Communications: electrical – Land vehicle alarms or indicators – External alarm or indicator of movement
Reexamination Certificate
1998-10-23
2001-04-03
Tong, Nina (Department: 2736)
Communications: electrical
Land vehicle alarms or indicators
External alarm or indicator of movement
C340S467000, C340S479000, C340S463000, C340S464000, C340S468000
Reexamination Certificate
active
06211780
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention is a colour coded rear lighting system for motor vehicles.
DISCUSSION OF THE RELATED ART
There are prior art which try to indicate the rate of the deceleration of a vehicle without relying on mechanical deceleration detectors [U.S. Pat. No. 5,481,243 and GE Pat. No. DE 4236395 A1]. One of the outstanding features of the present invention is that it measures speed of vehicle on which it is installed by internationally standardized unit (eg. km/h) and flashes a light when speed of the vehicle is varied by a standardized speed difference.
SUMMARY OF THE INVENTION
Dynamic Traffic Light takes the place of centre high mounted stop lamps on motor vehicles, since the brake lighting system presently used on vehicles is too primitive and too static.
It is primitive because it has a single and simple function which does not precisely reflect the changes of speed of leading vehicles. If leading driver simply reduces pressing the gas pedal and does not brake at all, speed of his/her vehicle drops. In many cases this decrease in speed has significant consequences but it is not informed to following drivers by any light. Therefore, the brake lighting system currently used in vehicles is not informative enough to following drivers and it is not sufficiently appropriate for a goal so important as to prevent traffic crashes.
The brake lighting system which is used at the present time on motor vehicles is static because though it signifies deceleration when driver applies brake, it does not indicate to following drivers how fast the speed of a leading vehicle is reduced. For example, if a car is travelling at certain speed, whether the driver of this car just touches the brake pedal or he/she presses the brake pedal rigorously for swift deceleration, a red light is simply turned on. If leading car is stopped or it has low speed, and its driver is not pressing the brake pedal, there is no indication from a distance to following driver (who may have high speed) that the leading car is actually stopped or it has low speed, unless following vehicle advances perilously closer to leading one. If leading car is stopped with its brake lights on, from a fairly far distance it is not immediately evident to following drivers whether the leading car is stopped or it is in motion. In the latter case, there is no indication about the range of speed of leading car. So following drivers should approach the leading car more and then react.
“Lave (1987) ran a number of cross-section regressions on state data.
In this invention orange, red and green lights are used to dynamically coordinate the variation of speed of vehicles by providing highway information. At every moment, Dynamic Traffic Light of leading cars help following drivers who just look at the leading cars (on all lanes) from a distance, to realize:
a) Whether leading cars travel with a constant speed or they are accelerating or decelerating
b) If leading cars are accelerating or decelerating, how fast the speed of these cars is changed.
c) The range of speed of leading cars.
More precisely, Dynamic Traffic Light performs 12 well-defined functions. In order to explain them, I first define the following:
i) One unit of speed=a standardized speed difference or other words, a selected multiple of the internationally standardized unit (eg. km/h). The unit of speed for the operation of Dynamic Traffic Light is selected to be 1 km/h for the occurrence of the first flash of the orange and red lights. The unit of speed is selected to be 3 km/h for the occurrence of the subsequent flashes of the orange and red lights as well as for the occurrence of the flashes of the green light(s).
ii) Reference speed=Speed at which a flashing of any light occurs
iii) First flash=Flash of orange or red light which occurs after 1 km/h or more is reduced from reference speed.
iv) Constant speed=[Mathematically], speed whose domain is:
(reference speed−1 km/h, reference speed+3 km/h) so that constant speed can fluctuate in the mentioned domain, and yet no flashing occurs.
v) Last flash=Flashing of any light after which speed becomes constant.
The frequency at which green, red or orange lights flash help following drivers to immediately perceive how fast the speed of a leading car increases and more importantly, how fast the speed of a leading car decreases. Consequently, following drivers can react more appropriately to the alterations of speed of leading car.
It seems that when unit of speed is chosen to be 3 km/h, 10 flashes per second is reasonable as maximum rate of flashing by any light of Dynamic Traffic Light. For example, if a leading driver brakes so hard to reduce the speed of his/her car 30 km/h or more per second, then 10 flashes per second of red light is fast enough to reflect drastic deceleration of leading car.
If speed X km/h is increased by Y km/h, so that the Y km/h is less than one unit of speed, green light LG
3
does not flash as it is supposed to, since (X+Y) km/h is still considered as constant speed. If speed (X+Y) km/h is reduced by one unit, red or orange lamps do not flash, because flashing occurs only if one unit of speed is added to or reduced from reference speed. So, in the above example, speed should be first diminished by Y km/h and then it should be further reduced by one unit to cause the first flash of orange or red lights to happen. But the first flash of orange light in particular, is the most important to reduce the reaction time of following drivers. Thus Dynamic Traffic Light is designed so that the first flash of red or orange lights occur as soon as reference speed is reduced by 1 km/h.
This assures that the first flash of orange or red lights occur after one unit or less decrease in constant speed. The subsequent flashes of red or orange light occur after at least one unit of speed is reduced from negative reference speed (speed at which a flash of red or orange occurred and continues to decelerate).
An extreme case with the functions of Dynamic Traffic Light is when a car equipped with such traffic light loses traction and its tires spin faster than the actual speed of car. This situation is common when a car is accelerated from rest position on snow or ice. The result is false flashes of green light since these flashes are supposed to reflect increase in speed of car. In order to prevent such incorrect flashes, Dynamic Traffic Light is designed so that when speed that is lower than 32 km/h increases, green light does not flash. But if this low speed is reduced, orange or red lights flash. Evidently, false flashes of green light never occur with cars equipped with a traction control system.
Accidents occur when speed variations happen. Flashes of Dynamic Traffic Light arise when reference speed is changed at least by one unit. The first flash of orange or red light can be set to occur when reference speed is reduced by 1 km/h or other words, when speed is reduced by 1 km/h or more.
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