FIELD OF THE INVENTION

[0001] The invention generally relates to traffic safety and in particular to road engineering to improve driver alertness.

BACKGROUND

[0002] According to the United States National Highway Traffic Safety Administration, 5,977 pedestrians were killed in traffic crashes in the United States in 2017. The World Health Organization estimates that, each year, more than 270 000 pedestrians lose their lives on the world’s roads. Globally, pedestrians constitute 22% of all road traffic fatalities, and in some countries this proportion is as high as two thirds of all road traffic deaths. Millions more suffer non-fatal injuries, some of whom are left with permanent disabilities. The traffic risks to pedestrians are all the more troublesome considering that many communities are working to increase walkability of neighborhoods as part of their efforts to achieve sustainability. [0003] Some solutions for displaying pedestrian warnings inside cars have been proposed, such as providing such warnings on heads-up displays (HUDs). Such systems generally require that in-vehicle systems be configured to communicate with external pedestrian detection systems.

[0004] Better methods of warning drivers could reduce injury and death.

SUMMARY

[0005] Embodiments of the present invention provide a system and methods for improving traffic safety. In particular, embodiments provide a system for alerting drivers that a pedestrian may cross a street at a street crossing that includes: one or more presence detection sensors, configured to detect a pedestrian before the pedestrian enters a path of traffic in the street; and a projection system, including a visible signal projector, one or more processors, and memory storage, the memory storage including instructions. The instructions when executed by the one or more processors implement steps that may include: receiving a signal from the one or more presence sensors and responsively projecting a visible signal that appears to a driver of a vehicle to be in the path of traffic, at a position above the street crossing.

[0006] The presence detection sensors may include a pressure sensor configured to detect a weight of a pedestrian and placed where pedestrians may step before entering the path of traffic. The pressure sensor may be a load cell, and receiving the signal from the one or more presence sensors may include receiving a signal indicative of a change of pressure.

[0007] The presence detection sensors may include one or more of a passive infrared sensor, an ultrasonic presence sensor, and a microwave presence sensor. The presence detection sensors may additionally or alternatively include one or more motion detection sensors configured to detect a change in electromagnetic radiation of a pedestrian and placed where pedestrians may step before entering the path of traffic.

[0008] The presence detection sensors may additionally or alternatively include one or more motion detection sensors to detect a change in a reflected ultrasound level due presence of a pedestrian and placed where pedestrians may step before entering the path of traffic. [0009] In some embodiments, the street crossing is a marked crosswalk, and the visible signal is projected over the marked crosswalk.

[0010] In further embodiments, projecting the visible signal includes monitoring a traffic light and only displaying the visible signal when the traffic light is green. [0011] The system may further include a water, fog or haze generator producing a water or aerosol screen onto which the visible warning signal is projected to form an image. The image may be a 3D image.

[0012] Projecting the visible signal may include projecting the visible signal only when a vehicle is approaching the street crossing.

[0013] Further embodiments of the present invention provide a computer-based method for alerting drivers that a pedestrian may cross a street at a street crossing. The method may include receiving a signal from the one or more presence sensors indicative of a pedestrian at a street crossing, and, responsively, projecting a visible signal that appears to a driver of a vehicle to be in the path of traffic, at a position above the street crossing.

BRIEF DESCRIPTION OF DRAWINGS

[0014] For a better understanding of various embodiments of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings. Structural details of the invention are shown to provide a fundamental understanding of the invention, the description, taken with the drawings, making apparent to those skilled in the art how the several forms of the invention may be embodied in practice. In the accompanying drawings:

[0015] Figs. 1 and 2 are schematic illustrations of a system for improving traffic safety, according to some embodiments of the present invention; and,

[0016] Fig. 3 is a flow diagram of a process for improving traffic safety, according to some embodiments of the present invention.

B DETAILED DESCRIPTION

[0017] It is to be understood that the invention and its application are not limited to the system and methods described below or to the arrangement of the components set forth or illustrated in the drawings, but are applicable to other embodiments that may be practiced or carried out in various ways.

[0018] Figs. 1 and 2 are schematic illustrations of a system 20 for improving traffic safety, according to some embodiments of the present invention.

[0019] As illustrated in the figures, a pedestrian 22 approaches or enters a street crossing, such as a crosswalk 24. Because the pedestrian, standing or moving at the side of a street, may not catch the attention of a vehicle driver approaching the crosswalk, the pedestrian may be at some risk of being hit by the vehicle, even if the pedestrian has the legal right-of-way. To reduce this risk, embodiments of the present invention provide a system and methods for alerting drivers (who might be otherwise distracted) to the pedestrian's presence, thereby reducing the risk.

[0020] One or more sensors 26 are placed at positions near the street to detect the pedestrian's presence. The sensors may be pressure sensors installed under a surface covering 28. The load cells may be any of a variety of pressure and vibration sensors, such as strain gauges, or hydraulic or pneumatic sensors. The positions at which the sensors 26 are placed are typically portions of sidewalks near crosswalks, such as street comers. The positions may also be at the sides of streets, including at the sides of streets that do not have pronounced sidewalks. Alternatively, or as an addition to pressure sensors, sensors 26 may be radiation, audio, or optical-based motion sensors, such as passive infrared (PIR) sensors, microwave sensors, or ultrasound motion detection sensors. These sensors sense a change in an electromagnetic or ultrasound level to determine presence of a pedestrian. [0021] Signals indicative of pressure changes or vibrations are transmitted from the sensors 26 to a controller 30, and may be installed in the vicinity of, or collocated with, the positions of the sensors 26. Some signal processing may be employed to filter the signals to determine that they are indicative of a pedestrian, rather than other disturbances, such as ground vibration from traffic.

[0022] If the controller 30 determines that a pedestrian is indeed the cause of the signal, the controller then initiates a procedure to provide a pedestrian warning signal to drivers that may be approaching the crosswalk. Such signals appear above the crosswalk, such that they provide an image in space above the crosswalk that is in a direct line-of-sight of a driver approaching the crosswalk.

[0023] In some embodiments, the processor operates two devices, a projector 32 and a liquid or vapor screen generator 34. The screen generator provides a water or vapor screen above the crosswalk onto which the projector casts a visual warning signal for drivers. The screen may be liquid, fog, or haze. The generator may be a heated fog machine having a fluid reservoir, an electric pump to eject the fog fluid, and a heater that vaporizes the fluid. The pump may have a variable speed to control the output of fog. Gas propelled fog machines may operate with a non-toxic gas, such as CO2 or nitrogen, to propel either mineral oil or a glycol-based fluid into a heater. The heater vaporizes the fluid/gas mixture, thereby creating a fog. The volume of gas used to propel the fluid may also be controlled.

[0024] Hereinbelow, the controller, the projector, and, optionally the screen generator are also referred to as a "projection system." In further embodiments, the projector and the controller are integrated into a single device. In some embodiments, the controller is integrated into a case including the projector. The controller, the screen generator and the projector may also be integrated into a single device, located at street level to pump or blow a screen above ground. Alternatively, the screen generator and some or all of the other devices, may be positioned above the crosswalk. Typically, the projector is positioned to direct an image at the generated screen, such that drivers see a reflection of the image in the screen. In some embodiments, the source of liquid for the screen generator (typically water) may be a fluid tank 38. The liquid, for fog and haze generators, may be a water and glycol-based or glycerin-based fluid, which is atomized by the generator. Liquid air or liquid nitrogen may be used when the generator is above the street level, as these gases first drop before the gas is dissipated, thereby providing a screen effect while dropping.

[0025] The projector 32 may be a laser projector. The projector may also be a holographic projector. The projector may be mounted above the crosswalk on a pole 36. Alternatively, as indicated in Fig. 2, there may be multiple projectors 32, which may be installed in the street, such that the body of each projector is mainly or completely under the surface, while the lens is exposed to project the warning signal. Alternatively, the projectors 32 may be place above the crosswalk, together with the screen generator as indicated in Fig. 1A.

[0026] In some embodiments, for example when the projector is a holographic projector, the warning signal may be a 3D virtual image 40, such as an image of a pedestrian in the crosswalk, as shown in Fig. 1. In further embodiments, the holographic projector is configured to project a holograph video, such that the warning signal may be a moving image, such as a pedestrian crossing the street.

[0027] In additional embodiments, as indicated in Fig. 2, two laser projectors may be positioned at different sides of the street and when operated provide a warning signal of crossed laser lights 42. [0028] If weather conditions permit, for example on humid nights or with a low fog, the warning signal may also be visible without the need for operating the water or vapor screen generator 34. It is to be understood that the crosswalk as described herein is any location along a street across which pedestrians may cross, and needn't only be locations that are designated as crosswalks, such as by painted patterns on the street.

[0029] Fig. 3 is a flow diagram of a process for improving traffic safety, according to some embodiments of the present invention. After system 20 is installed in the proximity of a crosswalk, one or more of the sensors at a step 102 may detect a pressure indicative of a human standing at the position of the sensor. A signal, such as a strain gauge voltage signal (typically amplified by a strain gauge amplifier), is transmitted to the controller 30 (step 104). At a step 106, the controller which filters the signal to determine that it is indicative of a human weight (for example 10 kg to 200 kg). The controller may also receive input from a traffic light controller to determine whether or not the pedestrian has the right-of-way, e.g., whether the pedestrian has a green light for crossing or whether there is a green light for vehicles to go through the crosswalk. In some embodiments, only if there is a pedestrian and if the pedestrian has the right-of-way, then at a step 108 the controller operates the projector to project a visual warning signal over the crosswalk, that is, a path of traffic, typically at an intersection. The visual warning signal may be, for example, an image of a person crossing the street or an image of a stop sign or roadblock. The controller may also be configured to provide additional warnings to the pedestrian, for example sounding an alarm signal if there is an approaching vehicle that is not slowing to a stop.

[0030] Computational aspects of system 20 and of process 100 may be implemented in digital electronic circuitry, or in computer hardware, firmware, software, or in combinations thereof. [0031] All or part of the system and process can be implemented as a computer program product, tangibly embodied in an information carrier, such as a machine-readable storage device or in a propagated signal, for execution by, or to control the operation of, data processing apparatus, such as a programmable processor, computer, or deployed to be executed on multiple computers at one website or distributed across multiple websites. Memory storage may also include multiple distributed memory units, including one or more types of storage media. Examples of storage media include, but are not limited to, magnetic media, optical media, and integrated circuits such as read-only memory devices (ROM) and random access memory (RAM). A computing system configured to implement the system may have one or more processors and one or more network interface modules. Processors may be configured as a multi-processing or distributed processing system. Network interface modules may control the sending and receiving of data packets over networks.

[0032] It is to be understood that the scope of the present invention includes variations and modifications thereof which would occur to persons skilled in the art upon reading the foregoing description and which are not disclosed in the prior art.