Vehicle Headlights Research Articles

Autonomous Led Street Lights Based On Hybrid Renewable Sources

In this artical, the arrangement of solar photovoltaic (PV)/Wind energy system is used for power generation. During day time, solar radiation falls on the panel, and then the power can be produced. During night time, due to the Emission of photons from the vehicle headlight, the power is produced from the solar PV panel. The Wind Turbine is used to generate electricity from the rotation of the wind blade due to the movement of vehicles by Vertical Axis model. The output of the solar and wind system fed into Buck-Boost converter to high voltage level. The simple P&O control method is used to pathway the operating point of the system at which highest power can be obtained. The Power obtained from different sources is connected to the dc bus in parallel connection. Here the energy required for the load to be taken from the dc bus and excess power will be stored in a battery and also insufficient power, the battery will discharge the power to load. The model of a structure is developed in MATLAB- SIMULINK.

ViLDAR—Visible Light Sensing-Based Speed Estimation Using Vehicle Headlamps

The introduction of light emitting diodes (LED) in automotive exterior lighting systems provides opportunities to develop viable alternatives to conventional communication and sensing technologies. Most of the advanced driver-assist and autonomous vehicle technologies are based on Radio Detection and Ranging (RADAR) or Light Detection and Ranging (LiDAR) systems that use radio frequency or laser signals, respectively. While reliable and real-time information on vehicle speeds is critical for traffic operations management and autonomous vehicles safety, RADAR or LiDAR systems have some deficiencies especially in curved road scenarios where the incidence angle is rapidly varying. In this paper, we propose a novel speed estimation system so-called the Visible Light Detection and Ranging (ViLDAR) that builds upon sensing visible light variation of the vehicle's headlamp. We determine the accuracy of the proposed speed estimator in straight and curved road scenarios. We further present how the algorithm design parameters and the channel noise level affect the speed estimation accuracy. For wide incidence angles, the simulation results show that the ViLDAR outperforms RADAR/LiDAR systems in both straight and curved road scenarios.

On impact of vehicle headlights contamination with products of road chemical deicing agents upon pedestrian visibility on unlit roads

The goal is to determine consistent patterns that characterize the impact of vehicle headlamps contamination caused by products of chemical deicing agents treatment (PCDAT) used on the roads on the driver’s ability to see pedestrians on unlit roads. The analysis of theoretical works devoted to the impact of vehicle headlamps contamination with PCDAT upon their lighting the road was carried out. The authors conducted experimental studies of the process of contaminating vehicle headlights with PCDAT used on roads in winter under the real traffic conditions as well as measurements of luminous intensity of the contaminated headlights. Experimental studies of a pedestrian’s visibility on the side of a dark unlit road under the conditions of headlights contaminated with PCDAT were carried out. The authors developed the procedure of experimental studies to measure the distance of pedestrian visibility on a dark road with passing and driving beam headlights. The patterns that characterize the impact of vehicle headlamps contamination caused by PCDAT upon the driver’s ability to see pedestrians on unlit roads were determined. The results of the experiments are presented as tables, graphs and equations reflecting the new data. They relate to the consistent patterns of the impact of vehicle headlamps contamination caused by PCDAT on the driver’s ability to see pedestrians on an unlit road side in winter. The graphs allow analyzing the influence of vehicle headlamps contamination with PCDAT upon the driver’s ability to see pedestrians on the side of unlit roads in winter.

Temperature Rise Effects on Dynamic Resistances for Laser Diodes With a Wavelength of 450 nm for Vehicle Headlight Applications

In this paper, a laser headlight power converter (LHPC) was developed to drive the InGaN-based blue beam laser diode (BBLD). The LHPC was composed of the four–switch step-up step-down converter (FSSUSDC), the FSSUSDC controller, and the current error compensator (CEC). When the BBLD dynamic resistance was increased under the high ambient air temperature, the FSSUSDC operated in the step-down mode, and the CEC employed the proportional-integral control, the BBLD driving current exhibited an ignition current spike, which could destroy the semiconductor material of the BBLD, resulting in optical output power decay. Therefore, a new four-gradation gain (FGG) control method was proposed to mitigate the ignition current spike of the BBLD. This paper presented the BBLD temperature characteristic, an analysis of the LHPC ignition current, a CEC compensation design, and an analysis and design of the FGG control.

Adaptive Lightning System for Vehicle Protection

This paper presents an adaptive lightning system for vehicle protection. More specifically the present paper relates to an adaptive lightning system for vehicle protection during night times when the light intensity is too high. It comprises of a photo diode for detecting an incoming high intensity of light of vehicle during night. In most of the cases the night accident is due to the mistake of a driver who uses headlight instead of dippers, when another vehicle is coming from opposite side of road. Due to heavy traffic at night times there is a large number of road accidents because of the intense light of approaching vehicle. Therefore, this paper proposes an automatic controlling of headlights of vehicles by just turning the car steering, during night time and allows the driver to comfortably concentrate on driving.

Effect of vehicle swiveling headlamps and highway geometric design on nighttime sight distance

Sight distance is a fundamental factor in the design of highways as it determines their operational and safety performance, particularly in nighttime. Vehicles are increasingly being equipped with driving assistance systems such as adaptive frontlighting systems, from which potential safety benefits can be derived. One of the main capabilities of adaptive headlights is controlling headlamp swiveling when driving on horizontal curves to light up a greater section of the roadway ahead. In this study, the vehicle headlight beam was recreated to simulate swiveling systems that adapt the headlight beam to the highway geometry. Diverse horizontal spread angle values were assumed for the headlight lighting pattern. Based on horizontal curvature, a total of 24,663 mathematical functions that control the headlight swiveling angle were simulated. Next, headlight sight distance (HSD) was estimated on a 3D virtual model of an in-service highway, under assumptions of fixed and swiveling headlamps. Two types of algorithms were proposed for the swiveling headlights, one based on the trajectory curvature and another one predictive. The sets of HSD results were then analyzed and compared, the effects of the swiveling headlights on HSD being quantified along the highway section studied. In addition, the performance of diverse swiveling headlights was analyzed under different 3D highway alignment combinations. Finally, the robustness of the proposed procedure was validated.

Headlight recognition for night-time traffic surveillance using spatial–temporal information

Vehicle headlights are the important objects especially in the application of night-time traffic surveillance. A common problem of this task is the similarity between the headlights and their reflections on the road. This paper proposes a novel algorithm to construct 3D motion trajectories of headlights and their reflections on the road using both spatial and temporal information. 3D structure tensors are utilized as shape features for recognizing the headlights in various traffic views. Experimental results show that the proposed method performs better than traditional approaches (about 10 $$\%$$) in terms of the F1 score.

Photometric Properties of Retroreflective Materials in Dependence on their Structure and Angle of Illumination

The purpose of high visibility products is to reflect light at a low angle towards the source, such as vehicle headlights. The article presents measurements of the photometric properties of selected retroreflective materials made either of microlenses on a textile base or microprisms on a polymer base. The effects of the structure of the textile and polymer layers on the photometric properties of high visibility materials is analysed and the test methods applied are described.

Safety effects of street lighting on roadway segments: Development of a crash modification function

Objective: Nighttime crashes are overrepresented on the U.S. highway system. Roadway lighting, which provides additional visibility by supplementing vehicle headlights, has been identified as an effective countermeasure to improve nighttime safety. However, the existing literature does not provide a thorough understanding of the effects of street lighting photometric characteristics on nighttime crash occurrence on roadway segments. This study aimed to investigate the relationship between lighting photometric measures and nighttime crash risk on roadway segments and develop a crash modification function/factor (CMF).Methods: The research team collected horizontal illuminance data on 440 roadway segments between 2 successive signalized intersections in Florida for 2012–2014 and matched 4 years of nighttime and daylight crash data (2011–2014). Random parameter negative binomial models were estimated for both nighttime and daylight crash frequencies. The expected night-to-day crash odds ratio, as an equivalent of CMF, was derived from the fitted models with the correction of estimation variances. The confidence intervals (CIs) of the developed CMF were estimated using the Cox method.Results: The coefficient of the mean of horizontal illuminance is significantly negative in the nighttime model. The coefficients of the standard deviation of horizontal illuminance are significantly positive and normally distributed in both the nighttime and daylight models. The significance of the standard deviation in the daylight model captures the confounding effects—a high standard deviation correlates with high traffic exposures, poor safety design standards, and low maintenance quality. The CMF based on the expected daylight-to-day odds ratio was developed as an exponential function of the increments and the increment squares of the mean and the standard deviation of horizontal illuminance. Its 95% CIs indicate that the CMF is almost significant over the whole range. Other significant variables contributing to nighttime crash risk include annual average daily traffic, truck percentage, segment length, access density, undivided roads, and urban/city limits.Conclusions: Horizontal illuminance characteristics have a significant impact on nighttime crash risk on roadway segments. An increase in the mean of horizontal illuminance, indicating an improvement in average lighting level, tends to decrease nighttime crash risk; an increase in the standard deviation, representing a poor uniformity of lighting pattern on a roadway segment, is more likely to raise nighttime crash risk. Because the 2 measures are strongly correlated in a low mean range (<0.44 fc), the 2 photometric measures need to be considered together to interpret the safety effects of lighting patterns. The standard deviation shows better performance in measuring lighting uniformity on a roadway segment than the traditional ratios (max-to-min and mean-to-min). However, a new photometric measure is needed to capture the true lighting pattern influencing driver vision at night.

Correction and Evaluation for Color Aberration on the Cut-off Line of a Vehicle Headlamp

Correction and Evaluation for Color Aberration on the Cut-off Line of a Vehicle Headlamp

High-resolution headlamps – technology analysis and system design

Abstract High-resolution vehicle headlamps are the technological way to intelligently illuminate the traffic area to increase safety and comfort. For the technical realization of these headlamps, different technologies come into question, which are the subject of intensive research at universities and among the manufacturers. We present an overview of the possible technologies and analyze their potential for use in high-resolution headlamps. Furthermore, we explain how the design of the optical system for the different technologies can be made. Another part of this paper is the comparison of published prototypes of high-resolution headlamps and the compilation of key properties.

PCANet-Based Convolutional Neural Network Architecture for a Vehicle Model Recognition System

Vehicle model recognition plays a crucial role in intelligent transportation systems. Most of the existing vehicle model recognition methods focus on locating a large global feature or extracting more than one local subordinate-level feature from a vehicle image. In this paper, we propose the principal component analysis network-based convolutional neural network (PCNN) and pinpoint only one discriminative local feature of a vehicle, which is the vehicle headlamp, for vehicle model recognition. The proposed model eliminates the need for locating and segmenting the headlamp precisely. In particular, PCNN ascertains the effectiveness of both principal component analysis and CNN in extracting hierarchical features from a vehicle headlamp image and also reducing the computational complexity of the traditional CNN system. To further enhance the training procedure while still keeping the discriminative property of the network, the fully connected layer is updated by backpropagation optimized with stochastic gradient descent. The proposed method is validated using a data set that comprises 13 300 training images and 2660 testing images, respectively. The model is robust against various distortions. Experiments show that PCNN outperforms state-of-the-art techniques with an average accuracy of 99.51% over 38 vehicle makes and models using the PLUS data set. In addition, the effectiveness of the proposed method is also validated using the public CompCars data set, achieving 89.83% accuracy over 357 vehicle models.

Wireless Sensing using Vehicle Headlamps for Intelligent Transportation Systems: Proof of Concept

Vehicular communication and sensing technologies are mainly based on the conventional radio frequency (RF) or laser technologies. These systems suffer from several issues such as RF interference and poor performance in scenarios where the incidence angle between the speed detector and the vehicle is rapidly varying. Introducing a new sensing technology will add diversity to these systems and enhance the reliability of the real-time data. In this study, we investigate our speed estimation sensing system named “Visible Light Detection and Ranging (ViLDAR)”. ViLDAR utilizes visible light sensing technology to measure the variation of the vehicle's headlamp light intensity and estimate the vehicle speed. The measurement settings of the ViLDAR experiments are presented. The preliminary results obtained in the real-world environment/setting are promising when compared to the simulations. Additional measurements using the ViLDAR prototype will be conducted under different conditions and scenarios to further optimize the system.

Depressing Start-Up Current Overshoot for a Laser Headlight Driver in High-Temperature and Forward Voltage Drift Conditions

High-optical-output-power laser diodes (HOO-PLDs) are a new option for the next-generation vehicle headlights. This paper develops a laser headlight driver (LHD) combining a safety standard circuit, dc–dc converter, and feedback controller. The dc–dc converter topology is a two-switch two-diode buck–boost converter (TSTDBBC), which could be operated in both step-up or step-down conversion modes for variable battery voltage input to the LHD, enabling the driving voltage and current of the HOOPLD to be obtained from the TSTDBBC output. Because the operating ambient temperature (OAT) can cause forward voltage drift in the HOOPLD, the feedback controller could be used to stabilize the driving current to cope with forward voltage drift. Moreover, in the start-up phase, a current overshoot occurs when the TSTDBBC operation changes from the constant-voltage output mode to the constant-current output mode. This can be further aggravated when HOOPLDs operate under a high OAT. Therefore, proportional switching proportional-integral control technology was applied to the current-feedback controller to depress the current overshoot, enabling the driving current of the HOOPLDs to be maintained at the rated specification to ensure operating lifespan. Complete design procedures are presented. Simulations and experimental results validate that the proposed control technology is effective for solving the ignition problem.

Examination of the vehicle light intensity in terms of road traffic safety: a case study

Road transport is an essential part of modern life. It brings with itself, besides the desired effects, negative aspects as well. Negative aspect is not only the emissions production but also the traffic accidents occurrence even with tragic consequences. In proportion to traffic intensity, accidents during decreased visibility represent a significant share. A driver has a limited source of information at this time, since only vehicle headlights illuminate the runway and its surroundings. However, these do not only illuminate the roadway ahead of the vehicle, but part of the emitted light also falls into the drivers’ eyes of vehicles in the opposite direction. Thus, the eyes of such glared drivers worse recognize details, or lose the ability to see at all, i.e. vision ability. The level of vision loss depends on the light intensity that falls into the drivers’ eyes in the opposite direction. This light intensity is related not only to the correct headlights alignment (setting) but also to their design. In this paper, three generations of headlights in terms of the light intensity falling into the driver’s eyes of the vehicle in the opposite direction are compared. The headlights alignment of the examined vehicles was checked prior to measurements in accordance with the manufacturer's requirements. Given the fact that intensity of the emitted light is also related to the age of the used source, they have been replaced by the new ones. For the reason of objectivity, examination was performed at night at the New Moon phase, thus it did not light up. The starlight also did not affect the measurement results because it was cloudy, but it did not rain. There were no artificial sources of light near the measuring point..

An examination of the increases in pedestrian motor-vehicle crash fatalities during 2009–2016

IntroductionPedestrian fatalities increased 46% in the United States during 2009–2016. This study identified circumstances under which the largest increases in deaths occurred during this period. MethodAnnual counts of U.S. pedestrian fatalities and crash involvements were extracted from the Fatality Analysis Reporting System and General Estimates System. Poisson regression examined if pedestrian fatalities by various roadway, environmental, personal, and vehicle factors changed significantly during 2009–2016. Linear regression examined changes over the study period in pedestrian deaths per 100 crash involvements and in horsepower per 1000 pounds of weight among passenger vehicles involved in fatal single-vehicle pedestrian crashes ResultsPedestrian deaths per 100 crash involvements increased 29% from 2010, when they reached their lowest point, to 2015, the most recent year for which crash involvement data were available. The largest increases in pedestrian deaths during 2009–2016 occurred in urban areas (54% increase from 2009 to 2016), on arterials (67% increase), at nonintersections (50% increase), and in dark conditions (56% increase). The rise in the number of SUVs involved in fatal single-vehicle pedestrian crashes (82% increase) was larger than the increases in the number of cars, vans, pickups, or medium/heavy trucks involved in these crashes. The power of passenger vehicles involved in fatal single-vehicle pedestrian crashes increased over the study period, with larger increases in vehicle power among more powerful vehicles. ConclusionsEfforts to turn back the recent increase in pedestrian fatalities should focus on the conditions where the rise has been the greatest. Practical applicationsTransportation agencies can improve urban arterials by investing in proven countermeasures, such as road diets, median crossing islands, pedestrian hybrid beacons, and automated speed enforcement. Better road lighting and vehicle headlights could improve pedestrian visibility at night.

Start-Up Current Spike Mitigation of High-Power Laser Diode Driving Controller for Vehicle Headlamp Applications

A high-power laser diode driving controller (HPLDDC), which incorporates the power converter with the feedback controller, was developed and implemented in this paper. The synchronous buck–boost converter (SBBC) was the topology of the power converter; the SBBC could be operated in step-up or step-down mode in accordance with variable on-board battery voltage inputs into the HPLDDC. Moreover, the feedback controllers were equipped with a current-loop controller (CLC) and a voltage-loop controller (VLC); the VLC was employed to regulate the SBBC output voltage to drive and start-up the high-power laser diode (HPLD). The CLC was used to regulate the SBBC output current to supply a constant-current driving the HPLDs. During the start-up transient phase, when the SBBC output mode is changed from the constant-voltage to the constant-current, a start-up current spike occurs that can destroy the semiconductor material of the laser diode. However, few studies have discussed methods of coping with this problem. Therefore, this study proposed a proportional-integral associating proportional (PIAP) control technology, which can be applied to the CLC for the start-up current spike mitigation. Complete designs and analyses are presented in this paper. Simulations and experiments validate that the PIAP control method is effectual to solve the start-up current spike.

Conclusive Review on Adaptive Headlight System for Four-Wheeler Frontlight using Stepper Motor

Major road mishaps occur at night on account of curve roads and glare caused from the headlights of incoming vehicles. Night time driving with conventional headlamps is particularly unsafe: only 25% of the driving is done at night but 55% of the driving accidents occur during this period. The existing conventional light system does not provide illumination in the right direction and at the precise angle. Due to this constrain, a need to understand an alternative technology solution. Adaptive front lighting system (AFS) helps improve driver’s visibility at night time hence achieving enhance safety. The objective of this work is to design and build an AFS Prototype. From the results, it is concluded that the headlamp swings in horizontal direction by sensing steering angle and vertical by sensing distance between subject vehicle and next vehicle. Accuracy, reliability and availability of the components were few considerations during the conceptualization stage.

Conclusive Review on Adaptive Headlight System for Four-Wheeler Frontlight using Stepper Motor

Major road mishaps occur at night on account of curve roads and glare caused from the headlights of incoming vehicles. Night time driving with conventional headlamps is particularly unsafe: only 25% of the driving is done at night but 55% of the driving accidents occur during this period. The existing conventional light system does not provide illumination in the right direction and at the precise angle. Due to this constrain, a need to understand an alternative technology solution. Adaptive front lighting system (AFS) helps improve driver’s visibility at night time hence achieving enhance safety. The objective of this work is to design and build an AFS Prototype. From the results, it is concluded that the headlamp swings in horizontal direction by sensing steering angle and vertical by sensing distance between subject vehicle and next vehicle. Accuracy, reliability and availability of the components were few considerations during the conceptualization stage.

Illuminance and heat transfer characteristics of high power LED cooling system with heat sink filled with ferrofluid

In the case of a high power LED (light emitting diode) cooling system using the ferrofluid, the illuminance characteristics, including the illuminance and the illuminance efficacy, as well as the heat transfer characteristics, including the temperature and the thermal resistances, were experimentally investigated under various input voltages and magnetic fields and compared with air and water working fluids. The temperatures of the LED surface, the heatsink surface, and the LED junction of the high power LED cooling system with ferrofluid all increased with a rise in the input voltages. The illuminance of the high power LED cooling system with the ferrofluid also increased with increases in the input voltage until an elapsed time of 1200 sec, but the illuminance of the high power LED cooling system dramatically decreased at 19.3 V, due to the increased power consumption. The junction temperature and the illuminance efficacy of the high power LED cooling system with the magnet decreased at all input voltages by 9.7% and increased by 6.9%, respectively, compared to those without the magnet. The high power LED cooling system with the ferrofluid at an elapsed time of 3600 sec showed 67.5% and 66.1% higher illuminances than those of the air and the water, respectively. As a result, the cooling and optical performances could be improved using the ferrofluid as the cooling liquid, and could be further enhanced by applying the external magnetic field. In addition, the designed LED cooling system with the thin fin heat sink filled with the ferrofluid is suggested as a potential vehicle headlamp considering the illuminance for visibility and effective cooling.