Abstract:
An apparatus for a tactile surface in a pedestrian walkway aiding navigation of the walkway by visually impaired persons. The apparatus includes a tactile tile segment with a base and a pair of parallel, raised ribs. In one embodiment, the tile segment is a resilient material. Between the parallel ribs is a flat area or guideway configured to receive a tip of a cane for guiding a cane user in a direction parallel to the ribs. The tile segments are configured to butt together at their distal ends to form an extended surface. In one embodiment, a clamping strip is positioned with a portion over a longitudinal edge of the tile segment to prevent the lifting of the edge of the strip from vehicular traffic. The clamping strip is configured to attach to a roadway and is made of a durable, rigid material.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit of U.S. Provisional Application No. 60/862,423, filed Oct. 20, 2006. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
       [0002]     Not Applicable  
       BACKGROUND OF THE INVENTION  
       [0003]     1. Field of Invention  
         [0004]     This invention pertains to a tactile surface disposed on a pedestrian walkway to enable passage by blind or partially-sighted persons. More particularly, this invention pertains to a series of parallel raised ribs positioned alongside or on the walkway.  
         [0005]     2. Description of the Related Art  
         [0006]     Many visually impaired persons, that is, blind or partially sighted persons, have developed skills necessary to navigate in public. These skills include using their senses, such as touch and hearing, and various aids, such as canes and guide dogs. In many cases, these skills are sufficient to allow a visually impaired person to navigate walkways and streets.  
         [0007]     Attempts have been made to provide secondary aids to assist visually impaired persons in navigating in public. For example, U.S. Pat. No. 5,936,528, issued to Kobayashi, et al., on Aug. 10, 1999, titled “Visually handicapped person guidance and support” discloses a portable scanner incorporated into a cane. The scanner is responsive to a resonance label that is positioned adjacent a passage, stair, aisle floor, wall surface, or Braille block.  
         [0008]     U.S. Pat. No. 6,867,697, issued to Nanayakkara, et al., on Mar. 15, 2005, titled “System for guiding the visually handicapped,” discloses another navigation aid that is incorporated into a walkway and is sensed by a person wearing special shoes or carrying a special cane. A continuous electrical conductor is embedded within a walkway. A detector sensitive to the embedded conductor is incorporated into a shoe or a cane. The detector provides information to a person when the detector is proximate the embedded conductor.  
         [0009]     U.S. Pat. Nos. 6,992,592 and 7,199,725, both issued to Gilfix, et al., on Jan. 31, 2006, and Apr. 3, 2007, respectively, both titled “Radio frequency identification aiding the visually impaired with sound skins,” disclose electronic travel aids that are responsive to radio frequency identification (RFID) tags associated with objects that a visually impaired person would encounter. The electronic travel aid is a hand held device that provides information via a speaker and a tactile display when the travel aid receives data from the RFID.  
         [0010]     The above-identified aids require that the visually impaired person carry a special device other than would normally be carried by such a person. There is a need for a passive travel aid that readily provides information to a visually impaired person without requiring the person to carry or wear special equipment. There is a need for such a passive travel aid to be available to everyone. There is a need for such a passive travel aid to be readily deployed at locations where such a travel aid would provide useful navigational information. There is a need for a travel aid that is readily discernable from adjacent environmental features.  
       BRIEF SUMMARY OF THE INVENTION  
       [0011]     According to one embodiment of the present invention, a tactile surface for a walkway is provided by a pair of parallel raised ribs that run parallel to the walkway. The raised ribs are elongated ridges that allow detection of the walkway direction directly when a person contacts the raised ribs with either footwear or a cane. The pair of raised ribs are positioned side-by-side with sufficient room for a cane tip to be positioned in a guideway between the ribs. A person is guided along the tactile surface by placing the cane tip between the pair of raised ribs and walking in the direction indicated by the pair of ribs. In one embodiment, one or both of the ribs have a short break that indicates a waypoint or a stopping point. In various embodiments, the raised ribs are positioned on one side and/or the other of the walkway or down the center of the walkway.  
         [0012]     The ribs are spaced apart and have a height that allows for tactile feedback of the guideway, but does not present a tripping hazard. In one such embodiment, the height to separation ratio is approximately 1:8. The raised ribs avoid creating a tripping hazard by having a rounded surface with no edges or corners that would allow an object, such as a shoe or other footwear, to catch on the raised rib.  
         [0013]     In one embodiment, the tactile surface is positioned on a roadway between opposing sidewalks. Adjacent the ends of the tactile surface on the sidewalks are tiles that indicate the presence of the tactile surface to blind or partially-sighted persons. In various embodiments, the tiles provide tactile and/or audible indication to pedestrians, without creating a tripping hazard.  
         [0014]     In one embodiment, a tile segment includes the pair of raised ribs protruding from a base. The base is adapted to be securely attached to a surface. In one embodiment, the ends of the pair of raised ribs on the tile segment are flush with the ends of the base, thereby allowing one segment to be butted against another segment to form a pair of continuous raised ribs. In one such embodiment, the ends of the tile segments are angled, that is, the ends are not perpendicular to the base, but the surface of the end is at an angle relative to the base such that the ends of two tile segments have a larger surface area for an adhesive to be disposed when butt joining the two tile segments. In other embodiments, one or both ends of the raised ribs are rounded, which presents a smooth surface that avoids tripping hazards. The rounded ends are positioned at the start or end of the guideway. In another embodiment, the rounded ends are positioned between the ends of the guideway to indicate a waypoint or stopping point by the cane tip encountering the opening in the raised rib formed by a pair of rounded ends facing each other. In such an embodiment, the opening also allows for drainage of water and other fluids that would otherwise collect between the raised ribs.  
         [0015]     In one embodiment, the tile segments are for placement alongside a pedestrian cross-walk on a roadway. A clamping strip, or clamp, is positioned on the on-coming traffic side of the tile segments. The clamping strip has one side that forms a smooth joint with the roadway and an opposite side that pushes the base against the roadway. The clamping strip prevents the tile segments from being peeled or forced off the roadway by an object pushing against the tile segments. For example, a snow plow striking the clamping strip will be forced up and over the tile segments. 
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0016]     The above-mentioned features of the invention will become more clearly understood from the following detailed description of the invention read together with the drawings in which:  
         [0017]      FIG. 1  is a partial perspective view of an intersection showing one embodiment of the tactile surface;  
         [0018]      FIG. 2  is a perspective view of a person using one embodiment of the tactile surface;  
         [0019]      FIG. 3  is a plan view of one embodiment of a tactile tile segment;  
         [0020]      FIG. 4  is an end view of the embodiment of the tactile tile segment of  FIG. 3 ;  
         [0021]      FIG. 5  is a top view of a series of tile segments for another embodiment of a tactile surface that makes a right-angle turn;  
         [0022]      FIG. 6  is a partial side view of one embodiment of a tile segment showing a rounded end;  
         [0023]      FIG. 7  is a partial side view of another embodiment of a tile segment showing a flush end;  
         [0024]      FIG. 8  is a partial side view of another embodiment of a pair of tile segments showing angled ends;  
         [0025]      FIG. 9  is a partial top view of one embodiment of a clamping strip securing a tile segment; and  
         [0026]      FIG. 10  is a cross-sectional view of the clamping strip and tile segment shown in  FIG. 9 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0027]     An apparatus for a tactile surface  100  disposed on or along a pedestrian walkway  104  is disclosed. Visually impaired persons, such as blind or partially sighted persons, often rely upon tactile sensations in order to navigate while walking. Even for a sighted person, crossing a street is oftentimes hazardous. Enabling blind or partially sighted persons to navigate a street crossing in a straight-forward manner without conscious effort allows those persons to devote their senses to detecting the various dangers and hazards present on a roadway.  
         [0028]      FIG. 1  illustrates a partial perspective view of a road or street intersection  102  showing a tactile surface  100  located on each side of a pedestrian cross-walk  104 . An intersection  102  includes a stop line  106  on one side of the center line  116  in a roadway  114 . Between the stop line  106  and the center of the intersection  102  are a pair of tactile surfaces  100  and the pedestrian cross-walk  104 . In various embodiments, the tactile surface  100  and the pedestrian cross-walk  104  are positioned side-by-side, left to right or vice versa, overlapping each other, or one overlaying the other. The pedestrian cross-walk  104 , the stop line  106 , and the roadway center line  116  are typically painted onto the surface of the roadway  114 . It is common for the pedestrian cross-walk  104  to be a series of parallel white bars oriented perpendicular to the direction of pedestrian traffic on the roadway  114 . Pedestrian cross-walks  104  are also known to be a pair of parallel white lines extending between the sidewalks  108  and delineating the path for pedestrians between the lines. In one embodiment, the tactile surfaces  100  are white and delineate the borders of the cross-walk  104 .  
         [0029]     On the sides of the roadway  114  are sidewalks  108  that typically have a curb separating the raised surface of the sidewalk  108  from the surface of the roadway  114 . The sidewalks  108  are defined by the curb adjacent the roadway  114  and buildings  110  or other structures that are parallel to or set back from the roadway  114 .  
         [0030]     A pedestrian on one sidewalk  108 , who wishes to cross a roadway  114  to the other sidewalk  108 ′, stands on the sidewalk  108  until the traffic conditions on the roadway  114  permit the pedestrian to cross the roadway  114  on the pedestrian cross-walk  104 . A sighted pedestrian typically has no difficulty in seeing the markings defining the cross-walk  104 . Likewise, a sighted pedestrian has no problem positioning themselves on the sidewalk  108  adjacent to the cross-walk  104 .  
         [0031]     A blind or partially sighted person  212  walking along the sidewalk  108  relies upon various cues to determine the correct path to follow. Tapping a cane  216  provides such a person  212  with feedback indicating the location of buildings  110  and intersections  102 . A crossing notice tile  112  on the surface of the sidewalk  108  adjacent the tactile surface  100  indicates to a blind or partially sighted person  212  where a tactile surface  100  for crossing the roadway  114  is located. After determining the location of the tactile surface  100 , such a person  212  uses the tactile surface  100  to guide themselves across the roadway  114  in a sure and expeditious manner.  
         [0032]     The crossing notice tile  112  is a tile embedded in the sidewalk  112  that provides an indication to a person  212  of the presence of the tactile surface  100 . The notice tile  112  has features that are detectable by a blind or partially sighted person  212 . In one embodiment, the notice tile  112  includes upward facing protrusions that are detectable by the person  212 . In another embodiment, the notice tile  112  provides an audible response to the person  212  when tapped with a cane  216 . After being detected, the crossing notice tile  112  informs the person  212  of the location of the tactile surface  100 .  
         [0033]     Audible signals are used for guiding blind or partially sighted persons  212  across roadways  114 . The audible signals provide direction and distance information to the person  212  because the location of the audible signal is detected by moving the head and the intensity, which indicates the relative distance, is discerned by the ears. Roadways  114  carry traffic, which generates background noise. The background noise competes with the audible signals. It is not uncommon for the intensity of the audible signals to be drowned out by the background signals or for others to complain that the audible signals are too loud if the intensity of the signals are adjusted to overcome the background noise. The surface  100  allows a person  212  to be guided across such a roadway  114  without the use of an audible signal.  
         [0034]      FIG. 2  illustrates a perspective view of a person  212  using one embodiment of the tactile surface  100 . The illustrated person  212  holds a cane  216  that provides tactile feedback to the person  212 . By tapping the cane  216  on a surface and listening for the echoes, a person  212  often obtains information about their surroundings. Also, the cane  216  provides tactile feedback to the person  212  regarding the type and texture of the surface surrounding the person  212 , in particular, the surface immediately in front of the person  212 . It is common for such a person  212  to swing the cane  216  from side-to-side or even back-and-forth in a direction  218  in-line with the direction of travel.  
         [0035]     The tactile surface  100  is positioned alongside or on a walkway or path. The tactile surface  100  includes a series of segments  202  positioned adjacent each other. Each segment  202  includes a pair of raised ribs  204 . Each raised rib  204  is a rounded elongated ridge extending above the surface of the base  304  of the segment  202 . The person  212  holds a cane  216  with the tip  220  positioned in the area, or guideway,  206  between the raised ribs  204 . The cane tip  220  provides tactile feedback to the person  212  of the surface direction  218 , thereby allowing the person  212  to move in the forward direction  214 .  
         [0036]     In another embodiment, the tactile surface  100  includes segments  202  that have various numbers of raised ribs  204 . In still another embodiment, the tactile surface  100  has a base  304  with a top surface flush with the surface of the roadway  114 . Various such embodiments include raised ribs  204  protruding either from a material deposited into a channel in the roadway  114  or from the material of the roadway  114  itself. For example, in a roadway  114  made of a concrete material, the tactile surface  100  includes raised ribs  204  of the same concrete material as the roadway  114  and are fabricated as part of the roadway  114 .  
         [0037]     In the illustration, the cane tip  220  is approaching a gap  210  in the raised ribs  204 . The gap  210  is formed at a joint, or connection,  208  between two tile segments  202 . When the person  212  senses the gap  210  with the cane tip  220 , the person  212  is put on notice of a specific location on the tactile surface  100 . The specific location indicated by the gap  210  includes stopping points, warnings of upcoming turns, or other information.  
         [0038]     The illustrated embodiment of the tactile surface  100  also provides notice to a person  212  as a warning indication. The tactile tile segments  202  are un-obtrusive and suitable for use in many environments. When a person  212 , sighted or not, steps on the tactile tile segments  202 , the person  212  is immediately put on notice of the direction and boundary of a walkway  104 .  
         [0039]      FIG. 3  illustrates a plan view of one embodiment of a tactile tile segment  202 -A.  FIG. 4  illustrates an end view of the embodiment of the tactile tile segment  202 -A shown in  FIG. 3 . The tile segment  202 -A includes a base  304  that is substantially rectangular. The base  304  has a thickness sufficient to support and secure the raised ribs  204 -A. The length of the segment  202 -A, that is, the length of the base measured along the longitudinal axis of the raised ribs  204 -A, is determined by the desired length of the tactile surface  100 . In one embodiment, the length is 24 inches. The length of the raised ribs  204 -A is slightly less than the length of the base  206  because the ends  302 -A of the raised ribs  204 -A are rounded to avoid creating a tripping hazard.  
         [0040]     In the illustrated embodiment, the base  304  includes an upper bevel  412 . In one embodiment, the bevel  412  extends to the bottom of the base  304 . In another embodiment, there is no bevel  412  on the base  304 . In one embodiment, the segment  202 -A is formed of a polyurethane casting resin with the illustrated shape and configuration. In other embodiments, the raised ribs  204 -A are formed of the material used for the roadway  114  or other surface from which the raised ribs  204 -A protrude.  
         [0041]     In the illustrated embodiment, an area, or guideway,  206  is defined between raised ribs  204 -A. The centers of the raised ribs  204 -A are separated by a first distance  402  and the center of the raised ribs  204 -A are a second distance  404  from the edge of the segment  202 -A. To maintain even spacing of the raised ribs  204 -A when multiple segments  202 -A are joined by butting them together, the second distance  404  is one-half the first distance  402 . In one embodiment, the separation, or first, distance  402  is approximately two inches.  
         [0042]     The raised ribs  204 -A are elongated ridges with a rounded surface, that is, each rib  204  has a partial cylindrical shape. Each raised rib  204 -A has a width  406  and a height  408 . The width  406  and the height  408 , along with the separation distance  402 , are dimensioned to avoid creating a tripping hazard to pedestrians while still being of a size that enables tactile feedback to a blind or partially sighted person  212 . In one embodiment, the dimensions found to provide tactile feedback without causing a tripping hazed were a width  406  of 0.75 inches and a height  408  of 0.25 inches with a separation distance  402  of two inches. Such dimensions result in a height  408  to separation  402  ratio of 1:8.  
         [0043]     The spacing  402  and the dimensions  406 ,  408  of the raised ribs  204  allow a person  212  to detect the raised ribs  204 -A with their feet. If the person  212  is barefoot or has footwear with thin soles, the person  212  detects directly the raised ribs  204 -A under the foot when the foot are in contact with the raised ribs  204 -A. Additionally, the person  212  detects indirectly the raised ribs  204 -A by the interaction of the foot with the raised ribs  204 -A and base  304 , even when the person  502  has footwear with thick soles. Such interaction includes tilting of the foot from side-to-side and provides information as to the direction  218  of the tactile surface  100 . Accordingly, the dimensions and configuration of the raised ribs  204 -A on the tactile surface  100  allows a blind or partially sighted person  212  to follow the tactile surface  100  and stay on the walkway  104 .  
         [0044]      FIG. 5  illustrates a top view of a series of tile segments  202  for an embodiment of a tactile surface  100  that makes a right-angle turn  508 . The illustrated embodiment of the tactile surface  100  includes a series of tile segments  202  positioned end-to-end at joints  210 . The tile segments  202  include a tile segment  202 -A having rounded ends  306 -A on each end of the raised ribs  204 -A, a tile segment  202 -B having a pair of rounded ends  306 -A on one end of the raised ribs  204 -A, tile segments  202 -C,  202 -D having square-cut ends  306 -B on one end of the raised ribs  204 -A and with the opposite end of the tile segment  202 -C having a corner end (miter)  604 -A,  604 -B configured to form one-half of a turn in the tactile surface  100 -B, and a tile segment  202 -E having square-cut ends  306 -B on each end of the raised ribs  204 -A. In other embodiments, the tile segments  202  have other combinations of ends  306  and shapes of the base  206  to accommodate the requirements of the tactile surface  100 . In one embodiment, the tile segments  202  are glued or adhered to a surface, such as the roadway  114 . In one such embodiment, the tile segments  202  are set inside an opening or channel in the surface such that the top of the base  304  is flush with the surface. In one such embodiment, the base  206  does not have a bevel  412 .  
         [0045]     The illustrated embodiment of the tactile surface  100  includes a gap  210  in the raised ribs  204 -A. Gaps  210  in the raised ribs  204 -A are defined by in-line pairs of ribs  204 -A with rounded ends  302 -A. The gap  210  serves two purposes. First, the gaps  210  allow water and other fluids to escape the area  206  between the raised ribs  204 . Second, the gap  210  marks a location on the tactile surface  100  that a person  212  detects with a cane  216  and is used to indicate a location along the tactile surface  100 .  
         [0046]     The illustrated embodiment shows a gap  210 -A positioned on one side of the guideway  206 . The gap  210 -A is defined by a break in one of the raised ribs  204  extending along tile segments  202 -A,  202 -B. The break, or gap,  210 -A is bounded by rounded ends  302 -A. By positioning the gap  210 -A on only one side of the guideway  206 , a visually impaired person  212  is provided tactile information that is specific. For example, the gap  210 -A is positioned on the same side as the upcoming turn  508  for a person  212  approaching the turn  508 , thereby warning the person  212  of the turn  508 .  
         [0047]      FIG. 6  illustrates a partial side view of one embodiment of a tile segment  202 -A showing a rounded end  302 -A. The illustration applies equally to any tile segment  202  that includes a raised rib  204  with a rounded end  302 -A. The raised rib  204 -A has an end  302 -A with a rounded profile when viewed from the end (shown in  FIG. 4 ) and a rounded profile when viewed from the side (shown in  FIG. 6 ). The rounded end  302 -A is used to terminate the raised ribs  204 -A, such as at the start and finish of the tactile surface  100 , and to bound the gaps  210  between the ends of the raised ribs  204 -A. The rounded ends  302 -A provide a smooth end  302  for the raised ribs  204  and avoids creating a tripping hazard or otherwise presenting a surface or edge that will catch an object, such as an article of clothing, footwear, or other object that is dragged across the tile segment  202 .  
         [0048]      FIG. 7  illustrates a partial side view of another embodiment of a tile segment  202 -E showing a flush, or square-cut, end  306 -B. The illustration applies equally to any tile segment  202  that includes a raised rib  204  with a square-cut end  302 -B. The square-cut end  302 -B of the raised rib  204 -E is flush with the adjacent end of the base  304 . Tile segments  202 -B,  202 -C,  202 -D,  202 -E that are butted together at a joint  208  without a gap  210  have a continuous section of raised ribs  204 -E. In the illustrated embodiment, the joint  208  is a butt joint with the ends  302 -B having a surface perpendicular to the top or bottom of the base  304 . Two tile segments  202  are joined with an adhesive disposed between the bases  304 , and for the tile segments  202 -B,  202 -C,  202 -D,  202 -E that are butted together at a joint  208  without a gap  210 , the joint  208  includes an adhesive between the square-cut ends  302 -B.  
         [0049]      FIG. 8  illustrates a partial side view of another embodiment of a pair of tile segments  202 -E′ showing angled, or sloping, ends  306 -C to form a variation of a butt joint typically called a scarf joint. The illustration applies equally to any tile segment  202  that includes a raised rib  204  with an angle-cut end  302 -C. The angle-cut end  302 -C of the raised rib  204 -E′ is flush with the adjacent end of the base  304 . That is, the surface of the angle-cut end  302 -C continues on the same plane as the surface of the adjacent end of the base  304 .  
         [0050]     Tile segments  202 -B,  202 -C,  202 -D,  202 -E that are joined together at a joint  208  without a gap  210  have a continuous section of raised ribs  204 -E. In one embodiment, the joint  208  has the ends  302 -C being at an angle relative to the base  304 . Two tile segments  202  are joined with an adhesive disposed between the bases  304 , and for the tile segments  202 -B,  202 -C,  202 -D,  202 -E that are joined together at a joint  208  without a gap  210 , the joint  208  includes an adhesive between the angle-cut ends  302 -C. The joint  208  formed from mating two angle-cut ends  302 -C,  302 -C′ allows for a greater surface area of the joint  208  to be joined with an adhesive than with the square-cut ends  302 -B, resulting in a strong joint  208 . The angle-cut ends  302 -C also present an angled edge if there is a slight misalignment in joining two segments  202 , thereby aiding the passage of a cane tip  216  past the misalignment.  
         [0051]      FIG. 9  illustrates a partial top view of one embodiment of a clamping strip  902  securing a tile segment  202 .  FIG. 10  illustrates a cross-sectional view of the clamping strip  902  and tile segment  202  shown in  FIG. 11 . The tile segments  202  of the surface  100  when used on a roadway  114  present a side to oncoming traffic. A clamping strip  902  clamps one or both sides of the tile segments  202  to the roadway  114  or other surface, thereby protecting the side, or edge, of the tile segment  202 .  
         [0052]     The clamping strip  902  includes an outboard end  1004  that contacts the roadway  114  and an inboard end  1002  with a surface that contacts the top of the base  206  outboard of the raised rib  204 . In various embodiments, the outboard end  1004  is tapered toward the tile segment or slanted profile away from the tile segment  202 . The profile of the outboard end  1004  aids in the smooth transition of foreign objects from the roadway  114  to the tile segment  202 , thereby aiding in preventing the foreign objects from catching on the side edge of the tile segment  202 , which could cause the tile segment  202  from being separated from the roadway  114  or other surface. Examples of foreign objects include plows or objects hanging from vehicles that either drag on or are carried just above the surface of the roadway  114 .  
         [0053]     The illustrated embodiment of the clamping strip  902  includes a series of openings  904  along the length of the clamping strip  902 . The openings  904  receive nails or other fasteners that secure the clamping strip  902  to the roadway  114 , thereby clamping the tile segment  202  between the clamping strip  902  and the roadway  114 . In various embodiments, the clamping strip  902  is secured to the roadway  114  and/or the tile segment  202  with nails or other fasteners and/or an adhesive.  
         [0054]     The tactile surface  100  includes various functions. The function of indicating the direction of the tactile surface  100  is implemented, in one embodiment, by the pair of spaced apart parallel raised ribs  204  oriented parallel to the direction  218  of travel along the surface  100 . The area  209  between the raised ribs  204  receives a cane tip  220 , thereby providing tactile feedback of the location of the surface  100 .  
         [0055]     The function of providing tactile feedback to a pedestrian  212  without creating a tripping hazard is implemented, in one embodiment, by the raised ribs  204  protruding from the surface of the base  304  and by the raised ribs  204  having a rounded profile along the sides and exposed ends  302 -A, thereby not presenting a surface or edge susceptible to catching an object, such as a shoe or other footwear.  
         [0056]     The function of avoiding a tripping hazard is implemented, in one embodiment, by the raised ribs  204 -A having a rounded profile along the sides and ends  302 , thereby not presenting a surface or edge susceptible to catching an object, such as a shoe or other footwear.  
         [0057]     The function of guiding a person  212  is implemented, in one embodiment, by the pair of spaced apart parallel raised ribs  204  aligned parallel to the direction  218  of travel along the surface  100 . Such alignment allows the person  212  to detect the presence of the tactile surface  100  and to detect the direction  218  in which the surface  100  leads.  
         [0058]     The function of indicating a location on the surface  100  is implemented, in one embodiment, by the gap  210  in the raised ribs  204 -A. The gap  210  is dimensioned and configured to be detected by a cane tip  220  as the tip  220  passes along the area  206  between the raised ribs  204 .  
         [0059]     The function of joining the raised ribs  204  for the surface  100  without creating a hazard is implemented, in one embodiment, by the square-cut ends  302 -B of the raised ribs  204 -E butted together to form a joint  208 . In another embodiment, the function is implemented by the angle-cut ends  302 -C of the raised ribs  204 -E butted together to form a joint  208 .  
         [0060]     From the foregoing description, it will be recognized by those skilled in the art that a tactile surface  100  disposed on a pedestrian surface has been provided. In one embodiment, the tactile surface  100  includes a pair of raised ribs  204  that are evenly spaced, parallel, and have a longitudinal axis parallel to, or aligned with, the direction  218  of travel of the tactile surface  100  and the walkway. In one embodiment of the surface  100 , the raised ribs  204  protrude from a base  304  of a tile segment  202 . In one such embodiment, the tile segments  202  are secured to the roadway  114  or other surface by an adhesive. In another embodiment of the surface  100 , the raised ribs  204  protrude from the substrate forming the surface of the walkway. That is, the raised ribs  204  are integral with the roadway  114  or other surface.  
         [0061]     While the present invention has been illustrated by description of several embodiments and while the illustrative embodiments have been described in considerable detail, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of applicant&#39;s general inventive concept.