Abstract:
A method is employed for controlling the flow of vehicular traffic in a traffic management zone, as the traffic is routed through a roadway constriction or an area of traffic congestion. Included in the method are steps for establishing a minimum speed, and for identifying a travel lane for each vehicle. The method also includes the requirement that each vehicle not change lanes while it traverses the management zone.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention pertains generally to methods for controlling vehicular traffic on a roadway. More particularly, the present invention pertains to methods for controlling vehicular traffic in a traffic management zone as the traffic is being routed through a constriction in the roadway or through an area of extreme traffic congestion. The present invention is particularly, but not exclusively, useful as a method for controlling vehicular traffic wherein the method includes requirements for a minimum or constant vehicular speed, a minimum spacing between vehicles, and proscriptions against lane changes.  
       BACKGROUND OF THE INVENTION  
       [0002]     It has been documented that delays caused by traffic congestion are increasingly responsible for a significant diminution in workplace productivity. Further, it is well known that traffic congestion contributes to driver-instability (road rage) and other stress-related discomforts. In general, the slower traffic is able to move along a roadway, the more likely it is that stress-related incidents will result.  
         [0003]     While traffic delays that are caused by accidents or acts-of-God may be unavoidable, many other causes of traffic delay are simply the result of poor planning. In particular, traffic delays caused by planned roadway constrictions that are intentionally created to accommodate the reconstruction, repair or alteration of a portion of a roadway, should be managed to insure a minimal disruption in the flow of traffic. Even in situations where traffic delays may be unavoidable, traffic management plans should be implemented to ameliorate the consequences as much as possible.  
         [0004]     To use fluid mechanics principles as an analogy to vehicular traffic flow, it is well known that the speed at which a fluid flows through a conduit is a consequence of whether the fluid flow is laminar or turbulent. On the one hand, laminar flow is characterized by having a relatively steady speed. This is because in laminar flow the fluid generally flows along defined path lines and is relatively smooth and uniform. On the other hand, in contrast with laminar flow, turbulent flow is characterized by fluctuating irregularities that increase friction and drag in the fluid. As a consequence of this, turbulent flow results in overall, measurably slower velocities (speeds) for the fluid. In the context of vehicular traffic, these same general fluid-flow concepts translate to the realization that vehicle lane changes on a roadway can significantly contribute to reductions in the overall speed of traffic flow.  
         [0005]     In light of the above, it is an object of the present invention to provide a method for vectoring vehicular traffic in defined traffic management zones to control traffic speeds along the length of a roadway. More specifically, it is an object of the present invention to provide a method for vectoring vehicular traffic through traffic management zones that combines a prohibition for lane changes in the zone, with specified spacing between vehicles, and a requirement to maintain traffic speeds above a predetermined minimum or constant speed. Another object of the present invention is to provide a method for vectoring vehicular traffic that is relatively easy to implement and comparatively cost effective.  
       SUMMARY OF THE INVENTION  
       [0006]     In accordance with the present invention, methods for vectoring vehicular traffic along a roadway are provided for the purpose of maintaining vehicular speeds above a predetermined minimum. In particular, the methods of the present invention pertain to vehicles that are traveling in the same direction on a roadway, in a plurality of same-way lanes. Essentially, the methods of the present invention require the concerted implementation of three traffic management control conditions. These are: 1) proscribing lane changes by vehicles within a traffic management zone; 2) establishing specified spacings between vehicles; and 3) requiring vehicles to maintain either a minimum speed (e.g. 10 mph) or a constant speed while traversing the zone.  
         [0007]     As a function of the length and width of the defile, and the time that the defile is expected to persist, lane separation may be enhanced by the use of a barrier system. Specifically, such a barrier system for separating the lanes can be implemented by using devices such as vertical wands or concrete dividers.  
         [0008]     For the implementation of the methods of the present invention it is envisioned that the traffic management zone will have a predetermined length that extends between a start point and an end point. The exact length of the zone and the number of same-way lanes in the zone are variable. Specifically, the characteristics of the zone will vary depending on the particular exigencies and requirements of the situation. Once the traffic management zone has been identified, however, it is necessary to provide effective visual notice of the traffic travel requirements in the zone. For the present invention, this notice must at least include the posting of signage that substantially indicates a “minimum or constant speed” requirement, as well as a “no lane change”/“stay in lane” requirement. Preferably, such signage is posted adjacent a flashing light or some other visual attraction, and is positioned on a side of the roadway at a predetermined upstream distance from the zone start point (e.g. greater than approximately five hundred feet). Additional notice can, of course, be provided. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]     The novel features of this invention, as well as the invention itself, both as to its structure and its operation, will be best understood from the accompanying drawings, taken in conjunction with the accompanying description, in which similar reference characters refer to similar parts, and in which:  
         [0010]     The FIGURE is a schematic plan view of a traffic management zone along a portion of a roadway.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0011]     Referring to the FIGURE, a schematic representation of a traffic management zone in accordance with the present invention is shown, and is generally designated  10 . Specifically, the FIGURE provides details for one side of a roadway  12  which has been constructed with a plurality of same-way lanes. The roadway  12 , for the exemplary case shown in the Figure, provides for three lanes of same-way traffic which will travel on the roadway  12  in the direction indicated by the arrow  14 . In accordance with customary usage, these lanes are numerically referred to according to their distance from the median strip  16  of the roadway  12 . Thus, the same-way lanes shown in the FIGURE are referred to hereinafter as lane “ 1 ” (i.e. the fast lane), lane “ 2 ”, and lane “ 3 ”. There could, of course, be more correspondingly higher numbered lanes. In any event, vehicular traffic in these lanes will typically travel in the opposite direction (indicated by the arrow  18 ) to the traffic that is traveling on the other side of the median strip  16 .  
         [0012]     In detail, the traffic management zone  10  is shown to include both a defile zone  20  and a pre-defile zone  22 . As envisioned for the present invention, the defile zone  20  will have a length  24  that varies according to the exigencies and requirements of the particular situation. For example, if the roadway  12  is under construction, or is being repaired, the length  24  of defile zone  20  will extend to include the affected area of roadway  12 . It may also happen that a particular stretch of roadway  12  is particularly susceptible to traffic congestion. In this latter case, the length  24  of defile zone  20  will be established according to a traffic plan. In any case, the defile zone  20  will most likely be more than approximately one hundred feet. The pre-defile zone  22 , on the other hand, will extend through an upstream distance  26  that is dependent on the ability of traffic to enter the defile zone  20  and is, therefore, determined strictly according to a traffic plan.  
         [0013]     As shown in the FIGURE, the traffic management zone  10  begins at a start point  28  on the roadway  12  and ends at an end point  30 . The distance between these points  28  and  30  includes both the length  24  of the defile zone  20  and the upstream distance  26  of the pre-defile zone  22 . Importantly, the start point  28 , which is at the beginning of the pre-defile zone  22 , is identified on the roadway  12  by a sign  32 . Although the sign  32  may be augmented or complemented by other signs (not shown) the import of sign  32  is that near the start point  28  of the traffic management zone  10 , and on through the pre-defile zone  22 , a traffic notice needs to be somehow given to vehicular traffic (e.g. car  34 ). In particular, this notice must include an alert that specified traffic requirements are about to be imposed. Specifically, as envisioned for the present invention, the sign  32  needs to indicate that in the upcoming defile zone  20 : there is a minimum or constant speed that must be maintained; lane changes are not allowed; and, a minimum spacing between in-file vehicles is required. As also shown in the Figure, the visibility of the sign  32  may be enhanced by the use of a flashing yellow light  36 , and the defile zone  20  may be identified by the appropriate placement of traffic cones  38  with additional signage (not shown).  
         [0014]     In the operation of the traffic management zone  10 , and in compliance with the notice of sign  32 , after passing the start point  28  and entering the pre-defile zone  22 , a car  34  traveling in lane “ 3 ” would be required to make a lane change. Specifically, while traveling in the pre-defile zone  22  within the upstream distance  26  from the defile zone  20 , the car  34  would be required to change to lane “ 2 ”, as indicated by the arrows  40   a  and  40   b . Also, as indicated by the arrows  42 , it would be possible for a car  44  in lane “ 2 ”, that is traveling in the predefile zone  22 , to either stay in lane “ 2 ” or change from lane “ 2 ” to lane “ 1 ”. No vehicle, however, would be allowed to enter lane “ 3 ” in the pre-defile zone  22 . Most importantly, once vehicles (e.g. cars  34  and  44 ) are in the defile zone  20 , the arrows  46   a  and  46   b  indicate they must stay in their present lane, with no further lane changes allowed. As indicated above, in addition to staying in their present lane, vehicles would also be required to maintain both a minimum or constant speed and a specified spacing in the defile zone  20 . Upon exiting the defile zone  20 , all vehicles would be allowed to change lanes, as indicated by the arrow  48 , and continue with their normal travel.  
         [0015]     While the above discussion has considered lane “ 3 ” to be the traffic lane that is impacted by a constriction in the defile zone  20 , it is to be appreciated that the present invention is applicable when other lanes of traffic need to be closed. In particular, a similar operation would be implemented if lane “ 1 ” were to be closed and lane “ 3 ” left open. Indeed, the present invention applies to any situation wherein a plurality of side-by-side lanes are to be established in a defile zone  20 . This is so regardless whether there is an actual constriction to the roadway  12  in the defile zone  20 .  
         [0016]     While the particular Method for Managing Vehicular Traffic as herein shown and disclosed in detail is fully capable of obtaining the objects and providing the advantages herein before stated, it is to be understood that it is merely illustrative of the presently preferred embodiments of the invention and that no limitations are intended to the details of construction or design herein shown other than as described in the appended claims.