Patent Publication Number: US-7591606-B2

Title: Method and system for vehicular traffic management

Description:
FIELD OF THE INVENTION 
   The invention relates to vehicular traffic management, and more particularly to managing such traffic using speed bumps. 
   BACKGROUND OF THE INVENTION 
   Speed bumps are a widespread means for controlling traffic. They are often used in locations where the potential for collisions is greater than normal, such as in construction zones, toll ways, entrance and exit ramps, school zones and residential areas. 
   A typical speed bump is a permanent structure integrated with a road surface, such as an asphalt, concrete, or steel structure whose shape resembles that of a cylinder sliced longitudinally. The speed bump is placed across a road to encourage drivers of vehicles to slow down when passing thereon lest they suffer a large jolt. 
   Despite their effectiveness, there is at least one drawback associated with conventional speed bumps. Emergency vehicles, such as ambulances, police cars and fire trucks, are forced to slow down when traversing a speed bump in a roadway, resulting in greater emergency response times. 
   Thus, there is a need for a method and system that has the benefit of conventional speed bumps for curtailing the speed of vehicles, while at the same time not hampering the motion of emergency vehicles. 
   SUMMARY OF THE INVENTION 
   An improved traffic management method and system are described herein. In accordance with one aspect of the present invention, a speed bump system and method are described that provide for gaps to allow an emergency vehicle to pass therethrough. In one embodiment that can be implemented when the tire configuration (e.g., width of tires, number of tires, distance between front tires, distance between rear tires) of the emergency vehicle is substantially different from that of a regular passenger vehicle, the speed bump system is designed to allow an emergency vehicle to pass through the gaps, but to not allow the regular passenger vehicle to pass through the gaps. In another embodiment, both an emergency vehicle and a regular passenger vehicle are physically capable of passing through the gaps of the speed bump system. Effectiveness of the speed bump system could, in part, then stem from prohibiting by law a regular passenger vehicle to pass through the gaps. 
   The speed bump system can be pre-fabricated or constructed on site. Reflectors can be disposed between the gaps to increase visibility for emergency vehicles at night. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1A  shows a cross-sectional view of a speed bump system, according to the principles of the present invention. 
       FIG. 1B  shows a tire configuration of an emergency vehicle. 
       FIG. 1C  shows exemplary dimensions of a fire truck. 
       FIG. 1D  shows exemplary dimensions of an ambulance. 
       FIG. 1E  shows exemplary dimensions of a speed bump system, according to the principles of the present invention. 
       FIG. 1F  is a schematic of a tire configuration of an emergency and regular passenger vehicle. 
       FIG. 2A  shows a plan view of another embodiment of a speed bump system, according to the principles of the present invention. 
       FIG. 2B  shows an exploded view of the speed bump system of  FIG. 2B . 
       FIG. 3A  shows a plan view of a speed bump system having an “SOS lane,” according to the principles of the present invention. 
       FIG. 3B  shows a perspective view of the speed bump system of  FIG. 3A . 
       FIG. 4  shows another embodiment of a speed bump system, according to the principles of the present invention. 
       FIG. 5  shows another embodiment of a speed bump system, according to the principles of the present invention. 
       FIG. 6  shows a flow chart of a method for encouraging a driver of a passenger vehicle traveling on a roadway to slow down, while allowing an emergency vehicle to pass therethrough unimpeded, according to the principles of the present invention. 
       FIG. 7  shows another embodiment of a speed bump system, according to the principles of the present invention. 
       FIG. 8  shows a flow chart of another method for encouraging a driver of a passenger vehicle traveling on a roadway to slow down, while allowing an emergency vehicle to pass therethrough unimpeded, according to the principles of the present invention. 
       FIG. 9  shows yet another embodiment of a speed bump system, in accordance with the principles of the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   A speed bump system is described below that provides the traditional benefits of speed bumps, viz., reducing speeds of cars, while not impeding the speed of emergency vehicles. 
     FIG. 1A  shows a cross-sectional view of a speed bump system  10  for a roadway that encourages a driver of a vehicle to slow down. The system  10  is designed, however, to not impede an emergency vehicle. An emergency vehicle can include an ambulance, a fire truck and/or a police car, for example. 
   The speed bump system  10  includes an elongate structure  12  having a raised middle portion  14  with two ends  16  and  18 . The elongate structure  12  also has a first raised outer portion  20  that is proximal to the one end  16  of the raised middle portion  14 , and a second raised outer portion  22  that is proximal to the other end  18  of the raised middle portion  14 . The speed bump system  10  also includes affixing means  24  that can include holes  26  and screws  28  threaded therethrough and screwed to the roadway. Any other type of affixing means, such as bolts, nails, spikes, rivets or bonding material can also be used. Tn some instance, as when using concrete, asphalt or tar, the speed bump system may be self-bonding to the roadway when set. Other methods and components for constructing speed bumps, known to those of ordinary skill in the art, may also be used. 
   The speed bump system  10  also includes a first gap  30  and a second gap  32 . The first gap  30  lies between the first raised outer portion  20  and the raised middle portion  14 . The second gap  32  lies between the second raised outer portion  22  and the raised middle portion  14 . 
   In the simplest case, the emergency vehicle has two front tires, and two back tires, and the distance between the two front tires and the distance between the two rear tires is substantially the same. The width  34  of the first gap  30  (the “intragap width”) and the width  36  of the second gap  32  are then each chosen to be wider than the width of the widest tire tread of the emergency vehicle. Moreover, the distance  38  between the first and second gaps  30  and  32  (the “intergap width”) is chosen to be substantially the same as the distance between the two rear tires of the emergency vehicle, which in this example is substantially the same as the distance between the two front tires. The intergap width can be measured from the center of the first gap to the center of the second gap, if the width between front (or rear) tires is also measured from the respective centers of the two front (or rear) tire treads. 
   Some emergency vehicles have two tires at the location of one tire well. For example, certain fire trucks or ambulances have a single front right tire, a single front left tire, but two rear right tires and two rear left tires. In such cases, the width of a left first gap is wider than both left rear tires (i.e., wider than the distance between the outer edge of the tread of the outer left tire, and the inner edge of the tread of the inner left tire), and the width of a right second gap is wider than the two rear right tires. In this last example, it is assumed that the left front tire tread lies between the two left rear front tires if longitudinally projected there. This last assumption ensures that when the emergency vehicle is traveling straight ahead along a roadway, the two front tires can pass the gap if the two rear wheels can. If this assumption is not true, such as when the tire configuration of the emergency vehicle is like that shown in  FIG. 1B , the intragap distance of the second or right gap should be larger than the transverse distance  21  between the edge  23  of the tread of the outermost tire  25  and the inner edge  27  of the inner most tire  29 . Analogous considerations apply for the first or left gap. 
   Generally, where the speed bump is tailored for one or more emergency vehicles, including vehicles where the distance between two front tires and the distance between two rear tires are not equal, and/or where the vehicle has a plurality of wheels at a single wheel well, the width of the individual gaps (the “intragap width or distance”) and the distance between the gaps (the “intergap distance”) should be such as to allow the emergency vehicle to pass the speed bump system through the gaps. 
   In the embodiment shown in  FIG. 1A , the first raised outer portion  20 , the raised middle portion  14  and the second raised outer portion  22  are substantially collinear. 
     FIGS. 1C ,  1 D and  1 E show some exemplary dimensions of a fire truck, an ambulance and the speed bump system on a roadway  39  of the present invention. In one embodiment of the present invention, the speed bump system exploits the fact that the distance between the back (or front) wheels of a fire truck or other emergency vehicle, is larger than the analogous distance in a regular passenger vehicle. If such is the case, the intragap distance and the intergap distance may be able to be chosen so that it is possible for the fire truck or other emergency vehicle to travel between the gaps unimpeded, but it is not possible for a regular passenger vehicle to pass the speed bump system without going over at least one of the raised portions. 
   More generally, provided the wheel geometry of the emergency vehicle and the wheel geometry of the regular passenger vehicle is sufficiently different, then the intragap and intergap distances can be chosen such that a) the emergency vehicle is able to pass the speed bump system through the gaps, avoiding the raised portions, and b) the passenger vehicle is not able to pass the speed bump system through the gaps, but must instead traverse at least one of the raised portions of the system. 
   For example,  FIG. 1F  shows a schematic, in plan view, of a tire configuration  52  of an emergency vehicle and a tire configuration  54  of a regular passenger vehicle that are sufficiently different from each other to allow the emergency vehicle to pass the speed bump system  56  through gaps  58  and  60  unimpeded, but not the regular passenger vehicle. To pass the speed bump system  56 , the regular passenger vehicle must go over at least one raised portion  62 ,  64  or  66 . 
     FIG. 2A  shows, in a plan view, another embodiment of a speed bump system  110  in which several segments comprise an elongate structure. The speed bump system  110  includes an elongate structure  112  having a raised middle portion  114  with two ends  116  and  118 . The elongate structure  112  also has a first raised outer portion  120  that is proximal to the one end  116  of the raised middle portion  114 , and a second raised outer portion  122  that is proximal to the other end  118  of the raised middle portion  114 . The speed bump system  110  also includes affixing means  124  that can include holes  126  and screws  128  threaded therethrough and screwed to the road. Other affixing means can also be used, such as nails, spikes and rivets. 
   The speed bump system  110  also includes a first gap  130  and a second gap  132 . The first gap  130  lies between the first raised outer portion  120  and the raised middle portion  114 . The second gap  132  lies between the second raised outer portion  122  and the raised middle portion  114 . 
   Suppose, for simplicity, that the emergency vehicle has two front tires, and two back tires, and the distance between the two front tires and the distance between the two rear tires is substantially the same. The width  134  of the first gap  130  (the “intragap width”) and the width  136  of the second gap  132  are then each chosen to be wider than the width of the widest tire tread of the emergency vehicle. Moreover, the distance  131  between the first and second gaps  130  and  132  (the “intergap width”) is chosen to be substantially the same as the distance between the two rear tires of the emergency vehicle, which in this example is substantially the same as the distance between the two front tires. These dimensions allow the emergency vehicle to pass through the first and second gaps  130  and  132 . 
   The elongate structure  112  includes a plurality of segments  140 ,  142 ,  144  and  146  that are connected together.  FIG. 2B  shows these segments  140 ,  142 ,  144  and  146  separated from each other. The shape of one end  150  of segment  140  is complimentary to the shape of one end  151  of segment  142  to allow segments  140  and  142  to mate with each other. Likewise, other adjoining segments mate in similar fashion. Conveniently, the segments  140 ,  142 ,  144  and  146  can be transported to the installation site where they can be snapped together on site to build the speed bump system  110 . Instead of snapping together, in a different embodiment, the segments can simply be abutted or placed next to each other without snapping or locking together. Affixing means  124  affix the segments to the roadway. 
     FIGS. 3A and 3B  show a plan view and a perspective view of a speed bump system  198  having an “SOS lane”  200  that allows the wheels of an emergency vehicle traveling thereon to pass through a first gap  230 , between a middle raised portion  213  and a first raised outer portion  220 , and a second gap  232 , between the middle raised portion  213  and a second raised outer portion  222 , according to the principles of the present invention. Optionally, the SOS lane  200  can have markings  250 . The markings  250  can spell out “SOS” in Morse code. Some or all of these markings can include reflective material for ease of visibility at night. Other reflectors  251  can be disposed in or proximal to the gaps  230  and  232 , again for ease of visibility. 
   The SOS lane  200  is reserved for emergency vehicles, for example an ambulance  202  or fire truck  204 . A non-emergency vehicle, such as a regular passenger vehicle  206 , would not be permitted to travel in the SOS lane. Instead, the passenger vehicle  206  is permitted to pass the speed bump system by going over the raised portions  220  or  222 , thus encouraging the driver to slow down. In contrast, an emergency vehicle  202  or  204  can travel in the SOS lane and pass through the gaps  230  and  232 , thus traveling unimpeded. In some embodiments, depending on the intragap and intergap distances chosen, and on the geometries of the wheels of a typical emergency vehicle and a typical passenger vehicle, the typical passenger vehicle cannot pass the speed bump system without going over at least one of the three raised portions  213 ,  220 ,  222 , as described above. 
     FIG. 4  shows another embodiment of a speed bump system  360 . The speed bump system  360  includes an elongate structure  362  having a raised middle portion  364  with two ends  366  and  368 . The elongate structure  362  also has a first raised outer portion  370  that is proximal to the one end  366  of the raised middle portion  364 , and a second raised outer portion  372  that is proximal to the other end  368  of the raised middle portion  364 . 
   The speed bump system  360  also includes a first gap  380  and a second gap  382 . The first gap  380  lies between the first raised outer portion  370  and the raised middle portion  364 . The second gap  382  lies between the second raised outer portion  372  and the raised middle portion  364 . 
   Suppose, for simplicity, that the emergency vehicle has two front tires, and two back tires, and the distance between the two front tires and the distance between the two rear tires is substantially the same. The width  384  of the first gap  380  (the “intragap width”) and the width  386  of the second gap  382  are then each chosen to be wider than the width of the widest tire tread of the emergency vehicle. Moreover, the distance  387  between the first and second gaps  380  and  382  (the “intergap width”) is chosen to be substantially the same as the distance between the two rear tires of the emergency vehicle, which in this example is substantially the same as the distance between the two front tires. These dimensions allow the emergency vehicle to pass through the first and second gaps  380  and  382 . 
   In the embodiment shown in  FIG. 4 , the raised middle portion  364 , the first raised outer portion  370  and the second raised outer portion  372  are distinct portions, which would be unconnected absent the roadway on which the three portions are disposed. The three portions  364 ,  370  and  372  can be formed using substances such as tar or asphalt, tamped into shape, for example. These substances, when set, adhere to the roadway, and thus the speed bump system  360  does not require further fastening means. 
     FIG. 5  shows another embodiment of a speed bump system  410 . The speed bump system  410  includes a structure  412  having a raised middle portion  414  with two ends  416  and  418 . The structure  412  also has a first raised outer portion  420  that is proximal to the one end  416  of the raised middle portion  414 , and a second raised outer portion  422  that is proximal to the other end  418  of the raised middle portion  414 . 
   The speed bump system  410  also includes a first gap  430  and a second gap  432 . The first gap  430  lies between the first raised outer portion  420  and the raised middle portion  414 . The second gap  432  lies between the second raised outer portion  422  and the raised middle portion  414 . 
   Suppose, for simplicity, the emergency vehicle has two front tires, and two back tires, and the distance between the two front tires and the distance between the two rear tires is substantially the same. The transverse width  434  (i.e., the distance along an imaginary axis perpendicular to the roadway) of the first gap  430  and the transverse width  436  of the second gap  432  are then each chosen to be wider than the width of the widest tire tread of the emergency vehicle. Moreover, the distance  437  between the first and second gaps  430  and  432  is chosen to be substantially the same as the distance between the two rear tires of the emergency vehicle, which in this example is substantially the same as the distance between the two front tires. These dimensions allow the emergency vehicle to pass through the first and second gaps  430  and  432 . 
   Unlike the embodiments shown in  FIGS. 1A and 4 , the first raised outer portion  420 , the raised middle portion  414  and the second raised outer portion  422  are not substantially collinear. In particular, although the first and second raised outer portions  420  and  422  are substantially collinear, the middle portion  414  is staggered relative to the first and second raised outer portions  420  and  422 . In other embodiments, other staggering permutations are possible, such as permutations in which none of the three raised portions are collinear, or in which the first outer raised portion and the middle raised portion are collinear, but not the second raised outer portion, etc. 
   Referring to  FIG. 6 , a flow chart  500  is shown of a method for encouraging a driver of a passenger vehicle traveling on a roadway to slow down while not substantially impeding an emergency vehicle. In step  502 , a raised middle portion is disposed across the roadway. In step  504 , a first raised outer portion proximal to one end of the raised middle portion is disposed across the roadway. In step  506 , a second raised outer portion proximal to the other end of the raised middle portion is disposed across the roadway. The three raised portions are traversable by the passenger vehicle. In addition, the raised portions are disposed in such a way as to leave a first gap between the first raised outer portion and the raised middle portion, and a second gap between the second raised outer portion and the raised middle portion. The width of the first gap, the width of the second gap and the distance between the first and second gaps allow the emergency vehicle to pass through the first and second gaps. Where the tire configuration of the emergency vehicle and the passenger vehicle is sufficiently different, as shown, for example, in  FIG. 1F , the width of the first gap, the width of the second gap and the distance between the first and second gaps can also be chosen so as to not allow the regular passenger vehicle to pass the speed bump system without going over at least one of the raised portions. 
     FIG. 7  shows another embodiment of a speed bump system  600 , in accordance with the principles of the present invention. The speed bump system  600  includes a first raised portion  602  disposed across a roadway  603 , and a second raised portion  604  disposed across the roadway  603 , such that there is a gap  606  between the first raised portion  602  and the second raised portion  604 . The width  608  of the gap  606  is large enough to allow an emergency vehicle to pass therethrough unimpeded. If the width  608  is larger that that of a regular passenger vehicle, the vehicle can physically also pass through the gap unimpeded. However, to motivate drivers of regular passenger vehicles to not pass through the gap, laws might be enacted to prohibit unauthorized vehicles from passing through the gap in normal circumstances (exceptions could be made in an emergency). 
   Referring to  FIG. 8 , a flow chart  750  is shown of another method for encouraging a driver of a passenger vehicle traveling on a roadway to slow down while not substantially impeding an emergency vehicle. In step  752 , a first raised portion is disposed across the roadway. In step  754 , a second raised portion is disposed across the roadway proximal to the first raised portion. The two raised portions are traversable by the passenger vehicle. In addition, the raised portions are disposed in such a way as to leave a gap between the first raised portion and the second raised portion. The width of the gap allows the emergency vehicle to pass therethrough. 
   With reference to  FIG. 9 , showing another embodiment of a speed bump system  700  of the present invention, raised portions  702  and  704  need not be completely perpendicular to the roadway. Thus, for example, the raised portion  702  has a non-zero component in a direction parallel to the roadway. However, the raised portion  702  also has a component in a direction perpendicular to the roadway that is large enough to impede regular passenger vehicles driving along the roadway. In this last embodiment, for the passenger vehicle to pass the speed bump system  700 , it would have to go through the gap  706  between the raised portions  702  and  704 , as described above. 
   It should also be understood that the raised portion need not be any particular shape, again as long as the shape impeded a regular passenger vehicle from passing the speed bump system in any manner except through the gap or gaps. 
   Also, the height of a raised portion need not be uniform along its longitudinal length. For example, the middle raised portion might be higher near the middle than near the ends thereof. Also, one of the raised portions might have a different height than another one of the raised portions. 
   While embodiments of this invention have been illustrated in the accompanying drawings and described above, it will be evident to those skilled in the art that changes and modifications may be made therein without departing from the essence of this invention. For example, the middle raised portion, and the first and second outer raised portions of the structure of the speed bump system can be connected to each other by material other than the roadway, or they can be unconnected by material other than the roadway. The examples described above are not meant to limit the scope of the invention, which is to be limited by the following claims.