WO2004007930A2

WO2004007930A2 - Vehicle speed limiting method and apparatus

Info

Publication number: WO2004007930A2
Application number: PCT/US2003/003766
Authority: WO
Inventors: John F. Dorsey
Original assignee: Dorsey Innovations, Inc.
Priority date: 2002-07-16
Filing date: 2003-02-07
Publication date: 2004-01-22
Also published as: WO2004007930A3; AU2003210918A8; AU2003210918A1

Abstract

Disclosed is an apparatus and method for limiting the speed of a vehicle to a consumer changeable and lockable maximum speed, and of flexibly enforcing this speed limit such that the driver has the ability to exceed the maximum speed for brief periods of time as necessary for safe driving. The inventive apparatus also allows for the inclusion of an emergency override button (28), which provides even greater flexibility.

Description

VEHICLE SPEED LIMITING METHOD AND APPARATUS

BACKGROUND OF THE INVENTION

Technical Field

The present invention relates generally to devices for limiting the traveling speed of a motor vehicle, and more particularly to a software-mediated method and apparatus for limiting the speed of a vehicle to a changeable and lockable maximum speed, and of flexibly enforcing this speed limit such that the driver has the ability to exceed the maximum speed for brief periods of time as necessary for safe driving.

Background Art

Studies of highway traffic accidents show that excessive vehicle speed is consistently a leading cause of accidents, injuries, and fatalities. In the year 2000 alone, 12,350 people were killed, and another 700,000 were injured in speed-related accidents in the United States. Speed was a contributing factor in almost 30% of all fatal accidents in that year, and the percentage among younger drivers is even higher. Clearly, there is a need for technology that can help limit the speed of vehicles for drivers who are at the highest risk without compromising the driver's ability to avoid dangerous situations.

Various kinds of absolute speed governors are well known and their use on large commercial trucks is common. In fact, most consumer vehicles have absolute governors installed; however, they are set to extremely high speeds, such as 140 mph (225 kph), designed primarily to prevent the vehicle from structural failure. However, the safety needs of the typical non-commercial driver are not fully met by these systems, because they either do not provide adequate flexibility or they are not designed to lock. For example, U.S. Pat. No. 5,389,051 to Hirate et al, discloses a device that reduces engine speed to idle on small industrial vehicles if an "overspeed" condition is detected. This device is characteristic of locking speed governors in that it does not contemplate and address the myriad urgent situations a vehicle driver may face on public roads.

Another approach to preventing excessive speed is disclosed in U.S. Pat. No. 3,878,915 to Purland et al, which describes a speed control apparatus designed to employ a code entry system that recognizes a "plurality of drivers," rather than to identify whether or not a person is authorized to set and lock the system. Further, Purland et al call for the "hardwiring" of the various speed settings for each driver, rather than allowing for user-controlled speed settings. While this system has merit, it is a fundamentally different approach than that of the present invention.

The prior art also contains many variations of cruise control systems, which may or may not have locking mechanisms. One such device is disclosed in U.S. Pat. No. 4,858,135 to Clish et al, wherein a maximum speed may be set by a driver and then reset at will without a locking mechanism. The present invention improves upon the prior art in that it allows a mechanically unskilled owner to change and lock a maximum speed setting. At the same time it provides for temporary departure from limiting control so that a driver can avoid a dangerous situation that calls for speed above the set maximum, e.g., passing at highway speeds. Further, it provides the necessary flexibility to implement the system in original mass production vehicles so that a viable speed control system can be made available to the typical consumer.

Disclosure of Invention

The present invention addresses the problem of excessive speed by providing a flexible speed control device that can be locked and changed by the vehicle owner. A preferred embodiment of this device includes a user interface, a software control module that operates within the vehicle's on-board computer, a speed sensor that senses and sends a vehicle speed signal to the on-board computer, and the actuating mechanisms capable of physically accomplishing the software module's commands. These elements collectively operate to create the characteristics and features of the system, as described more fully below. Of course, every modern vehicle in mass production has a specific and unique process for implementing the commands of its computerized engine management system, so the exact implementation of the inventive system and the means of control between the computer and vehicle systems will vary by vehicle model. The complexity of the implementation also depends upon how the manufacturer chooses to allow the system to reduce speed, as discussed further below.

The inventive speed control system includes standard and optional features, including the following: Basic Features: These features include, (1) a user interface that allows a consumer to set, change, and lock a maximum speed setting; (2) a software module that operates the speed control system; (3) speed sensor which generates and sends a signal indicating vehicle speed to the software module; and (4) actuating mechanisms operationally connected to the software module capable of physically slowing a vehicle. Together these features prevent a driver from exceeding a set maximum speed.

Optional Features: These features include, (1) flexibility allowance to permit a driver to exceed the predetermined set maximum speed for a specified period of time; (2) an abuse control function that prohibits the driver from exceeding the set speed before driving below the set speed for a specified period; (3) an abuse control function that prohibits the driver from exceeding the set speed more than a specified number of times in a specified period of time; (4) an emergency override feature that disables speed control for a specified period of time; (5) an emergency alert feature that produces audible sounds or illuminates lights or LEDs after an emergency override is used until the correct pass code is entered or a key is toggled; (6) an emergency alert feature that sends a distress signal via satellite communications when an emergency override is used; and (7) a status display feature that informs the driver of the current state of the speed control device.

Brief Description of the Drawings FIG. 1 A is an illustrative view of a user interface for the present invention;

FIG. IB is an illustrative view of a two panel side-by-side display providing information to a driver of the state of an operating speed control system;

FIG. 2A is a block diagram showing possible software architecture to implement the speed control function of the present invention; FIG. 2B is a block diagram showing possible software architecture to implement the emergency function of the present invention; and

FIG. 3 is graph showing time indicated on the x-axis and speed indicated on the y- axis, said graph illustrating one way in which a vehicle may be governed by the present invention. Best Mode for Carrying Out the Invention

Conventional nomenclature is used in connection with the figures to indicate well- known variables. For easy reference, however, nomenclature for all variables is set forth as follows:

V MAX Maximum speed setting - set by vehicle owner/authorized person;

Period of time that the speed control device waits before acting to correct an overspeed condition - set by manufacturer or owner and may be equal to zero; Rt Period of time after correcting an overspeed condition that the speed control device acts as an absolute speed governor - used in Abuse Control Function A;

R MAX Number of resets allowed in T_j^ period of time - used in Abuse Control

Function B; ^lR2 Period of time during which no more than R_MA number of resets may occur - used in Abuse Control Function B;

"R2 Counter variable that equals the number of resets in the past T_j^ period of time

- used in Abuse Control Function B;

Timer that begins counting when an overspeed condition first occurs and stops counting when T_f is reached - may not appear in software if T_f is equal to zero or is not present; Rlc Timer that begins counting when t_fo is greater than or equal to T_f AND the overspeed condition has been fully corrected - stops counting when T_R1 has been reached - used in Abuse Control Function A; and T_E Period of time that speed control is disabled if the Emergency Override Button is pressed. Referring now to FIGS. 1 A-3, wherein like reference numerals indicate like elements in the various views, FIG. 1 is an illustrative view of the first component of the present invention, namely a user interface 10. The interface comprises a console 12 which preferably includes a standard numeric (twelve-key) pad 14, "On", "Off, and "Set" control buttons, 16, 18, 20, an "Active" LED indicator 22 (optional), a numerical display 24, "Up" and "Down" speed selection buttons 26, an "emergency override" button 28, and an "emergency override" indicator LED 30.

The functions of the various elements of FIG. 1 are straightforward. The twelve-key pad is used to enter a pass code that enables control of all the device settings controllable by the vehicle owner or user. By entering the correct pass code, the owner can set the speed control device to "On" or "Off," set the desired maximum speed, and change the pass code (optional).

The "Up" and "Down" buttons are used when the speed control device is in "Set" mode to select the maximum speed setting, which is then illuminated in the numerical display. The "Active" LED is an optional feature, which may be illuminated whenever the device is in the "On" mode, or when it is actively controlling speed, at the option of the manufacturer. The "emergency override" LED is illuminated when the emergency override button is pushed. This LED is part of the system to alert the vehicle owner that the emergency button has been used. Therefore, it is intended to either remain illuminated or blink until someone enters the correct pass code.

The emergency override button disables speed control for a specified period of time. During this time, the vehicle will respond to all driver inputs as if the speed control device were turned off. After the specified period of time has elapsed, the emergency override function re-enables full operation of the speed control device. Of course, if the device is set to "Off or "Set" mode during the emergency override time period, thereby disabling the speed control device, then the emergency override will itself be overridden and canceled at the time the speed control device is so disabled.

As illustrated in FIG. 1, the user interface may be a simple console having control buttons and visual displays. Numerous variations are possible, however, and it will be readily apparent to those having skill in the art to modify the interface to facilitate ease of use or simply to incorporate aesthetically pleasing elements. For instance, the functions of the "On", "Off, and "Set" buttons may be incorporated into the twelve-key pad, and further, that the entire twelve-key pad and/or three control buttons may be replaced with a two- or three- position key switch or a dial with a corresponding visual indicator to signify numeric entries. If a twelve-key pad is used, it may be designed so that the vehicle owner may change the pass code from time to time. The numeric (visual) display may be supplemented or replaced by an audio output device which audibly recites a setting when selected. Also, the emergency override button (if included) must be easily and readily accessible to the driver, but the remainder of the interface may be located remotely in the vehicle and generally out of easy reach of the driver. The preferred interface is simple in form, and does not require that the end user have any particular electronic or mechanical skill to simply set and lock the maximum speed setting after entering an appropriate pass code (or using the speed control key, if a key switch is installed).

The user interface also preferably includes a visual display or audible output that informs the driver of the current state of the speed control device. The display can be as simple as an "Active" LED 22 that illuminates when the device is actively reducing or limiting speed, or an audible output which informs the driver that the device is active. Alternatively, it may be as complex as a set of numerical displays that "count down" important individual periods of time so that the driver knows when to anticipate the actions of the speed control device. For example, as shown in FIG. IB, a console 32 having two side- by-side timer displays 34, 36, may be provided on a panel in the driver's field of vision. One timer holds steady at the number of seconds equal to T_f, while the other holds steady at T_R1. When an overspeed condition is detected, the first display 34 begins counting down so that the driver knows exactly when the speed control device will begin reducing speed. Once a period of time equal to T_f has elapsed and the vehicle has slowed below the maximum speed setting, then the second timer display 36 begins counting down to let the driver know when he or she will have speed flexibility again. A similar approach may be used to incorporate a third countdown display based on T^. There are many other ways to display this type of information, but the key point is that the driver is given some indication, however detailed, and whether real-time or in advance, of the status of the speed control device. The second component of the speed control system is software that operates and controls the inventive apparatus. FIGS. 2A and 2B represent possible software architectures to implement the speed control and emergency functions of present invention. The overall system architecture preferably comprises two primary functions: (1) speed control; and (2) emergency override. However, a system need not be equipped with either an abuse control feature or an emergency override feature. The software may be simplified if one or both features are not implemented.

Referring now to FIG. 2A, the speed control function 40 activates when the speed control device is itself active. The function begins in a normal driving state 42, in which no action is taken by the speed control device. The function remains in this state until an overspeed condition 42 is detected by vehicle speed sensing means (not shown). At that point, the t_fc clock or timer 44 begins counting. No other change occurs until that timer becomes greater or equal to T_f, at which point the function will determine 46 if the vehicle is still traveling in excess of Y_MJ^. If SO 48, the function will begin reducing speed 50 until the vehicle is slowed to V_M^. If not 52, the function will proceed immediately to the next step 54, in which t_fc is stopped and t_Rlc is started.

At this point in the program 56, the speed control device will not permit acceleration to a speed beyond V_M^. The device will remain in an absolute governor mode until t_Rlc equals or is greater than T^ and c^ is less than R_MA - Once this condition occurs 58, t_fc is reset, t_Rlc is stopped and reset, and c^ is incremented 60. Finally, the function returns to the original normal driving state while retaining the value of c^ until enough time has passed for c^ to be decremented. Referring now to FIG. 2B, the emergency override function 70 begins in a state that specifies no action 72, and it remains there until the driver presses 74 the emergency override button. Once the button is pressed, the emergency override function disables the speed control function 76, and activates all alerting features available 78. The alerting features may include LEDs, sounds, and distress signals sent 80 via an installed satellite communications device. The function will then remain in a waiting condition 82 where speed control is disabled until a specified period of time, T_E 84, has elapsed. At that point, the emergency override function will reactivate speed control 86 if the device is still enabled. However, all emergency alert features will remain on, though they may be less prominent than when speed control is actively being disabled. FIGS. 2 A and 2B are diagrams showing possible software architecture for organizing appropriate system code, but they represent just one possibility. There are multitudes of complex and sophisticated approaches that a skilled programmer could take to accomplish the same task as laid out in FIGS. 2A and 2B. In fact, the actual software code in the speed control system will necessarily vary to adapt it to the particular model of vehicle and engine management system for which it is devised. It will also vary based upon the number of optional features that a manufacturer chooses to include in the speed control system. The description of the software given here assumes that all optional features of the speed control device are installed. The diagrams also do not show the state diagram for the setting of the maximum speed, which is simply a matter of entering the correct pass code (or tuning the key), selecting the desired speed, and then pressing "Set" or tuning the key to "On". It is notable, however, that a manufacturer may limit the range in which the maximum speed can be set. A range of 45 mph to 75 mph (approximately 70 to 120 kph) may be a reasonable limitation.

To summarize, the software begins in a state of inaction once the vehicle is on and the speed control device is activated. It remains in that state until an overspeed condition is sensed by vehicle speed sensing means (not shown) and a vehicle speed indicator signal sent to the software control module. The overspeed condition may be addressed immediately, or the software may allow some leniency in terms of the magnitude or amount of time the overspeed exists before it changes state and commences counting or undertakes corrective speed reduction.

Once the software changes state, preferably it will begin counting time until it reaches the period specified as the period of flexibility (T_f in FIGS. 2A and 3). Once the software determines that the period of flexibility has ended, it will reduce the speed of the vehicle if the speed is still in excess of the set maximum. The precise formula for the rapidity of the speed reduction (linear or exponential; slow or rapid), as well as the number of vehicle systems involved (fuel flow, engine braking, and wheel braking) are choices for each manufacturer.

When the vehicle stabilizes at or below the set maximum speed, the software then enters a temporary absolute governor mode, during which time the vehicle may not exceed the maximum set limit at all. The vehicle remains in this mode until a specified amount of time, T_R1, has passed. At that point, the driver is free to exceed the maximum speed if necessary, and if he or she does so, then the above-described process will repeat.

The flexibility to speed is not unrestricted, however, as the manufacturer may limit the number of times that speed control system will reset itself, R_MAX, in a given period of time, T_RJ. If this number of resets has been exceeded, the speed control system will remain in absolute governor mode until enough time has elapsed for the oldest reset to expire from the counter, c^,. It may be noted that the c^ counter may be decremented by a separate function that records time values and decrements c^ at the appropriate time; or c^ itself may be implemented as a custom object type consisting of a counter and an appropriate number of time variables for the specified R _A -

The emergency override function has the capability to interrupt and reset the speed control function. Therefore, if a driver presses the emergency button, the speed control device follows the emergency algorithm and not the speed control algorithm. Entry of the correct pass code will instantly disable and reset both the speed control function and the emergency override function, as well as deactivate any emergency alert features that may be active. The emergency override function works as outlined in the description of FIG. 2B. Its primary purpose is, of course, to disable speed control for a specified period of time, T_E, in the event of an emergency, and to activate alerting systems that will indicate to the vehicle owner that the button has been used. Such alerting functions may remain on until the correct pass code is entered, or they may expire after a given period, such as 24 hours. A short time limit my be advisable, since a primary intended use of this technology is by college students whose vehicle is owned by parents or guardians. In such cases, the owner of the vehicle may be located far away from the vehicle, and it would be distracting for the alerting features to remain active constantly after a single use of the emergency override.

The third and final element of the speed control system is the mechanical actuation of the software commands. The necessary mechanical and signal transmission systems are well known and already installed in virtually all currently manufactured vehicles. That is, vehicles that are equipped with a computer control system already have means of controlling fuel flow to the engine. Furthermore, some portion of the speed control software can be borrowed from existing cruise control systems. Therefore, implementation of the present invention in most vehicles would require only modifications to the existing engine management software code and the installation of the user interface. Additional speed reduction means that may be desirable to include, such as computer-controlled brakes, are also known. Means for sensing vehicle speed and for generating a signal indicative of the speed are also well known, as reflected in the prior art identified in the Background discussion set forth above. The vehicle speed signal is input into the speed control software where it is compared to the settings input by the user or owner.

One difficulty that arises in the process of reducing the vehicle speed by engine fuel flow is how an automatic system can account for the driver shifting into neutral. (The process of accounting for a shift into different gears is a simple matter of the speed control device waiting for the vehicle's default gear shifting process to complete before resuming speed control action via engine control.) Fuel flow reduction obviously has no effect when a vehicle is in neutral, and the vehicle may actually required increased fuel flow during the shifting process for smooth and safe operation, even if the car is exceeding the maximum set speed. Thus, when a driver shifts gears or shifts into neutral, the fuel flow component of the speed control system must defer to the default system installed on the vehicle until the shifting process is complete and a new gear has been set. Therefore, if fuel flow and engine braking are the exclusive means that a manufacturer has chosen to use when implementing the inventive speed control system, then the system may be defeated on downhill driving surfaces by the driver shifting into neutral. If, however, the manufacturer chooses to incorporate computer-controlled braking as part of the speed control system, then the system can simply continue slowing the vehicle with brakes.

FIG. 3 is a representative graph 100 of speed vs. time illustrating how a vehicle's speed would be affected by the operation of the present invention. Several simplifying assumptions were made when constructing this graph, including: (1) that the vehicle is on a level, frictionless, ideal surface and in perfect running order; (2) that the driver of the vehicle attempts to maximize speed at all times; (3) that the speed control device is "On," set to V_MAX, and is equipped with both optional abuse prevention features; (4) that the emergency override feature is either not installed or not used during the period of the graph; and (5) that the manufacturer has set the maximum number of resets (R_MA ) allowed in time period

to two (2).

At t = 0 102 in the graph of FIG. 3, the vehicle is either at rest or at some arbitrary speed less than V_M^. The vehicle then accelerates through V_MAX, and continues to increase speed 104. At the instant the vehicle exceeds V_MAX 106, the t_fc timer begins counting time until it reaches T_f 108. Once t_fc equals or exceeds T_f 110, the speed control device begins slowing the vehicle 112. As previously noted, the speed control device may be operatively connected to any of a number of suitable vehicle speed control means, including fuel flow reduction, engine braking, wheel braking, and/or any combination of these, depending on how the inventive system is implemented in a particular vehicle.

Once the speed control device acts to slow the vehicle, the vehicle continues to slow until V_UAX is reached 114, regardless of any attempt by the driver to increase speed. (Of course, the driver has the ability to slow the vehicle at a faster rate than the speed control system by simply applying the vehicle brakes.) Once the vehicle slows to V_MAX, the speed control device enters an absolute governor mode of operation and the t_Rlc timer begins to count. Once t_Rlc count is equal to or greater than T_R1 116, then t_fC and t_Rlc are reset to zero, and c^ is incremented 118. At this point, the driver again has the ability to accelerate the vehicle, which he does according to the assumptions on which the graph is based. As soon as the vehicle exceeds

the above-described process is repeated. However, after a third round of speeding 120, when c^ is equal to two (2) 122, the timers do not immediately reset. Rather, the device remains in absolute governor mode until C_RJ automatically decrements after the oldest reset has aged at least a period of time equal to T_J 124. In other words, the device does not allow any more than R _AX resets (two in this instance) in any T^ period of time. The speed control system can accomplish this task by keeping track of the number of resets that have occurred, as well as the times at which those resets occurred. The system program can then simply decrement the

counter when a particular reset ages more than a T_j^ period of time.

Once C_R2 is decremented, t_fc and t_R]C can be reset, and the driver has the flexibility to speed once more. Of course, C_R, only remains set to one (1) for enough time for the other counters to be reset, since it must be incremented again because of that reset.

In another aspect, the inventive system may be characterized as a vehicle speed limiting apparatus, comprising a user interface having input means for entering an authorized pass code and at least one maximum speed setting (V_MAX) for limiting excessive vehicle speed; vehicle speed sensing means capable of sensing vehicle speed and generating a vehicle speed signal; a software control module in electronic communication with the user interface and the vehicle speed sensing means, the software control module having a memory for storing the input of V_MA and a speed control function comprising an executable program responsive to said vehicle speed signal and the maximum speed setting; and vehicle speed reduction means in operative connection with the software control module. The above- described optional features may be included as desired.

Also provided by the present invention is a method of limiting the speed of a vehicle, comprising the steps of providing the above-described apparatus and entering a maximum speed setting, preferably only after having to enter an authorized pass code. The present invention is envisioned primarily for application as a factory-installed or dealer-installed option on new consumer vehicles, trucks, and motorcycles, although it may also be manufactured and installed on used cars or as an after-market kit. It is also envisioned that this system could be implemented on older used vehicles without computer control, using known methods of carburetor control and other appropriate mechanical means. Any such implementation that follows the basic form and spirit of the present invention is incorporated in this application.

The foregoing disclosure is sufficient to enable one having skill in the art to practice the invention without undue experimentation, and provides the best mode of practicing the invention presently contemplated by the inventor. While there is provided herein a full and complete disclosure of the preferred embodiments of this invention, it is not intended to limit the invention to the exact construction, dimensional relationships, and operation shown and described. Various modifications, alternative constructions, changes and equivalents will readily occur to those skilled in the art and may be employed, as suitable, without departing from the true spirit and scope of the invention. Such changes might involve alternative materials, components, structural arrangements, sizes, shapes, forms, functions, operational features, or the like. Accordingly, the proper scope of the present invention should be determined only by the broadest interpretation of the appended claims so as to encompass all such modifications as well as all relationships equivalent to those illustrated in the drawings and described in the specification.

Claims

CLAIMS What is claimed as invention is:

1. A vehicle speed limiting apparatus, comprising: a user interface, said user interface including input means for entering a pass code and at least one maximum speed setting (V_MAX) f°^r limiting excessive vehicle speed; vehicle speed sensing means capable of sensing vehicle speed and generating a vehicle speed signal; a software control module in electronic communication with said user interface and said vehicle speed sensing means, said software control module having a memory for storing the input of said maximum speed setting and a speed control function comprising an executable program responsive to said vehicle speed signal and said maximum speed setting; and vehicle speed reduction means in operative connection with said software control module.

2. The vehicle speed limiting apparatus of claim 1, wherein said input means and said software module allow a user to set, change, and lock said maximum speed setting.

3. The vehicle speed limiting apparatus of claim 2, wherein said pass code comprises an electrical signal from a key switch.

4. The vehicle speed limiting apparatus of claim 2, wherein said input means comprises a three position key switch and speed selection buttons.

5. The vehicle speed limiting apparatus of claim 2, wherein said input means comprises on, off, and set buttons.

6. The vehicle speed limiting apparatus of claim 1, wherein said input means comprises a twelve-key pad.

7. The vehicle speed limiting apparatus of claim 6, further including speed selection buttons.

8. The vehicle speed limiting apparatus of claim 6, further including a visual display indicating the V_MAX input by the user.

9. The vehicle speed limiting apparatus of claim 6, further including active indicator output means which provides a user with an indication of the status of the apparatus.

10. The vehicle speed limiting apparatus of claim 9, wherein said active indicator output means comprises an LED.

11. The vehicle speed limiting apparatus of claim 9, wherein said active indicator output means is an audible output device.

12. The vehicle speed limiting apparatus of claim 1, wherein said user interface further includes an emergency override button and said software control module includes an emergency override function, whereby a user may selectively override said speed control function by pressing said emergency override button.

13. The vehicle speed limiting apparatus of claim 12, wherein said emergency override function disables said speed control function for a specified period of time (T_E), wherein during said specified period of time the vehicle will respond to all driver vehicle speed inputs, and wherein after said specified period of time has elapsed, said emergency override function re-enables full operation of said speed control function.

14. The vehicle speed limiting apparatus of claim 1, wherein said speed control function includes a first preset instruction which specifies a flexibility length of time, T_f, equal to or greater than zero seconds, that the apparatus delays before talcing action to correct an overspeed condition.

15. The vehicle speed limiting apparatus of claim 14, wherein T_f instruction specifies a length of time greater than zero seconds and wherein said speed control function includes a first timer (t_fc) that begins counting when an overspeed condition is detected and stops counting when said T_f length of time is reached.

16. The vehicle speed limiting apparatus of claim 15, wherein said speed control function includes a second preset instruction which specifies the length of time, T_Rl, after correcting an overspeed condition that said speed limiting apparatus acts as an absolute governor.

17. The vehicle speed limiting apparatus of claim 16, wherein said speed control function includes a second timer (t_Rlc) that commences counting when said first timer has reached a time greater than or equal to T_f and the overspeed condition has been fully corrected by reducing vehicle speed to or below V_MAX, and wherein said second timer stops ^" counting when said T_R1 period of time has been reached.

18. The vehicle speed limiting apparatus of claim 16, further including a visual display for providing the vehicle driver with an indication of T_fc status and T_R1 status.

19. The vehicle speed limiting apparatus of claim 16, wherein said speed control function further includes a third preset instruction, said third preset instruction specifying the maximum number of times (R_MAX) that the speed control function can be reset after correction of an overspeed condition to enable the user to exceed V_MA -

20. The vehicle speed limiting apparatus of claim 19, wherein said speed control function further includes a fourth preset instruction which specifies the period of time (T^,) during which no more than R_MAX number of resets may occur.

21. The vehicle speed limiting apparatus of claim 20, further including a counter variable, c^, that equals the number of resets that occur in said previous T^ period of time.

22. The vehicle speed limiting apparatus of claim 1, wherein said vehicle speed reduction means is selected from the group consisting of engine brakes, wheel brakes, fuel flow control, and any combination thereof.

23. A vehicle speed limiting apparatus, comprising: a user interface having input means for setting, changing, and locking a maximum allowable speed (V_MA ) of the vehicle; and a software control module having a memory for storing said V_MAX input by the user and having a speed control function, said software control module operatively connected to a vehicle's speed reduction means. 5

24. The apparatus of claim 23, wherein said software module further includes an emergency override function which selectively disables said speed control function for a specified period of time.

l(j 25. The apparatus of claim 23, wherein said speed control function includes preset instructions and an executable program which allow a driver to exceed V_MAX f°^{r a} specified period of time before reducing the speed of the vehicle to V_MAX by employing said speed reduction means.

15 26. The apparatus of claim 25, wherein said speed control function prevents the vehicle driver from exceeding V_MAX f°^{r a} specified period of time when the vehicle has been slowed to or below V_MAX subsequent to a period of time in which the vehicle's speed has been exceeding V_MAX-

20 27. The apparatus of claim 26, wherein said speed control function prevents the vehicle driver from exceeding V_MAX more than a specified number of times in a specified period of time.

28. The apparatus of claim 26, wherein said software module further includes an 25 emergency override function which selectively disables said speed control function for a specified period of time.

29. The apparatus of claim 25, wherein said software module further includes an emergency override function which selectively disables said speed control function for a

30 specified period of time.

30. The apparatus of claim 25, wherein said speed control function prevents the vehicle driver from exceeding V_MAX ^{more man a} specified number of times in a specified period of time.

31. The apparatus of claim 24, wherein said speed control function prevents the vehicle driver from exceeding V_MAX more than a specified number of times in a specified period of time.

32. A vehicle speed limiting apparatus for permitting an authorized user to set, change, and lock a maximum allowable speed for the vehicle and simultaneously allowing the driver of the vehicle to exceed the maximum allowable speed for a specified period of time before said apparatus reduces the vehicle speed to the selected maximum allowable speed, said apparatus comprising: a user interface, said user interface including input means for entering a pass code and at least one maximum speed setting (V_MAX) f°^r limiting excessive vehicle speed; vehicle speed sensing means capable of sensing vehicle speed and generating a vehicle speed signal; a software control module in electronic communication with said user interface and said vehicle speed sensing means, said software control module having a memory for storing the input of said maximum speed setting and a speed control function comprising an executable program responsive to said vehicle speed signal and said maximum speed setting and having a first preselected instruction specifying the length of time, T_f, equal to or greater than zero seconds, during which said speed control function delays before taking action to effect vehicle speed reduction; and vehicle speed reduction means in operative connection with said software control module.

33. The vehicle speed limiting apparatus of claim 32, wherein said speed control function includes a first abuse control function, said first abuse control function comprising: a first timer (t_fc) that begins counting when an overspeed condition is detected and stops counting when said T_f length of time is reached; a second preset instruction which specifies the length of time, T_Rb after correcting an overspeed condition that said speed limiting apparatus acts as an absolute governor; and a second timer (t_Rlc) that commences counting when said first timer has reached a time greater than or equal to T_f and the overspeed condition has been fully corrected by reducing vehicle speed to or below V_M^, and wherein said second timer stops counting when said T_R1 period of time has been reached.

34. The vehicle speed limiting apparatus of claim 36, wherein said speed control function further includes a second abuse control function comprising: a third preset instruction, said third preset instruction specifying the maximum number of times (R_MAX) that the speed control function can be reset after correction of an overspeed condition to enable the user to exceed VMAX; a fourth preset instruction which specifies the period of time (T^) during which no more than R_MAX number of resets may occur; and a counter variable, c_m, that equals the number of resets that occur in said previous T^ period of time.

35. The vehicle speed limiting apparatus of claim 34, wherein said input means includes an emergency override button, and wherein said software module includes an emergency override function whereby a user may selectively override said speed control function by pressing said emergency override button.

36. The vehicle speed limiting apparatus of claim 35, wherein said emergency override function disables said speed control function for a specified period of time (T_E), wherein during said specified period of time the vehicle will respond to all driver vehicle speed inputs, and wherein after said specified period of time has elapsed, said emergency override function re-enables full operation of said speed control function.

37. A method of limiting the speed of a vehicle, said method comprising the steps of: (a) providing a vehicle speed limiting apparatus having user interface with input means for entering a pass code which enables the entry of at least one maximum speed setting (V_MAX) for limiting excessive vehicle speed; vehicle speed sensing means capable of sensing vehicle speed and generating a vehicle speed signal; a software control module in electronic communication with the user interface and the vehicle speed sensing means, the software control module having a memory for storing the input of the maximum speed setting and a speed control function comprising an executable program responsive to the vehicle speed signal and the maximum speed setting and having a first preselected instruction specifying the length of time, T_f, equal to or greater than zero seconds, during which the speed control function delays before taking action to effect vehicle speed reduction; and vehicle speed reduction means in operative connection with said software control module;

(b) entering a pass code to enable entry of at least one maximum speed setting; and

(b) entering at least one maximum speed setting.

38. The method of claim 37, wherein the speed control function includes a first timer

(t_fc) that begins counting when an overspeed condition is detected and stops counting when said T_f length of time is reached; a second preset instruction which specifies the length of time, T_R1, after correcting an overspeed condition that said speed limiting apparatus acts as an absolute governor; and a second timer (t_Rlc) that commences counting when said first timer has reached a time greater than or equal to T_f and the overspeed condition has been fully corrected by reducing vehicle speed to or below the selected maximum speed setting and wherein said second timer stops counting when said T_R1 period of time has been reached; and wherein said method includes the further step of entering an authorized pass code prior to step (b) to enable input of the maximum speed setting.