and E4). In one embodiment, rail stage  801 A is the longest rail stage with a length E1 of 89 inches. The remaining rail stages  801 B to  801 D have the same length E of 59 inches in one embodiment. In other embodiments, rail stages  801 B to  801 D have different lengths or the same length. 
     In one embodiment, each rail stage  801  has a thickness D. Rail stage  801 A has the largest thickness D amongst all rail stages  801  (e.g., thicknesses D1, D2, D3, and D3). The thickness D4 of each rail stage  801  subsequent to rail stage  801 A decreases such that the thickness D of a given rail stage is smaller than the preceding rail stage. For example, the thickness D2 of rail stage  801 B is smaller than thickness D1 of rail stage  801 A. Similarly, thickness D3 of rail stage  801 C is smaller than thickness D2 of rail stage  801 B. Lastly, thickness D4 of rail stage  801 D is smaller than thickness D3 of rail stage  801 C. 
     Referring to  FIGS.  9 A- 9 D , components of a rail stage  801  are shown according to one embodiment. The components of the rail stage  801  shown in  FIGS.  9 A- 9 D  are applicable to all of the rail stages  801 . In one embodiment, each vertical side  802  of each rail stage  801  except for rail stage  801 A includes a plurality of side rollers  902  disposed at one end (e.g., a top end) of the rail stage  801 .  FIG.  9 A  illustrates that the vertical side  802  of the rail stage  801 B includes a first side roller  902 A and second side roller  902 B. The side rollers  902  of each rail stage  801  are mounted on the outer edge  805  of the rail stage  801 . Referring specifically to  FIG.  9 C , each side roller  902  is mounted to the outer surface  805  of its respective rail stage  801  using fasteners such as a nut  909  and bolt  907 . 
     Thus, each rail stage  801  except for rail stage  801 A may include a total of four side rollers  901  with two side rollers mounted on the outer edge  805  of each vertical side  802  of the rail stage  801 . Having four side rollers  901  reduces the likelihood of the telescoping unit  304  of shaking while being collapsed or expanded. In one embodiment, the side rollers  902  are made of nylon, but other materials may be used. The side rollers  901  may have a diameter of 1 inch for example, but may have other diameters. 
     Furthermore, in one embodiment, both vertical sides  802 A and  802 B of each rail stage  801  includes a slot  901  that runs along the length of each vertical side  802  as shown in  FIG.  9 A . The side rollers  902  of a given rail stage are disposed within the slot  901  of the given rail stage&#39;s preceding rail stage. For example, assuming  FIG.  9 A  illustrates side rollers  902  of rail stage  801 B, the side rollers  902  are disposed within the slot  901  of rail stage  801 A. The combination of the side rollers  902  and the slots  901  on the rail stages restrict the direction of movement of the telescoping unit  304  in the direction of the slots  901  during the expansion or retraction of the telescoping unit  304 . 
     In one embodiment, each vertical side  802  of each rail stage  801  includes one or more cam rollers  903 . The cam rollers  903  of each rail stage  801  are disposed at least at one end of the rail stage  801 . The cam rollers  903  may be disposed at both the top and bottom ends of the rail stage  801  or may be disposed only at one end of the rail stage.  FIG.  9 A  illustrates that the vertical side  802  of the rail stage  801 A includes a cam roller  903  disposed at notch  905  formed in a corner of the bottom end of the vertical side  802  of the rail stage  801 A. The cam roller  903  protrudes from the notch  905  of the vertical side  802  of rail stage  801 A in a direction that is perpendicular to the outer surface  805  of the vertical side  802  of the rail stage  801 A. As shown in  FIG.  9 C , the cam roller  903  includes a threaded end  911  that screws into a hole formed within the notch  905  of the vertical side  902  in order to attach the cam roller  903  to the vertical side  802  of the rail stage  801 . The cam rollers  903  may have a diameter of 1.4 inch for example, but may have other diameters. The cam rollers  903  may be made of nylon, but other materials may be used. 
     In one embodiment, the cam roller  903  of each rail stage  801  is in contact with the outer surface  805  of the subsequent rail stage  801 . For example, cam roller  903  of rail stage  801 A is in contact with the outer surface  805  of rail stage  801 B as shown in  FIG.  9 A . The usage of the cam rollers  903  improves smooth movement of the telescoping unit  304  as the rail stages  801  are collapsed and expanded. The cam rollers  903  also assist in guiding each rail stage  801  in the proper direction as the rail stages  801  are collapsed and expanded. Given that the cam rollers  903  and side rollers  902  are made of nylon and the rail stages  801  are made of aluminum in one embodiment, wear on the rollers  902 ,  903  and the rail stages  801  is reduced thereby extending the time period between replacement of parts of the telescoping unit  304 . 
     As the telescoping unit  304  is transitioned between the collapsed and the expanded states, the different rail stages  801  of the telescoping unit  304  collide with one another. Collision between the different rail stages  801  creates shock which may damage the telescoping unit  304 . In one embodiment, each rail stage  801  of the telescoping unit  304  includes one or more shock reducing units  1000  as shown in  FIGS.  10 A to  10 E  to reduce damage to the different rail stages  801  as the telescoping unit  304  is expanded and contracted. 
     In one embodiment, the shock reducing unit  1000 B at the top of a rail stage  801  includes an impact reduction block  1001 . The impact reduction block  1001  is made of a shock absorbent material used to reduce impact such as urethane in one embodiment, but other materials may be used. The impact reduction block  1001  is mounted on a topmost horizontal side  803  of the rail stage  801  as shown in  FIG.  10 A . The impact reduction block  1001  is made of a material that is more elastic than the topmost horizontal side  803  of the rail stage. The impact reduction block  1001  may have a width that is the same width of the topmost horizontal side  803  of the rail stage  801  or may have a smaller width. 
     In one embodiment, the shock reducing unit  1000 A at the bottom of a rail stage  801  includes a shock absorber  1003  and a plurality of impact reduction pads  1005 . The shock absorber  1003  may be positioned between ends of the lowermost horizontal side  803  of the rail stage (e.g., at the center) as shown in  FIG.  10 A  in one embodiment. The plurality of impact reduction pads  1005  may include a first impact reduction pad  1005 A mounted at one side (e.g., left side) of the shock absorber  1003  and a second impact reduction pad  1005 B mounted at a second side (e.g., right side) of the shock absorber  1003 . The plurality of impact reduction pads  1005  are mounted on the lowermost horizontal side  803  of the rail stage. The plurality of impact reduction pads  1005  are made of a material that is more elastic than the lowermost horizontal side  803  of the rail stage. For example, the impact reduction pads  1005  may be made of urethane, but other materials may be used. 
     In one embodiment, intermediate rail stages  801 B to  801 C may include the shock reducing unit  1000 A at the top of the rail stage and the shock reducing unit  1000 B at the bottom of the rail stage  801 . In contrast, end rail stages  801 A and  801 D may include one of shock reducing unit  1000 A or  1000 B. For example, rail stage  801 A may include shock reducing unit  1000 B at the bottom of the rail stage  801 A without any shock reducing unit  1000  at the top of the rail stage whereas rail stage  801 D may include shock reducing unit  1000 A at the top of the rail stage  801 D without any shock reducing unit  1000 B at the bottom of the rail stage  801 D. 
       FIGS.  10 B and  10 C  illustrate usage of the shock reducing unit  1000 B as the telescoping unit  304  is collapsed according to one embodiment.  FIG.  10 B  illustrates a shock reducing unit  1000 B of a rail stage  801 . The shock reducing unit  1000 B includes an impact reduction block  1001 .  FIG.  10 C  illustrates as the telescoping unit  304  is collapsed, the shock reducing unit  1000 B buffers the impact between the two adjacent rail stages  801 . In  FIG.  10 C , the impact reduction block  1001  reduced the amount of impact between adjacent rail stages as the impact reduction block  1001  contacts the horizontal side  803  of the adjacent rail stage. Since the impact reduction block  1001  is made of a material (e.g., urethane) that is more elastic than the horizontal side  803  of the adjacent rail stage, the impact reduction block  1001  dampens the shock between adjacent rail stages when the rail stages come into contact. 
       FIGS.  10 D and  10 E  illustrate usage of the shock reducing unit  1000 A as the telescoping unit  304  is expanded according to one embodiment.  FIGS.  10 D and  10 E  illustrate a shock reducing unit  1000 A of a rail stage  801 . The shock reducing unit  1000 A includes a shock absorber  1003  and a plurality of impact reduction pads  1005 . In one embodiment, the telescoping unit  304  may expand at a faster speed than it can collapse given gravity. Thus, a shock absorber  1003  may be employed to protect the telescoping unit  304  from damage during expansion. 
       FIGS.  10 D and  10 E  illustrate as the telescoping unit  304  is expanded, the shock reducing unit  1000 B buffers the impact between the two adjacent rail stages  801 . In  FIGS.  10 D and  10 E , the shock absorber  1003  initially contacts the horizontal side  803  of the adjacent rail stage as the telescoping unit  304  is expanded. The shock absorber  1003  slows the speed at which the two rail stages contact each other. The plurality of impact reduction pads  1005  contact the horizontal side  803  of the adjacent rail stage to further dampen the impact of collision between adjacent rail stages to reduce the damage to the telescoping unit  304  during expansion of the telescoping unit  304 . 
       FIG.  11    illustrates a detailed view of a mechanism for retracting and collapsing the telescoping unit of the first wash stage  103  according to one embodiment. As mentioned previously, the first wash stage includes a motor  305  connected to the telescoping unit  304 . The first wash stage  103  also includes a wire  319  including a first end connected to a drum  321  (shown in  FIG.  12   ) and a second end connected to the telescoping unit  304 . In one embodiment, the second end of the wire  319  is connected to the bottommost horizontal side  803  for the last rail stage  801 D. 
     In one embodiment, the telescoping unit  304  is collapsed or expanded as a result of the motor  305  respectively raising or lowering the wire  319  via the drum  321  according to the contour profile of a vehicle  101 . The controller  109  uses the vertical contour profile of the vehicle  101  to control an amount in which the motor  305  rotates to raise or lower the wire  319  to achieve the various height points described in the vertical contour profile of the vehicle  101 . As will be described further below, in one embodiment a lookup table may be stored that translates the number of turns required by the motor  305  to achieve an amount of vertical movement that is mapped to a specific height point in the vertical contour profile of the vehicle  101 . 
     For example, assuming that the telescoping unit  304  is in the fully expanded state or in an intermediate state between fully expanded and fully collapsed, as the motor  305  raises the wire  319 , each of the plurality of rail stages  801  of the telescoping unit  304  are raised and become housed within an adjacent rail stage as previously described above. The plurality of rail stages  801  can be raised by the motor  305  and the wire  319  until the telescoping unit  304  is in the fully collapsed state or an intermediate state between fully collapsed or fully expanded. 
     Conversely, assuming that the telescoping unit  304  is in the fully collapsed state or at an intermediate state between fully collapsed and fully expanded, as the motor  305  lowers the wire  319 , the plurality of rail stages  801  of the telescoping unit  304  expands. The plurality of rail stages  801  can be lowered by the motor  305  and wire  319  until the telescoping unit  304  is in the fully expanded state or an intermediate state between fully collapsed or fully expanded. 
     In one embodiment, the motor  305  applies only a vertical force to the wire  319  to retract or expand the telescoping unit  304 . That is, the motor  305  applies force to the wire  319  in the vertical direction to retract or expand the telescoping unit  304 , but not the horizontal direction. However, given that the telescoping unit  304  is positioned at an angle, the telescoping unit  304  moves in both the vertical direction and the horizontal direction responsive to the vertical force applied by the motor  305  in retracting the telescoping unit  304  or expanding the telescoping unit  304 . 
     In one embodiment, the wire  319  is made of a flexible material such as high-modulus polyethylene (e.g., ultra-high-molecular-weight polyethylene (UHMWPE)) which is typically used in marine applications (e.g., boats). However, other embodiments may use different material than UHMWPE. The wire  319  may have a thickness of 0.3 inches and is 165 inches in length in one embodiment. However, other wire thicknesses and lengths may be used in other embodiments. 
       FIGS.  12 A,  12 B, and  12 C  illustrate detailed views of a drum  321  and wire  319  for expanding and collapsing the telescoping rail  304  of the first wash stage  103  according to one embodiment. Referring to  FIG.  12 A , the first wash stage  101  further includes the drum  321 . The drum  321  may be made of nylon and have a diameter of 7.8 inches for example. Other materials and sizes for the drum  321  may be used in other embodiments. 
     The drum  321  is coupled to the motor  304  and one end of the wire  319  is connected to the drum  321  in one embodiment. As the motor  304  rotates, the drum  321  also rotates thereby wrapping the wire  319  around the drum  321  or unwrapping the wire  319  from the drum  321 . For example, if the drum  321  rotates clockwise, the telescoping rail  304  is collapsed as the wire  319  wraps around the drum  321 . If the drum  321  rotates counterclockwise, the telescoping rail  304  expands thereby unwrapping the wire  319  from around the drum  321 . 
       FIGS.  12 B and  12 C  are cross-section views of the drum  321  along line A-A′ according to one embodiment. In one embodiment, the drum  321  includes a plurality of grooves  1201 . The wire  319  is disposed within the plurality of grooves  1201  as the wire  319  is wrapped around the drum  321 . In one embodiment, the diameter of the wire  319  is larger than the depth of the plurality of grooves  1201 . This reduces the likelihood of the write  319  breaking as it is wound or unwound from the drum  321 . 
     Wash Unit  306   
       FIGS.  13 A- 13 D  illustrate detailed views of the wash unit  306 . In one embodiment, the wash unit  306  include a front manifold  306 A and a rear manifold  306 B. The front manifold  306 A is a chamber that houses water used to wash the front and top surfaces of the vehicle  101  whereas the rear manifold  306 B is a chamber that houses water used to wash the rear surface of the vehicle  101 . The front and rear manifolds  306 A,  306 B may be made of metal such as stainless steel, but other materials may be used. 
       FIG.  13 A  shows a perspective view of the wash unit  306  and  FIG.  13 B  shows a side view of the wash unit  306  in one embodiment. As shown in  FIG.  13 A , the front manifold  306 A and the rear manifold  306 B have a pipe shape. The length of the front and rear manifolds  306  is 63 inches with a diameter of 1 inch in one embodiment. The front manifold  306 A and the rear manifold  306 B are attached to the bottom end of the last rail stage  801 D of the telescoping unit  304  in one embodiment. The front manifold  306 A and the rear manifold  306 B may be attached to the end of the rail stage  801  using couplers  1303 A and  1303 B. The couplers  13013  are disposed at each side of the end of the last rail stage  801 D and surround at least a portion of the front manifold  306 A and the rear manifold  306 B as shown in  FIGS.  13 A and  13 B . 
     In one embodiment, the front manifold  306 A includes an input port  1301 A connected to the water supply line  303 A. The input port  1301 A supplies water provided by the water supply line  303 A to the front manifold  306 A. The rear manifold  306 B includes an input port  1301 B connected to the water supply line  303 B. The input port  1301 B supplies water provided by the water supply line  303 B to the rear manifold  306 B. 
     The front manifold  306 A sprays the water supplied by the water supply line  303 A using a plurality of nozzles  1305  shown in  FIG.  13 C . As mentioned previously, the front manifold  306 A is used to wash the front and top surfaces of the vehicle  101  until the front and top surfaces are no longer overlapping with the front manifold  306 A. In one embodiment, the nozzles  1305  are equally spaced apart from each other. For example, each nozzle  1305  may be spaced apart from an adjacent nozzle  1305  by 10.2 inches. Other distance spacing between nozzles may be used. In one embodiment, the water sprayed from each nozzle  1305  creates an overlap section  1309  with water sprayed by an adjacent nozzle  1305 . By overlapping the sprayed water to create the overlap section  1309 , cleaning efficiency of the front and top surfaces of the vehicle  101  is improved. In one embodiment, the overlap  1309  of water sprayed by adjacent nozzles  1305  is 1.5 inches. 
     The rear manifold  306 B sprays the water supplied by the water supply line  303 B using a plurality of nozzles  1307 . As mentioned previously, the rear manifold  306 B is used to wash the top and back surfaces of the rear of the vehicle  101  while the rear top and back surfaces are overlapping with the rear manifold  306 B. The nozzles  1307  on the rear manifold  306 B and the nozzles  1305  on the front manifold  306 A are interdependently controlled to wash the front, top, and rear surfaces of the vehicle  101  as described below. In one embodiment, the nozzles  1307  are equally spaced apart from each other similar to nozzles  1305 . For example, each nozzle  1307  may be spaced apart from an adjacent nozzle  1307  by 10.2 inches. Other distance spacing between the nozzles  1307  may be used. In one embodiment, the water sprayed from each nozzle  1307  creates an overlap section  1311  with water sprayed by an adjacent nozzle  1307 . By overlapping the sprayed water to create the overlap section  1311 , cleaning efficiency of the rear surface of the vehicle  101  is improved. In one embodiment, the overlap  1311  of water sprayed by adjacent nozzles  1307  is 1.5 inches. 
       FIG.  13 D  illustrates the angle of position of the nozzles  1305  of the front manifold  306 A and the angle of position of the nozzles  1307  of the rear manifold  306 B with respect to reference line  1313  that is parallel to ground according to one embodiment. In one embodiment, the angle  1315  of nozzles  1305  is less than the angle  1317  of nozzles  1307 . For example, the nozzles  1305  of the front manifold  306 A are at an angle of 5 degrees above the reference line  1313  whereas nozzles  1307  of the rear manifold  306 B are at an angle of 60 degrees below the reference line  1313 . The arrangement of the nozzles  1305  and  1307  in combination with the nozzles  1305  and  1307  being kept within the predetermined distance range of the front, top, and rear surfaces of the vehicle  101  provides the most effective washing. Note that the angles of the nozzles  1305  and  1307  are exemplary and other angles may be used in other embodiments. 
       FIG.  14    illustrates another embodiment of the wash unit  306 . In the embodiment of  FIG.  14   , the wash unit  306  includes a tilt device  1405 , a water manifold  1401 , and nozzles  1403  according to one embodiment. In  FIG.  14   , the wash unit  306  includes a single manifold rather than two water manifolds as described in the embodiment of  FIG.  14   . The set of nozzles  1403  rotate about the axis of the water manifold  1401  depending on whether the front, top, and rear surfaces of the vehicle are being washed in one embodiment. That is, the nozzles  1403  may rotate between positions A and B to change the angle of the nozzles  1403  depending on which portion of the vehicle  101  is being washed. The angle of the water manifold  1401  is changed by a tilt device  1405 . The tilt device  1405  may include a gear that spins to change the rotation of the nozzles  1403  between positions A and B. 
     Safety Device  307   
       FIG.  15 A  illustrates a detailed view of the safety device  307  according to one embodiment. As mentioned above, the safety device  307  includes safety device  307 A on a first portion of the wash unit  306  and safety device  307 B on a second portion of the wash unit  306  such that the safety device  307 A and safety device  307 B are spaced apart from each other. The safety device  307  reduces damage to vehicle  101  if there is impact between the telescoping unit  305  and the vehicle  101  due to the material of the safety device  307  and the safety device  307  rolling along the upper surfaces of the vehicle  101  upon contact of the safety device  307  and the vehicle  101 . 
       FIG.  15 B  illustrates an exploded view of the safety device  307 . In one embodiment, each of safety device  307 A and safety device  307 B includes a housing  1501 , an damage mitigator  1503 , a cover  1505 , a bushing  1507 , and a bracket  1509 . The housing  1501  functions as the frame for the safety device  307 A. All of the components of the safety device  307 B attach to the housing  1501 . 
     The housing  1501  includes a groove  1511  in one embodiment. The impact mitigator  1503  is disposed within the groove  1511  of the housing  1501 . As shown in  FIG.  15 B , the impact mitigator  1503  has a ring shape with a curved surface in one embodiment. Due to the curved surface of the damage mitigator  1503 , the groove  1511  also has a curved surface that corresponds to the curvature of the damage mitigator  1503  to ensure a snug fit of the damage mitigator  1503  within the groove  1511 . 
     The damage mitigator  1503  is made of elastic material so as to reduce damage to the vehicle  101  upon contact between the safety device  307  and the vehicle  101 . For example, the damage mitigator  1503  is made of shock absorbent material such as ethylene propylene diene monomer (EPDM). In one embodiment, in the case of contact, the only portion of the safety device  307  that contacts the vehicle is damage mitigator  1503 . Damage to the vehicle  101  is reduced due to impact absorption by the damage mitigator  1503  and rolling of the safety device  307  while the safety device  307  is in contact with the vehicle  101 . 
     In one embodiment, the bushing  1507  is inserted in a hole at the center of the housing  1501 . The bushing  1507  may be a sleeve bearing for example. The bracket  1509  is inserted into the bushing  1507  such that the bracket  1509  is disposed at one side of the housing  1501  (e.g., left side). The bracket  1509  includes a plurality of holes  1513  which are aligned with holes  1515  on the housing  1501  and holes  1517  on the cover  1505 . The cover  1505  is inserted into another side of the housing  1501  (e.g., right side). Fasteners (e.g., screws, nuts, bolts, etc.) may be used to secure the bracket  1509 , housing  1501 , and cover  1505  together. 
     Rotation Apparatus  1600   
       FIG.  16 A  illustrates a collision between the vehicle  101  and the safety device  307  during the first wash stage  103 . In one embodiment, the first wash stage  103  includes a rotation apparatus  1600  shown in  FIGS.  16 B- 16 C  that rotates the telescoping unit  304  in response to a collision between the vehicle  101  and the safety device  101 . In one embodiment, the rotation apparatus  1600  is a passive device. The force of a collision between the vehicle  101  and the safety device  307  causes the rotation apparatus  1600  to rotate the telescoping unit  304  about the hinge point  1608  thereby increasing the angle α between the telescoping unit  304  and reference line  701 . As mentioned previously, the telescoping unit  304  is positioned between the angle range of 13 to 17 degrees from the reference  701  during normal operation of the first wash stage  103 . However, if a collision occurs between the vehicle  101  and the safety device  307 , the telescoping unit  304  is rotated upward to an angle greater than the angle range of 13 to 17 degrees to prevent or at least reduce any further damage to the vehicle  101 . For example, the rotation apparatus  1600  allows the telescoping unit  304  to rotate upward to an angle up to 60 degrees from the reference  701 . 
     Referring to  FIG.  16 B , the rotational apparatus  1600  is shown according to one embodiment. As shown in  FIG.  16 B , the rotation apparatus  1600  includes a shock  1601 , the hinge point  1608 , and an oil supply  1603  that are mounted to the mounting plate  313  in one embodiment. The shock  1601  includes a first end connected to the telescoping unit  304  and a second end connected to the mounting plate  313 . The first end of the shock  1601  may be connected to a horizontal side  803  of one of the plurality of rail stages  801  such as a horizontal side  803  of the rail stage  801 A. The oil supply  1603  is coupled to the shock  1601  to supply the shock  1601  with oil. 
     To reduce damage to the vehicle  101 , the telescoping unit  304  rotates about the hinge point  1608  upward upon impact between the vehicle  101  and the safety device  307 . As mentioned above, the telescoping unit  304  rotates due to the force from the collision between the vehicle  101  and the safety device  307 . 
     In one embodiment, pressure is always supplied to the oil supply  1603  that applies oil to the shock  1601 . As a result, the shock  1601  applies a constant force on the telescoping unit  304  to reduce the weight of the telescoping unit  304  as the telescoping unit  304  rotates about the hinge point  1608 . When the vehicle  101  clears the first wash stage  103 , the telescoping unit  304  returns to its initial position due to gravity and the weight of the telescoping unit  304 . In one embodiment, the shock  1601  slows the rate in which the angle of the telescoping unit  304  is returned back to its initial position by applying the constant force to the telescoping unit  304 . However, the weight of the telescoping unit  304  and gravity are enough to overcome the force applied by shock  1601 , but the shock is still able to slow the rate in which the telescoping unit  304  returns back to its initial angle. If the first wash stage  103  lacked the shock  1601  and oil supply  1603 , the telescoping unit  304  would quickly return to its initial angle prior to collision thereby increasing the likelihood of damage to the first wash stage  103 . 
     Overview of a First Embodiment of the Second Wash Stage  105   
     Referring to  FIG.  17   , a perspective view of the second wash stage  105  of the car wash system  100  is shown according to one embodiment. In one embodiment, the second wash stage  105  includes a frame  1701 , a plurality of arms  1703 , a plurality of base assemblies  1705 , a plurality of nozzle assemblies  1707 , a plurality of collision prevention units  1709 , intermediate stop circuit lines  1711 , and cylinders  1713  that are each described in further detail below. However, the second wash stage  105  may have additional or fewer components than described herein. 
     The frame  1701  is a structure used to support the other components of the second wash stage  105 . For example, one end of each of the plurality of arms  1703  is attached to the frame  1701  and the base assemblies  1705  that are attached to a second end of the plurality of arms  1703  are floating (e.g., hanging) so as not to contact the ground. In particular, the plurality of arms  1703  are attached to mounting plates  1701 D included in the frame  1701 . In one embodiment, the plurality of arms  1703  and the plurality of base assemblies  1705  are collectively considered a width adjusting unit of the second wash stage  105 . 
     The frame  1701  includes a plurality of frame rails that collectively form the frame  1701 . Frame rails  1701 A to  1701 C shown in  FIG.  17    are merely examples of horizontal and vertical frame rails. The frame  1701  may be made of metal such as steel or aluminum or other metals. The frame  1701  has a height greater than 90 inches (e.g., 119.7 inches) and a width greater than 126 inches (e.g., 165.4 inches) in one embodiment. This allows for the second wash stage  105  to accommodate vehicles  101  with a maximum height of 90 inches and a maximum width of 126 inches. However, the frame  1701  may have different dimensions depending on the size of the vehicles being washed. 
     In one embodiment, the plurality of arms  1703  support the base assemblies  1705 . The plurality of arms  1703  includes a first set of arms and a second set of arms. Each set of arms is configured to connect to one of the plurality of base assemblies  1705 . For example, the first set of arms includes arms  1703 A and  1703 B that connect the base assembly  1705 A (e.g., a driver side base assembly) to the frame  1701 . The second set of arms include arms  1703 C and  1703 D that connect the base assembly  1705 B (e.g., a passenger side base assembly) to the frame  1701 . As shown in  FIG.  17   , the base assemblies  1705  are floating off the ground (not in contact) due to being connected to the arms  1703 . 
     In one embodiment, the base assemblies  1705  adjust the variable width of the second wash stage  105 . Generally, base assemblies  1705  are floating off the ground by hanging from the frame  1701  via the hanging arms  1703  (e.g., the base assemblies  1705  are floating above ground level) and contact the vehicle  101  to adjust the width of the second wash stage  105  based on the width of the vehicle  101 . As will be further described below, the base assemblies  1705  contact tires of the vehicle  101  which thereby push the base assemblies  1705  outward to adjust the width of the second wash stage  105  in accordance with the width of the vehicle  101 . 
     In one embodiment, a plurality of nozzle assemblies  1707  (e.g., a wash unit) wash vehicle  101  by spraying water on the side surfaces of the vehicle  101 . In other embodiments, the nozzle assemblies  1707  may spray detergent such as soap in addition to water. The nozzle assemblies  1707  are installed on the base assemblies  1705  as shown in  FIG.  17   , so that the nozzle assemblies  1707  are also floating off the ground. 
     In one embodiment, each nozzle assembly  1707  is mounted to a corresponding one of the base assemblies  1705 . For example, nozzle assembly  1707 A is mounted to base assembly  1705 A and nozzle assembly  1707 B is mounted to base assembly  1705 B. Since the nozzle assemblies  1707  are mounted on the base assemblies  1705 , the lateral position of the nozzle assemblies  1707  change based on the width of the vehicle  101  being washed. Thus, the distance from the nozzle assemblies  1707  to the side surfaces of the vehicle  101  being washed can be kept within a predetermined distance range that improves cleaning efficiency of the side surfaces of the vehicle compared to conventional car wash systems with nozzle assemblies that have static positions. 
     Water supply lines  1717  supply water to the nozzle assemblies  1707 . Each water supply line  1717  is connected to a corresponding one of the nozzle assemblies  1707 . For example, a water supply line is connected to nozzle assembly  1707 A and a water supply line is connected to nozzle assembly  1707 B. 
     In one embodiment, the plurality of collision prevention units  1709  prevent the base assemblies  1705  from being positioned underneath the vehicle  101 . The plurality of collision prevention units  1709  may contact the side surface of the vehicle  101  thereby preventing the base assemblies  1705  from further moving inward toward the center of the second wash stage  105 . If the base assemblies  1705  were to move toward the center of the second wash stage  105 , the base assemblies  1705  may go underneath the vehicle  101  and may damage the vehicle  101  upon contact with the underside of the vehicle  101 . Furthermore, the nozzles assemblies  1705  may contact the side surfaces of the vehicle  101  if the base assemblies  1705  go underneath the vehicle  101 . Thus, the collision prevention units  1709  prevent the nozzle assemblies  1705  from colliding with the side surfaces of the vehicle  101  as further described below. In one embodiment, the plurality of collision prevention units  1709  include stop device  1709 A and stop device  1709 B. Stop device  1709 A is mounted to nozzle assembly  1707 A whereas stop device  170 B is mounted to nozzle assembly  1707 B in one example. 
     In one embodiment, a plurality of cylinders  1713  reduce shaking of the base assemblies  1705  during operation of the second wash stage  105 . The plurality of cylinders  1713  may also be locked in place after the width of the second wash stage  105  is set in one embodiment. By locking the cylinders  1713 , the base assemblies  1705  cannot move so as to be positioned under the vehicle  101  when the base assemblies  1705  are no longer in contact with the tires of the vehicle  101  as will be further described below. 
     In one embodiment, the plurality of cylinders  1713  include cylinder  1713 A and cylinder  1713 B where each cylinder  1713  is coupled to a corresponding one of the plurality of base assemblies  1705 . For example, cylinder  1713 B is attached to base assembly  1705 B whereas cylinder  1713 A is attached to base assembly  1705 . Each cylinder  1713  includes two ends with one end of the cylinder  1713  attached to the frame  1701  and another end of the cylinder  1713  attached to the base assembly  1705 . For example, one end of cylinder  1713 B is attached to frame rail  1701 C and the other end of the cylinder  1713 B is attached to base assembly  1705 B. 
     In one embodiment, the plurality of intermediate stop circuit lines  1711  (e.g., air lines) supply air to the plurality of cylinders  1713 . Suppling air to the cylinders  1713  unlocks the cylinders  1713  and allows the cylinders  1713  to return to their original position once vehicle  101  has exited the second wash stage  105 . 
     In one embodiment, the plurality of intermediate stop circuit lines  1711  includes intermediate stop circuit line  1711 A and intermediate stop circuit line  1711 B. Intermediate stop circuit line  1711 A is connected to cylinder  1713 A and supplies air to cylinder  1713 A to unlock or lock cylinder  1713 A. Similarly, intermediate stop circuit line  1711 B is connected to cylinder  1713 B and supplies air to cylinder  1713 B to unlock or lock cylinder  1713 B. 
     Operation of the First Embodiment of the Second Wash Stage  105   
       FIGS.  18 A to  18 D  illustrate operation of the second wash stage  105  to wash side surfaces of the vehicle  101  according to one embodiment.  FIG.  18 A  illustrates the adjustment operation during the second wash stage  105  operation. Generally, the second wash stage  105  has a variable width to account for the contour of the side surfaces of the vehicle  101  while washing the side surfaces of the vehicle  101 . During the initial adjustment operation, the width of the second wash stage  105  is adjusted according to the width of the vehicle  101 . 
     As shown in  FIG.  18 A , the tires  1801  of the vehicle  101  contact the plurality of base assemblies  1705  as the vehicle  101  approaches the second wash stage  105 . As the vehicle  101  moves forward due to the conveyer moving the vehicle  101  forward, the base assemblies  1705  are pushed outward away from the center of the second wash stage  105 B by being in contact with the tires  1801  to set the width of the second wash stage  105  as shown in  FIG.  18 B . Thus, the sides of the vehicle (e.g., the sides of the tires) are in physical contact with the second wash stage  105  to set the width of the second wash stage  105  according to the width of the vehicle  101 . 
       FIG.  18 B  illustrates the initial wash operation of the second wash stage  105  in one embodiment. Once the width of the second wash stage  105  is adjusted according to the width of the vehicle  101 , the cylinders  1713  are activated by the controller  109  so as to lock the length of the cylinders  1713  in place during the initial wash stage in one embodiment. By locking the cylinders  1713 , the width of the second wash stage  105  is thereby locked in place. The nozzle assemblies  1707  can then begin washing the front portion of the side surfaces (e.g., the sides of the front fenders) of the vehicle  101 . The nozzle assemblies  1707  may wash the front portion of the side surface of the vehicle  101  using water output by the nozzle assemblies  1707  or a combination of water and detergent (e.g., soap) output by the nozzle assemblies  1707 . If the nozzle assemblies  1707  output only water, the second wash stage  105  relies upon the detergent output by the chemical arches  401  in the first wash stage  103  to aid in cleaning the vehicle  101 . 
       FIG.  18 C  illustrates an intermediate wash operation of the second wash stage  105  in one embodiment. As the vehicle  101  continues to move along the second wash stage  105 , nozzle assemblies  1707  continue to wash the side surfaces of the vehicle  101  such as the center portion of the side surfaces of the vehicle (e.g., the doors) and the rear portion of the side surfaces of the vehicle (e.g., rear fenders). As shown in  FIG.  18 C , at one point during the second wash stage  105 , the base assemblies  1705  are no longer in contact with the vehicle  101  due to the length of the base assemblies  1705  not being long enough to span the length of the wheelbase of the vehicle  101 . Thus, the base assemblies  1705  are only capable of contacting either the front tires or the rear tires, but cannot simultaneously contact both the front tires and rear tires due to the short length of the base assemblies  1705 . 
     Even though the base assemblies  1705  are no longer in contact with the tires  1801  of the vehicle  101  as shown in  FIG.  18 C , the width of the second wash stage  105  is maintained due to the cylinders  1713  locking the width of the second wash stage  105 . As mentioned previously, locking the cylinders  1713  prevents the base assemblies  1705  from moving underneath the vehicle  101  during the intermediate wash operation. 
     Although not shown, the cylinders  1713  include a number of components such as various solenoids and valves to control the lock and unlock operation of the cylinders  1713 . As mentioned above, the intermediate stop circuit lines  1711  supply air to the cylinders  1713 . When the vehicle  101  has yet to contact the base assemblies  1705 , the intermediate stop circuit lines  1711  do not supply air to the cylinders  1713 . When air is not supplied to the cylinders  1713 , the cylinders  1713  can expand or contract. Thus, the cylinders  1713  are unlocked. 
     When the vehicle  101  contacts the base assemblies  1705 , the intermediate stop circuit lines  1711  supply air to cylinders  1713 . The supplied air to the cylinders  1713  allows the cylinders  1713  to further contract, but do not allow the cylinders  1713  to expand thereby locking the cylinders  1713  in place. Thus, the base assemblies  1705  that are connected to the cylinders  1713  can move outward away from the vehicle  101  during the second wash stage  105 , but cannot move inward toward the vehicle  101  during the second wash stage. In other words, the cylinders  1713  are locked thereby preventing the base assemblies  1705  from moving inward. 
       FIG.  18 D  illustrates the reset operation of the second wash stage  105  in one embodiment. After the vehicle  101  has exited the second wash stage  105 , the width of the second wash stage  105  is reset to its initial position. In one embodiment, the width of the second wash stage  101  is reset by unlocking cylinders  1713 . By unlocking the cylinders  1713 , the base assemblies  1705  are able to move back to their initial position. As will be described below with respect to  FIG.  20   , the base assemblies  1705  may move to their initial position using gravity which causes the base assemblies  1705  and arms  1703  to move inward toward the center of the second wash stage  105 . 
     To unlock the cylinders  1713 , the intermediate stop circuit lines  1711  stops supplying air to the cylinders  1713 . Once the cylinders  1713  are unlocked, the base assemblies  1705  return to their initial position using gravity and the weight of the base assemblies  1705  as described above. In one embodiment, the intermediate stop circuit lines  1711  stop supplying air to the cylinders  1713  a threshold amount of time (e.g., 2 seconds) after the vehicle  101  has exited the second wash stage  105  thereby causing the base assemblies  1705  to return to their initial position. Alternatively, the intermediate stop circuit lines  1711  do not supply air to the cylinders  1713  based on a signal received from a photo sensor at the entry of the car was system  100  that is different from the optical sensor  301 . The timing in which the optical sensor sends the signal is calculated based on the speed of the conveyer  107 . Based on the speed of the conveyer  107  and the length of the car wash  100 , the time it takes for a vehicle to exit the second wash stage  105  can be calculated. 
     After the second wash stage  105  is completed, the vehicle  101  may be dried by one or more fans or blowers (not shown). The fans generate wind that dry the surfaces of the vehicle  101  washed by the first wash stage  103  and the second wash stage  105 . 
     Arms  1703   
     Generally, the arms  1703  connect the hanging base assemblies  1705  to the top of the frame  1701 . The arms  1703  may have different shapes in different embodiments.  FIG.  19    illustrates a front view of the second wash stage  105  to illustrate an example shape of the plurality of arms  1703 . As shown in  FIG.  19   , the arms  1703  each include at least one bend in one embodiment. By having at least one bend in each of the arms  1703 , the likelihood of contact between the vehicle  101  and the arms  1703  is reduced compared to if the arms  1703  were straight (e.g., lack any bends). If the arms were straight, there is a high likelihood of contact between side view mirrors of the vehicle  101  and the arms  1703 . The at least one bend in each arm  1703  is located at the end of the arm that is closest to the base assembly  1705  in one embodiment. 
     The example of  FIG.  19    illustrates a “C” shaped arm that includes a plurality of bends (e.g., two bends) according to one embodiment. Each of the “C” shaped arms  1703 A- 1703 D shown in  FIG.  19    includes an upper part  1903 , a center part  1905 , and a lower part  1907 . A first bend  1909  is formed between the upper part  1903  and the center part  1905  and a second bend  1911  is formed between the center part  1905  and the lower part  1907 . For example, arm  1703 A includes an upper part  1903 A, a center part  1905 A, and a lower part  1907 A with a first bend  1909 A formed between the upper part  1903 A and the center part  1905 A and a second bend  1911 A formed between the center part  1905 A and the lower part  1907 A. Arm  1703 B includes an upper part  1903 B, a center part  1905 B, and a lower part  1907 B with a first bend  1909 B formed between the upper part  1903 B and the center part  1905 B and a second bend  1911 B formed between the center part  1905 B and the lower part  1907 B. Arm  1703 C includes an upper part  1903 C, a center part  1905 C, and a lower part  1907 C with a first bend  1909 C formed between the upper part  1903 C and the center part  1905 C and a second bend  1911 C formed between the center part  1905 C and the lower part  1907 C. Arm  1703 D includes an upper part  1903 D, a center part  1905 D, and a lower part  1907 D with a first bend  1909 D formed between the upper part  1903 D and the center part  1905 D and a second bend  1911 D formed between the center part  1905 D and the lower part  1907 D. 
     In one embodiment, the upper part  1903  and the lower part  1907  of the “C” shaped arms are symmetrical. That is, the upper part  1903  and the lower part  1907  of the “C” shaped arms  1703  have a same length. Furthermore, the angle between the upper part  1903  and the center part  1905  of the “C” shaped arms  1703  is the same as the angle between the lower part  1907  and the center part  1905  of the “C” shaped arms  1703  in one embodiment. By having upper and lower parts with the same length and the same angle between the upper part and the center part and between the lower part and center part, the ability of the “C” shaped arms  1703  to return to their initial position due to the weight of the arms  1703  and gravity after the vehicle  101  has left the second wash stage  105  is improved as further described below with respect to  FIGS.  20 A and  20 B . 
       FIG.  20 A  illustrates the orientation of an arm  1703  after the arm  1703  has been pushed outward from the center of the second wash stage  105  due to the vehicle  101  being in contact with the base assemblies  1705 . Arm  1703  shown in  FIG.  20    may represent the arms on the right side of the second wash stage  105 . As shown in  FIG.  20 A , the center part  1905  of the arm  1703  is vertical (e.g., normal to ground) while the width of the second wash stage  105  is adjusted for the vehicle  101 . While the arm  1703  is oriented such that the center part  1905  is in the vertical position, the center of gravity of the arm  2003  is located to the right side of the hinge point  2001  of the arm  1703 . That is, the hinge point  2001  is misaligned with the center of gravity  2003  of the arm  1703 . The hinge point  2001  is the part of the arm  1703  that connects to the frame  1701 . 
       FIG.  20 B  illustrates the orientation of the arm  1703  in its initial reset position after the vehicle  101  has left the second wash stage  105 . In  FIG.  20 B , the arm  1703  rotates clockwise about the hinge point  2001  due to gravity until the arm  1703  reaches its initial reset position. At the initial reset position of the arm  1703 , the center of gravity  2003  of the arm  1703  is aligned with the hinge point  2001  of the arm  1703  in one embodiment. 
     In one embodiment, weights  2005  may be placed on the “C” shaped arms to adjust the center of gravity of the arms  1703  as shown in  FIGS.  20 C and  20 D . A weight  2005  may be placed on the center part  1905  of the arm  1703  as shown in  FIG.  20 C  to adjust the center of gravity of the arm  1703 . Alternatively, a weight  2005  may be placed on the upper part  1903  of the arm  1703 . By changing the center of gravity of the arms  1703  using weights  2005 , the arms  1703  may more easily return to their initial reset position after the vehicle  101  leaves the second wash stage  105  compared to the embodiment without the weights  2005  due to the weight  2005  adding more mass to the arms  1703 . 
     The above description of the center of gravity of the arm  1703  is applicable to the arms positioned at the left side of the second wash stage  105 . However, while the arms  1703  positioned at the left side of the second wash stage  105  are oriented such that the center part  1905  of the arms are in the vertical position, the center of gravity of the arm  1703  is located to the left side of the hinge point  2001  of the arm  1703  rather than the right side as shown in  FIG.  20 A . 
       FIG.  21    illustrates a front view of the second wash stage  105  to illustrate another shape of the plurality of arms  1703  according to one embodiment. In comparison to the embodiment shown in  FIG.  19   , the arms  1703  shown in  FIG.  21    each include one bend in one embodiment. By having a single bend in each of the arms  1703 , the likelihood of contact between the vehicle  101  and the arms  1703  is reduced compared to if the arms  1703  were straight (e.g., lack any bends) similar to the embodiment shown in  FIG.  19   . If the arms were straight, there is a high likelihood of contact between side view mirrors of the vehicle  101  and the arms  1703 . The at least one bend in each arm  1703  is located at the end of the arm that is closest to the base assembly  1705 . 
     The example of  FIG.  21    illustrates an “L” shaped arm that includes a single bend (e.g., one bend) according to one embodiment. Each of the “L” shaped arms  1703 A- 1703 D shown in  FIG.  21    includes an upper part  2101  and a lower part  2103 . A bend  2105  is formed between the upper part  2101  and the lower part  2103 . For example, arm  1703 A includes an upper part  2101 A and a lower part  2103 A with a bend  2105 A formed between the upper part  2101 A and the lower part  2103 A. Arm  1703 B includes an upper part  2101 B and a lower part  2103 B with a bend  2105 B formed between the upper part  2101 B and the lower part  2103 B. Arm  1703 C includes an upper part  2101 C and a lower part  2103 C with a bend  2105 C formed between the upper part  2101 C and the lower part  2103 C. Arm  1703 D includes an upper part  2101 D and a lower part  2103 D with a bend  2105 D formed between the upper part  2101 D and the lower part  2103 D. 
       FIG.  22 A  illustrates a side view of the arms  1703 C and  1703 D positioned at the right side of the second wash stage  105  according to one embodiment. Although  FIG.  22 A  does not show arms  1703 A and  1703 B positioned at the left side of the second wash stage  105 , the description of  FIG.  22 A  is also applicable to arms  1703 A and  1703 B. 
     As shown in  FIG.  22 A , the hinge points  2001  of arms  1703 C and  1703 D are attached to the mounting plate  1701 D of frame  1701 . In one embodiment, the hinge points  2001  are separated by a threshold distance “E”. The threshold distance “E” is 20.9 inches according to one embodiment. If the hinge points  2001  are separated by a distance less than the threshold distance “E”, the arms  1703  and base assemblies  1705  shake upon the initial impact between the tires  1801  and the base assemblies  1705 . By separating the hinge points  2001  of the arms  1703  by the threshold distance “E,” shaking of the arms  1703  and base assemblies  1705  are reduced. 
       FIG.  22 A  also illustrates the path of motion  2201  of the base assemblies  1705  as the base assemblies  1705  are repositioned in accordance with the width of the vehicle  101 . The path of motion  2201  is not in a straight line such as the horizontal direction. Rather, the path of motion  2201  of the base assemblies  1705  is in an arc (e.g., crescent shape) given that each arm  1703  is attached to the mounting plate  1701 D by a single hinge point  2001 . During the movement in the path of motion  2201 , the nozzles of the water assemblies  1707  remain substantially flat to ensure optimum washing efficiency. 
       FIG.  22 B  is a force diagram describing the forces applied to the base assembly  1705  to adjust the width of the second wash stage  105  according to one embodiment. A plan view of a portion of the base assembly  1705  is shown. Vector  2203  represents the direction and force applied by the tire  1801  on the vehicle entry guide of the base assembly  1705  (described below). Vector  2211  represents the reaction force in the left direction in response to the force applied by the tire  1801  and vector  2209  is the reaction force opposite the vector  2201 . The sum of the vectors  2203 ,  2209 , and  2211  results in vector  2201  that represents the path of motion of the base assembly  1705 . 
     The vehicle entry guide of the base assembly  1705  is set at an angle  2207  with respect to the reference line  2205 . In one embodiment the angle is 45 degrees, but other angles may be used. If the 45-degree angle is used, the direction of the arm rotation along the path of motion  2201  is formed in a 90-degree direction with the vehicle entry guide  1705 . In general, as the angle of the vehicle entry guide increases, the amount of travel along the path of motion  2201  increases as well as the force applied to the arms  1703 . 
     Base Assemblies  1705   
       FIGS.  23 A and  23 B  illustrate detailed views of the components of base assemblies  1705 A and  1705 B, respectively, according to one embodiment. The base assembly  1705 A includes a base structure  2301 A, a vehicle entry guide  2302 A, impact part  2303 A, impact part  2304 A, bearings  2305 A, and cylinder bracket  2305 A in one embodiment. Similarly, base assembly  1705 B includes a base structure  2301 B, a vehicle entry guide  2302 B, impact part  2303 B, impact part  2304 B, bearings  2305 B, and cylinder bracket  2305 B in one embodiment. 
     The base structure  2301  functions as the frame of the base assembly  1705  to support the components of the base assembly  1705 . The vehicle entry guide  2302 , bearings  2305 , cylinder bracket  2305 , water assembly  1707 , and impact part  2302 A all attach to the base structure  2301  in on embodiment. The base structure  2301  is rectangular in shape and may be made of metal such as aluminum, but other shapes and materials may be used. 
     Impact part  2303  is attached to the base structure  2301 . The impact part  2303  may be attached to an edge of the base structure  2301  using fasteners such as screws or nuts and bolts. The impact part  2303  is configured to protect the base structure  2301  from damage while the tires  1801  of the vehicle  101  are in contact with the base assembly  1705 . Since the impact part  2303  is in contact with the tires, the impact part  2303  must also not impede the travel of the vehicle  101  through the second wash stage  105 . Thus, the impact part  2303  is made of a material strong enough to protect the base structure  2301  while having low friction to allow the tires to smoothly glide along the impact part  2303 . In one embodiment, the impact part  2303  is made of plastic such as polyethylene, but other materials may be used. 
     The vehicle entry guide  2302  guides the vehicle  101  into the second wash stage  105 . As mentioned previously, the vehicle entry guide  2302  is angled such as at an angle of 45 degrees with respect to reference line  2205 . The vehicle entry guide  2302  impacts the tires  1801  of the vehicle  101  to adjust the width of the second wash stage  105 . The vehicle entry guide  2302  is triangular in shape and may be made of metal such as aluminum, but other shapes and materials may be used. 
     Impact part  2304  is attached to the vehicle entry guide  2302 . The impact part  2304  may be attached to an edge of the vehicle entry guide  2302  using fasteners such as screws or nuts and bolts. The impact part  2304  is configured to protect the vehicle entry guide  2302  from damage while the tires  1801  of the vehicle  101  are in contact with the vehicle entry guide  2302 . Since the impact part  2304  is in contact with the tires, the impact part  2304  must also not impede the travel of the vehicle  101  through the second wash stage  105 . Thus, the impact part  2304  is made of a material strong enough to protect the vehicle entry guide  2302  while having low friction to allow the tires to smoothly glide along the impact part  2304 . In one embodiment, the impact part  2304  is made of plastic such as polyethylene, but other materials may be used. 
     In one embodiment, bearings  2305  are hinge points of the base assemblies  1705 . Each bearing  2305  is configured to attach to an end of a corresponding one of the plurality of arms  1703  as shown in  FIG.  23 C . The bearings  2305  allow for the base assemblies  1705  to hang from the arms  1703  resulting in the base assemblies  1705  floating off the ground. The bearings  2305  also allow for the rotation of the base assembly  1705  as the base assembly  1705  travels along the path of motion  2201 . The bearings  2305  may be stainless steel bearings, but other materials may be used for the bearings in other embodiments. 
     Referring back to  FIGS.  23 A and  23 B , bearings  2305  attach to a top surface of the base structure  2301  in one embodiment. Each bearing  2305  may be attached to the top surface of the base structure  2301  using fasteners such as screws or nuts and bolts. As shown in  FIG.  23   , a pair of bearings is attached at one end of the base structure  2301  (e.g., at the corner) and another pair of bearings is attached at another end of the base structure  2301 . 
       FIGS.  24 A and  24 B  illustrate plan views of the base assembly  1705 A and base assembly  1705 B, respectively, according to one embodiment. Specifically,  FIGS.  24 A and  24 B  respectively illustrate hinge points  2401 A and  2403 A of base assembly  1705 A and hinge points  2401 B and  2403 B of base assembly  1705 B. Hinge points  2401  are representative of the location of the pair of bearings  2305  positioned at the top end of the base structure  2301  and hinge points  2403  are representative of the location of the pair of bearings  2305  positioned at the bottom end of the base structure  2301  in one embodiment. 
     As shown in  FIGS.  24 A and  24 B , the hinge points  2401  and  2403  are misaligned in one embodiment. That is, the hinge points  2401  and  2403  are misaligned in both the horizontal and vertical directions. Due to the misalignment, hinge points  2401  and  2403  are offset from each other in both the horizontal and vertical directions. 
     In one embodiment, the hinge points  2401  and  2403  are angled with respect to an edge of the base assembly  1705 . For example, hinge point  2401 A and  2403 A are angled with respect to the edge  2405 A at an angle of 45 degrees in one embodiment, but other angles may be used. Similarly, hinge point  2401 B and  2403 B are angled with respect to the edge  2405 B at an angle of 45 degrees in one embodiment. Angling the hinge points  2401  and  2403  mitigates the impact of the vehicle  101  upon entry and reduces tilting of the base assembly  1705  during the width adjustment of the second wash stage  105 . 
     In one embodiment, the distance  2407  between center points of hinge point  2401  and  2403  is a threshold distance such as 20.9 inches. If the distance between the center points of hinge point  2401  and  2403  is less than the threshold distance, the base assembly  1705  shakes upon impact with the tires  1801  of the vehicle  101 . Having the hinge points  2401  and  2403  separated by the threshold distance reduces shaking upon impact between the base assembly  1705  and the tires  1801 . 
     Referring back to  FIGS.  23 A and  23 B , the cylinder bracket  2305  is attached to the top surface of the base structure  2301  in one embodiment. The cylinder bracket  2305  may be attached to the top surface of the base structure  2301  using fasteners such as screws or nuts and bolts. The cylinder bracket  2305  may be positioned between the pairs of bearings  2305  as shown in  FIG.  23   . For example, the cylinder bracket  2305  is positioned between the pair of bearings at one end of the base structure  2301  and the pair of bearings  2305  at the other end of the base structure  2301 . The cylinder bracket  2305  is configured to attach one end of cylinder  1713  to the top surface of the base structure  2301  in one embodiment as shown in  FIG.  23 C . 
       FIG.  25    illustrates a plan view of the second wash stage  105  to illustrate the angles of the base assembly  1705  and the cylinders  1713  according to one embodiment. As shown in  FIG.  25   , cylinder  1713 A forms an angle  2502 A with respect to reference  2501 A and cylinder  1713 B forms an angle  2502 B with respect to reference  2501 B. Reference  2501 A and reference  2501 B are in in the direction of entry of the vehicle  101 . In one embodiment, the angles formed between the cylinders  1713  and their respective reference  2501  is 45 degrees. Using the 45-degree angle mitigates the impact of the vehicle&#39;s entry with the base assemblies  1705 . Furthermore, as mentioned previously, the angles  2503  (e.g.,  2503 A and  2503 B) formed between the base assembly  1705  with reference line  2205  is also 45 degrees. Thus, the sum of the angles of the cylinders  1703  and the base assemblies  1715  is 90 degrees according to one embodiment. However, other embodiments may have a different sum of angles. 
     Nozzle Assemblies  1707   
       FIGS.  26 A and  26 B  illustrate a detailed view of the nozzle assemblies  1707  included in the second wash stage  105  according to one embodiment. Nozzle assemblies  1707  are examples of the wash unit of the second wash stage  105 . As mentioned previously, the nozzle assemblies  1707  include a nozzle assembly  1707 A configured to wash the side surface of the driver side of the vehicle  101  and a nozzle assembly  1707 B configured to wash the side surface of the passenger side of the vehicle  101  according to one embodiment. 
     As shown in  FIG.  26 A , the nozzle assemblies  1707 A include a support structure  2605 A, a water manifold  2601 A, a plurality of water nozzles  2602 A,  2603 A, and a plurality of fasteners  2604 A according to one embodiment. Similarly, as shown in  FIG.  26 B , the nozzle assemblies  1707 B include a post structure  2605 B, a water manifold  2601 B, a plurality of water nozzles  2602 B,  2603 B, and a plurality of fasteners  2604 B according to one embodiment. As shown in  FIGS.  26 A and  26 B , the passenger and driver side nozzle assemblies include the same types of components in one embodiment. However, the driver and passenger side nozzle assemblies may include different components from each other in other embodiments. 
     In one embodiment, the water manifolds  2601  are chambers that supply water used to wash the side surfaces of the vehicle  101 . For example, the water manifold  2601 A houses water used to wash the driver side of the vehicle  101  and the water manifold  2601 B houses water used to wash the passenger side of the vehicle  101 . Each water manifold  2601  may be a pipe that includes an inlet (e.g.,  2606 A,  2606 B) that is connected to a water supply that supplies water to the water manifold  2601  for washing the vehicle  101 . Each water manifold  2601  may be made of stainless steel and have a diameter of 1.1 inches and a length of 69 inches for example. However, other dimensions and materials may be used for the water manifold  2601 . 
     In one embodiment, the water manifolds  2601  include outlet ports that are each connected to a corresponding one of the plurality of water nozzles  2602  and  2603 . As shown in  FIG.  26   , the water nozzles  2602  and  2603  are disposed across the length of the water manifolds  2601 . The water nozzles  2602  and  2603  may be spaced apart from each other at equal distances in one embodiment. 
     Generally, the water nozzles  2602  and  2603  spray water housed within the water manifolds  2601  onto the side surfaces of the vehicle  101  to wash the vehicle  101 . To improve wash performance, the water nozzles  2602  and  2603  are kept within a predetermined distance range of the side surfaces of the vehicle  101 . The water nozzles  2601  and  2603  are capable of being kept within the predetermined distance range of the side surfaces of the vehicle  101  due to the second wash stage  105  adjusting its width according to the width of the vehicle  101 , as described above. In one embodiment, the distance between the side surface of the vehicle  101  and the tips (e.g., the ends) of the water nozzles  2602  and  2603  is in a range between 10 inches to 15 inches. However, other distances ranges may be used in other examples. 
     In one embodiment, water nozzles  2602  and water nozzles  2603  are configured to clean different parts of the side surface of the vehicle  101 . For example, water nozzles  2603  are configured to wash the side mirror  2604  of the vehicle  101  whereas the water nozzles  2602  are configured to wash remaining side surfaces of the vehicle  101  such as the side of the front bumper, the front fenders, doors, the rear fenders, and the side of the rear bumper. 
     Given that the side mirror  2604  protrudes farther from the vehicle  101  than the side surfaces of the vehicle, the length of the water nozzles  2603  is different from the length of the water nozzles  2602 . In one embodiment, the length of the water nozzles  2603  used for washing the side mirror  2604  is shorter than the length of the water nozzles  2602  to provide clearance between the water nozzles  2603  and the side mirror  2604 . Otherwise, the water nozzles  2603  may impact the side mirror  2604  causing damage to the vehicle  101  and the water nozzles  2603 . 
     In one embodiment, water nozzles  2603  are configured to spray water at an angle  2606  with respect to reference line  2605  to increase wash performance of the side mirror  2604 . By spraying water at the angle  2606 , the water nozzles  2603  are capable of cleaning the inside portion of the side mirror  2604 . In one embodiment, the angle  2606  of the water nozzles  2603  used to wash the side mirror  2604  is 45-degrees. However, other angles may be used. In general, as the angle  2606  increases, the water injection distance increases and if the angle  2606  decreases, cleaning performance of the side mirror  2604  decreases. 
     In one embodiment, water nozzles  2602  and  2603  spray water such that the water temperature at the surface of the vehicle  101  is at a threshold temperature to improve wash performance. For example, the temperature of water sprayed by nozzles  2602  and  2603  is between 110 to 140 degrees Fahrenheit (F). In other embodiments, the temperature of water sprayed by nozzles  2602  and  2603  is at least 140 degrees F. The water temperatures at the surface of the vehicle  101  is based on various factors such as the water temperature prior to being sprayed by the water nozzles  2602  and  2603 , the nozzle diameter, and angle in which the water is sprayed (i.e., spray injection angle). 
     In one embodiment, the support structure  2605  is a structure that supports a water manifold  2601 . For example, support structure  2605 A supports water manifold  2601 A and support structure  2605 B supports water manifold  2601 B. The support structure  2605  may be mounted to the ground in one embodiment to prevent the support structure  2605  from falling. In one embodiment, the support structure  2605  may be rectangular in shape as shown in  FIGS.  26 A and  26 B  and may be made of metal such as aluminum, for example. However, other shapes and materials may be used for the support structure. 
     The plurality of fasteners  2607  fasten the water manifold  2601  to the support structure  2605 . For example, fasteners  2607 A fasten water manifold  2601 A to support structure  2605 A and fasteners  2607 B fasten water manifold  2601 B to support structure  2605 A. As shown in  FIG.  26   , the water manifold  2601  may be fastened to the support structure  2605  at multiple locations across the length of the water manifold  2601  to ensure that the water manifold  2601  is properly secured. 
     In one embodiment, each fastener  2607  is a clamp type fastener that wraps around the manifold  2601 . The fastener  2607  may have a hole in a center of the fastener  2607  and the water manifold  2601  is disposed within the hole. The fastener  2607  may be then fastened to the support structure  2605  using other types of fasteners such as screws and/or nuts and bolts thereby securing the water manifold  2601  to the support structure  2605 . 
     Collision Prevention Unit  1709   
       FIG.  27 A  illustrates a detailed view of a collision prevention unit  1709  according to one embodiment. The collision prevention unit  1709  includes a frame  2701  and a contact wheel  2704  in one embodiment. The collision prevention unit  1709  may have different components in other embodiments. 
     The frame  2701  includes a mounting plate  2703 C. The mounting plate  2703 C is used to mount the collision prevention unit  1109  to the support structure  2605  of the nozzle assemblies  1707  in one embodiment as shown in  FIG.  17   . 
     Referring back to  FIG.  27 A , the frame  2701  also includes extenders  2703 A and  2703 B. The extenders  2703  have first ends connected to the mounting plate  2703 C. The second ends of the extenders  2703  are separated from each other to form a recess between the second ends of the extenders  2703 . As shown in  FIG.  27 A , the extenders have a “L” shape in one embodiment. 
     The contact wheel  2704  is configured to contact the side surface of the vehicle  101  to prevent the water nozzles  2602  from being damaged as will be further described below. The contact wheel  2704  is configured to rotate across the surface of the vehicle  101  if the contact wheel  2704  contacts the side surface of the vehicle. To reduce damage to the surface of the vehicle  101  upon contact and as the contact wheel  2704  rolls on the side surface of the vehicle, the contact wheel  2704  is made of an elastic material such as rubber, for example. However, other materials may be used. As further described below, the contact wheel  2704  is constructed so that the water nozzles  2602  are not damaged due to contact with the side surfaces of the vehicle  101 . 
     As shown in  FIG.  27 A , the contact wheel  2704  is disposed in the recess formed between the second ends of the extenders  2703 . The contact wheel  2704  may be secured to the second extenders  2705  using a pin  2705  that is disposed between the second ends of the extenders  2703 . The contact wheel  2704  rotates around the pin  2705 . 
       FIGS.  27 B and  27 C  illustrate operation of the collision prevention units  1709  in one embodiment. As mentioned previously, collision prevention units  1709  prevent the water nozzles  2602  from contacting the side surface of the vehicle  101 .  FIG.  27 B  illustrates the initial wash operation of the second wash stage  105 . As described previously, during the initial wash operation, the base assembly  1705  is in contact with the tire  1801  of the vehicle. Since the base assembly  1705  is in contact with the tire, the base assembly  1705  cannot move underneath the vehicle  101 . Accordingly, the water nozzles  2602  cannot contact the side surface of the vehicle  101 . 
       FIG.  27 C  illustrates the wash operation of the second wash stage  105  where the base assembly  1705  is no longer in contact with the tire  1801 . Typically, the cylinder  1713  would lock thereby preventing the base assembly  1705  from moving inward toward the center of the second wash stage  105 . However, in the example shown in  FIG.  27 C , the cylinder  1713  has a malfunction resulting in failure of the lock operation that resulted in the base assembly  1705  going underneath the vehicle  101 . 
     As shown in  FIG.  27 C , the collision prevention unit  1709  is in contact with the side surface of the vehicle  101  when the base assembly  1705  is underneath the vehicle  101  thereby preventing the base assembly  1705  from further moving inward toward the center of the second wash stage  105 . If the base assemblies  1705  were to move further toward the center of the second wash stage  105 , the water nozzles  2602  would contact the side surface of the vehicle  101  thereby damaging the vehicle  101  and the water nozzles  2602 . However, given that the collision prevention unit  1709  is longer than the water nozzles  2602  and contacts the side surface of the vehicle  101  before the water nozzles  2602 , a distance  2705  is maintained between the end of the nozzles  2602  and the side surface of the vehicle  101 . 
     Overview of a Second Embodiment of the Second Wash Stage  105   
     Referring to  FIG.  28   , a perspective view of the second wash stage  105  of the car wash system  100  is shown according to a second embodiment. The second embodiment of the second wash stage  105  is similar to the first embodiment of the second wash stage  105  described with respect to  FIG.  17   . In the second embodiment of the second wash stage  105 , the second wash stage  105  includes a frame  1701 , a plurality of arms  1703 , a plurality of nozzle assemblies  1707 , intermediate stop circuit lines  1711 , and cylinders  1713  similar to the first embodiment of the second wash stage  105  described above. Thus, the description of the common components between the first embodiment and the second embodiment of the second wash stage  105  are omitted. 
     The second embodiment of the second wash stage  105  includes base assemblies  2801 . Base assemblies  2801  include a driver side base assembly  2801 A positioned at the left side of the second wash stage  105  and a passenger side base assembly  2801 B positioned at the right side of the second wash stage  105  in one embodiment. Similar to base assemblies  1705  in  FIG.  17   , base assemblies  2801  in  FIG.  27    according to the second embodiment adjust the width of the second wash stage  105 . However, the base assemblies  2801  in  FIG.  27    have a length that is longer than the base assemblies  1705  of the first embodiment of the second wash stage  105  in  FIG.  17   . For example, the length of the base assemblies  2801  according to the second embodiment is 163 inches whereas the length of the base assemblies  1705  according to the first embodiment is 79 inches. Thus, the length of the base assemblies  2801  is roughly double the length of the base assemblies  1705 . 
     The longer length of the base assemblies  2801  allows for the base assemblies  2801  to remain in contact with the tires  1801  of the vehicle  101  during the entire duration of the second wash stage  105 . Thus, in one embodiment the second embodiment of the second wash stage  105  lacks a collision prevention unit  1709  as the base assemblies  2801  prevent the water nozzles of the water assemblies  2801  from impacting the side surface of the vehicle  101  during the duration of the second wash stage  105 . However, the second embodiment of the second wash stage may still include an collision prevention unit  1709  in other embodiments. 
     Furthermore, although the second embodiment of the second wash stage  105  includes cylinders  1713 , the cylinders  1713  may lack a lock functionality. The cylinders  1713  may be used to dampen the vibration of the vehicle  101  upon impact with the base assemblies  2801 . However, the cylinders  1713  lack the lock functionality as there is no need to lock the width of the second wash stage  105  because the base assemblies  2801  are in contact with the tires  1801  of the vehicle  101  during the duration of the second wash stage  105  thereby providing such locking function instead. 
     Operation of the Second Embodiment of the Second Wash Stage  105   
       FIGS.  29 A to  29 C  illustrate operation of the second embodiment of the second wash stage  105  to wash side surfaces of the vehicle  101 .  FIG.  29 A  illustrates the adjustment operation during the second wash stage  105  operation. During the adjustment operation, the width of the second wash stage  105  is adjusted according to the width of the vehicle  101  in one embodiment. As shown in  FIG.  29 A , the front tires  1801  of the vehicle  101  contact the plurality of base assemblies  2801  as the vehicle  101  approaches the second wash stage  105 . As the vehicle  101  moves forward due the conveyer, the base assemblies  2801  are pushed outward away from the center of the second wash stage  105 B by being in contact with the front tires  1801  to set the width of the second wash stage  105  as shown in  FIG.  29 A . 
       FIG.  29 B  illustrates the wash operation of the second wash stage  105  in one embodiment. Once the width of the second wash stage  105  is adjusted according to the width of the vehicle  101 , the nozzle assemblies  1707  can begin washing the side surfaces of the vehicle  101 . The nozzle assemblies  1707  may wash the front portion (front fenders), center portion (e.g., doors), and rear portion (e.g., rear fenders) of the side surface of the vehicle  101  using water output by the nozzle assemblies  1707  or a combination of water and chemical (e.g., soap) output by the nozzle assemblies  1707 . If the nozzle assemblies  1707  output only water, the second wash stage  105  relies upon the chemical output by the chemical arches in the first wash stage  103  to aid in cleaning the vehicle  101 . 
     As shown in  FIG.  29 B , the base assemblies  2801  are in simultaneous contact with both the front tires  1801 A and the rear tires  1801 B while washing the center portion of the vehicle  101 . During the wash operation of the second embodiment of the second wash stage  105 , the base assemblies  2801 B are in contact with at least one of the front tires  1801 A or rear tires  1801 B due to the length of the base assemblies  2801 B. Thus, the width of the second wash stage  105  is maintained during the operation of the second wash stage  105 . Accordingly, the second embodiment of the second wash stage  105  does not require a lock function of the cylinders  1713  due to the base assemblies  2801  always being in contact with at least one of the front tires  1801 A or rear tires  1801 B or both, to maintain the adjusted width of the second wash stage  105 . In contrast, the first embodiment of the base assemblies  1705  are not in contact with any of the tires  1801  of the vehicle during at least a portion of the second wash operation and thus requires the lock function of the cylinders  1713  to maintain the width of the second wash stage  105 . Thus, operation of the cylinders  1713  is similar to the first embodiment of the second wash stage  105  described above except for the lack of needing to lock cylinders  1713 . 
       FIG.  29 C  illustrates the reset operation of the second embodiment of the second wash stage  105 . After the vehicle  101  has exited the second wash stage  105 , the width of the second wash stage  105  is reset to its initial position. In one embodiment, the width of the second wash stage  105  is reset using gravity and the weight of the base assemblies  2801  and arms  1703 . Gravity causes the base assemblies  2801  to move back to their initial position in one embodiment. After the second wash stage  105  is completed, the vehicle  101  may be dried by one or more fans or blowers (not shown). The fans generate wind that dry the surfaces of the vehicle  101  washed by the first wash stage  101  and the second wash stage  105 . 
     Base Assemblies  2801   
       FIGS.  30 A and  30 B  respectively illustrate detailed views of the components of base assemblies  2801 A and  2801 B according to one embodiment. The base assembly  2801 A includes a base structure  30001 A, a vehicle entry guide  3002 A, impact part  3003 A, impact part  3004 A, bearings  3005 A, and cylinder bracket  3005 A in one embodiment. Similarly, base assembly  2801 B includes a base structure  3001 B, a vehicle entry guide  3002 B, impact part  3003 B, impact part  3004 B, bearings  3005 B, and cylinder bracket  3005 B in one embodiment. 
     The functions performed by the base structure  3001 , the vehicle entry guide  3002 , the impact part  3003 , impact part  3004 , bearings  3005 , and the cylinder bracket  3005  are similar to the functions performed by the base structure  2301 , the vehicle entry guide  2302 , impact part  2303 A, impact part  2304 , bearings  2305 , and cylinder bracket  2305  as described above. Thus, the detailed description of the components of the base assemblies  2801 A and  2801 B are omitted as the detailed description of the components of the base assemblies  1705 A and  1705 B are applicable to the components of the base assemblies  2801 A and  2801 B. 
     Due to the increased length of the base assemblies  2801 A and  2801 B compared to base assemblies  1705 A and  1705 B, the bearings  3005  are not positioned at the ends of the base structures  3001  as in the first embodiment of the base assemblies  1705 . Rather, the bearings  3005  are positioned closer to the center of the base structure  2301  as shown in  FIG.  30   . 
       FIGS.  31 A and  31 B  respectively illustrate plan views of the base assembly  2801 A and base assembly  2801 B according to one embodiment. Specifically,  FIGS.  31 A and  31 B  respectively illustrate hinge points  3101 A and  3103 A of base assembly  2801 A and hinge points  3101 B and  3103 B of base assembly  2801 B. Hinge points  3101  are representative of the upper pair of bearings  3005  and hinge points  3103  are representative of the lower pair of bearings  3005  positioned in one embodiment. Due to the longer length of the base assemblies  2801 , each base assembly  2801  includes two or more hinge points  3103  in one embodiment. Having at least two hinge points  3103  prevents the base assemblies  2801  from sagging. 
     As shown in  FIGS.  31 A and  31 B , the hinge points  3101  and  3103  are misaligned in one embodiment. That is, the hinge points  3101  and  3103  are misaligned in both the horizontal and vertical directions. Due to the misalignment, hinge points  3101  and  3103  are offset from each other in both the horizontal and vertical directions. 
     In one embodiment, the hinge points  3101  and  3103  are angled with respect to an edge of the base assembly  3105 . For example, hinge point  3101 A and  3103 A are angled with respect to the edge  3105 A at an angle of 45 degrees in one embodiment, but other angles may be used. Similarly, hinge point  3101 B and  3103 B are angled with respect to the edge  3105 B at an angle of 45 degrees in one embodiment. Angling the hinge points  3101  and  3103  mitigates the impact of the vehicle  101  upon entry and reduces tilting of the base assembly  2801 . In one embodiment, the distance  3102  (e.g.,  3102 A and  3102 B) between center points of hinge point  3101  and  3103  is a threshold distance such as at least 20.9 inches. However, other distances may be used. If the distance between the center points of hinge point  3101  and  3103  is less than the threshold distance, the base assembly  2801  shakes upon impact with the tires  1801  of the vehicle  101 . Having the hinge points  3101  and  3103  separated by the threshold distance reduces shaking upon impact between the base assembly  2801  and the tires  1801 . 
     Controller  109   
     In one embodiment, the controller  109  independently controls the first wash stage  103  and the second wash stage  105  to wash the vehicle  101 .  FIG.  32    illustrates a detailed view of the controller  109  according to one embodiment. 
     As shown in  FIG.  32   , the controller  109  includes a first wash stage module  3201  and a second wash stage module  3203  in one embodiment. Generally, the first wash stage module  3201  controls operation of the first wash stage  103  to wash the front, top, and rear surfaces of the vehicle  101 . In contrast, the second wash stage module  3203  controls operation of the second wash stage  105  to wash the side surfaces of the vehicle  101 . The control of the first wash stage  101  and the second wash stage  102  by the first wash stage module  3201  and the second wash stage  3203 , respectively, are separate and independent from each other. The controller  109  may include other modules than those shown in  FIG.  32    in other embodiments. 
     The first wash stage module  3201  includes a contour profile module  3205 , a water module  3209 , and an adjustment module  3211  according to one embodiment. However, the first wash stage module  3201  may include other modules in other embodiments. 
     The contour profile module  3205  determines the contour profile for each vehicle  101  that is washed by the first wash stage  101 . As mentioned previously, the contour profile of a vehicle  101  includes a plurality of height points of the vehicle  101  that are measured along the length of the vehicle  101  using the optical sensor  301 . The contour profile module  3205  determines the contour of the vehicle  101  based on sensing data received from the optical sensor  301 . The sensing data is received from the optical sensor  301  and the contour profile module  3205  determines the height points along the length of the vehicle  101  based on the sensing data to generate the contour profile for the vehicle  101 . 
     Water module  3209  controls the operation of the wash unit  306  in one embodiment. The water module  3209  interdependently controls when to activate (e.g., turn on) or deactivate (e.g., turn off) the nozzles  1305  on the front manifold  306 A and when to activate or deactivate the nozzles  1307  on the rear manifold  306 B in one embodiment. 
     For example, the water module  3209  interdependently controls the operation of the nozzles  1305  and  1307  by turning on the nozzles  1305  on the front manifold  306 A after a predetermined amount of time from when the vehicle  101  first crosses the optical sensor  301 , and determines when to turn off the nozzles  1305  on the front manifold  306 A and turn on the nozzles  1307  on the rear manifold  306 A according to the contour profile of each vehicle  101  being washed by the front wash stage  103 . The water module  3209  can determine the timing of the turn on and turn off operation of the nozzles  1305  and  1307  based on when the rear surface of the vehicle needs to be washed according to the contour profile and accordingly turns off the nozzles  1305  on the front manifold  306 A and turns on the nozzles  1307  on the rear manifold  306 A. 
     The adjustment module  3211  adjusts the position of the telescoping unit  304  according to the contour profile of the vehicle  101 . For each height point included in the contour profile of a vehicle, the adjustment module  3211  provides a signal to the motor  305  that indicates how much rotation of the motor  305  is required to raise or lower the telescoping unit  304  based on the height. In one embodiment, a lookup table is stored in memory that maps different heights to an amount of vertical movement of the telescoping unit  304  that is needed to achieve the desired height. The amount of vertical movement is translated into a predetermined number of turns of the motor  304  that is required to achieve the desired height. 
     The second wash stage module  3203  includes a water module  3215  and a lock module  3219  according to one embodiment. However, the second wash stage module  3203  may include different modules than shown in  FIG.  32    in other embodiments. 
     Water module  3215  controls the operation of the nozzle assemblies wash unit  1707  in one embodiment. The water module  3215  controls when to activate (e.g., turn on) or deactivate (e.g., turn off) the nozzles  2602 ,  2603  included in the wash unit  1707 . 
     The water module  3215  may turn on the nozzles  2602 ,  2603  responsive to determining the width of the second wash stage  105  changing due to the vehicle  101  impacting the base assembly  1705 ,  2801  in one example. The water module  3215  may subsequently turn off the nozzles  2602 ,  2603  after detecting that the width of the second wash stag  105  is reset to its initial position. 
     In one embodiment, an angle sensor may be mounted on the arms  1703  of the second wash stage  105 . The water module  3215  may receive a signal from the angle sensor indicative of the angle of the arms  1703 . Based on the signal, the water module  3215  may determine the change of the width of the second wash stage  105  when the angle of the arms  1703  changes. Accordingly, the water module  3215  may turn on the nozzles  2602 ,  2603  upon detection that the width of the second wash stage  105  is changed from its initial position and may turn off the nozzles  2602 ,  2603  upon detection that the width of the second wash stage is returned back to its initial position. 
     The lock module  3219  is configured to lock the length of the cylinders  1713  to hold the width of the second wash stage  105 . The lock module  3219  may receive a signal from the angle sensor that is mounted on the arms  1703  of the second wash stage  105 . The lock module  3219  monitors the angle of the arms  1703  to determine that the arms  1703  are at a constant angle that is greater than the angle that corresponds to the initial position of arms  1703  for a threshold amount of time (e.g., 2 seconds). The angle of the arms  1703  being constant for the threshold amount of time signifies that the width of the second wash stage  105  is set and thereby locks the cylinders  1713 . 
     In one embodiment, the lock module  3219  is configured to unlock the cylinders  1713  responsive to determining that the vehicle  101  has exited the second wash stage  105 . The lock module  3219  may determine when to unlock the cylinders  1713  due to knowing the position of the conveyer  107  and thereby the position of the vehicle  101  at all times. 
     Although a single controller  109  is shown in  FIGS.  1  and  32   , the functionality of the controller described herein may be divided among any number of controllers. For example, the car wash  100  may include a controller including the first wash stage module  3201  and a separate, independent controller that includes the second wash stage module  3203 . Alternatively, the controller  109  may be a single controller. Thus, the embodiments herein may use a single controller or multiple controllers to control the first wash stage  103  and the second wash stage  105 . 
     Computer Hardware Components 
       FIG.  33    is a diagram illustrating a computer system  3300  upon which embodiments described herein may be implemented within the car wash system  100 . For example, in the context of  FIG.  1   , the controller  109  may be implemented using a computer system such as described by  FIG.  33   . The controller  109  may also be implemented using a combination of multiple computer systems as described by  FIG.  33   . 
     In one implementation, the controller  109  includes processing resources  3301 , main memory  3303 , read only memory (ROM)  3305 , storage device  3307 , and a communication interface  3309 . The controller  109  includes at least one processor  3301  for processing information and a main memory  303 , such as a random-access memory (RAM) or other dynamic storage device, for storing information and instructions to be executed by the processor  3301 . Main memory  3303  also may be used for storing temporary variables or other intermediate information during execution of instructions to be executed by processor  3301 . Controller  109  may also include ROM  3305  or other static storage device for storing static information and instructions for processor  801 . The storage device  3307 , such as a magnetic disk or optical disk or solid-state memory device, is provided for storing information and instructions. In one embodiment, the contour profiles of vehicles  101  are stored in one of the main memory  3303 , ROM  3305 , or the storage device  3307  or a combination thereof. 
     The communication interface  3309  can enable the controller  109  to communicate with other computer systems through use of a communication link (wireless or wireline). The controller  109  can optionally include a display device  3311 , such as a cathode ray tube (CRT), an LCD monitor, an LED monitor, a TFT display or a television set, for example, for displaying graphics and information to a user. An input mechanism  3313 , such as a keyboard that includes alphanumeric keys and other keys, can optionally be coupled to the computer system  3300  for communicating information and command selections to processor  3301 . Other non-limiting, illustrative examples of input mechanisms  3313  include a mouse, a trackball, touch-sensitive screen, or cursor direction keys for communicating direction information and command selections to processor  3301  and for controlling cursor movement on display device  811 . 
     Examples described herein are related to the use of the controller  109  for implementing the techniques described herein. According to one embodiment, those techniques are performed by the controller  109  in response to processor  3301  executing one or more sequences of one or more instructions contained in main memory  3303 . Such instructions may be read into main memory  3303  from another machine-readable medium, such as storage device  3307 . Execution of the sequences of instructions contained in main memory  3303  causes processor  3301  to perform the process steps described herein. In alternative implementations, hard-wired circuitry may be used in place of or in combination with software instructions to implement examples described herein. The various modules shown in  FIG.  32    may be software modules stored in one of the main memory  3303 , ROM  3305 , or the storage device  3307  or a combination thereof for execution by the processor  3301 , may be hardware modules, or may be a combination of hardware and software. Thus, the examples described are not limited to any specific combination of hardware circuitry and software. 
     Reference in the specification to “one embodiment” or to “an embodiment” means that a particular feature, structure, or characteristic is included in at least one embodiment of the disclosure. The appearances of the phrase “in one embodiment” or “a preferred embodiment” in various places in the specification are not necessarily referring to the same embodiment. 
     In the present disclosure terms such as “first,” “second,” “A,” “B″” bay be used herein to describe elements of the present invention. Each of these terms is not used to define essence, order, sequence, or number of elements etc., but is used merely to distinguish the corresponding element from other elements. For example, the telescoping unit  304  includes a plurality of rail stages  801  where the rail stages include rail stage  801 A,  801 B,  801 C, and  801 D. 
     Certain aspects disclosed herein include process steps and instructions described herein in the form of a method. It should be noted that the process steps and instructions described herein can be embodied in software, firmware or hardware, and when embodied in software, can be downloaded to reside on and be operated from different platforms used by a variety of operating systems. Furthermore, it has also proven convenient at times, to refer to arrangements of operations as modules, without loss of generality. The described operations and their associated modules may be embodied in software, firmware, hardware, or any combinations thereof. 
     The embodiments discussed above also relates to an apparatus for performing the operations herein. This apparatus may be specially constructed for the required purposes, or it may comprise a general-purpose computer selectively activated or reconfigured by a computer program stored in the computer. Such a computer program may be stored in a non-transitory computer readable storage medium, such as, but is not limited to, any type of disk including floppy disks, optical disks, CD-ROMs, magnetic-optical disks, read-only memories (ROMs), random access memories (RAMs), EPROMs, EEPROMs, magnetic or optical cards, application specific integrated circuits (ASICs), or any type of media suitable for storing electronic instructions, and each coupled to a computer system bus. Furthermore, the computers referred to in the specification may include a single processor or may be architectures employing multiple processor designs for increased computing capability. 
     The methods and displays presented herein are not inherently related to any particular computer or other apparatus. Various general-purpose systems may also be used with programs in accordance with the teachings herein, or it may prove convenient to construct more specialized apparatus to perform the required method steps. The required structure for a variety of these systems will appear from the description below. In addition, the embodiments are not described with reference to any particular programming language. It will be appreciated that a variety of programming languages may be used to implement the teachings described herein, and any references below to specific languages are provided for disclosure of enablement and best mode. 
     While the disclosure has been particularly shown and described with reference to a preferred embodiment and several alternate embodiments, it will be understood by persons skilled in the relevant art that various changes in form and details can be made therein without departing from the spirit and scope of the invention.