Icy Road Conditions Research Articles

Enhancing Autonomous Vehicle Safety in Cold Climates by Using a Road Weather Model: Safely Avoiding Unnecessary Operational Design Domain Exits

<div>This study investigates the use of a road weather model (RWM) as a virtual sensing technique to assist autonomous vehicles (AVs) in driving safely, even in challenging winter weather conditions. In particular, we investigate how the AVs can remain within their operational design domain (ODD) for a greater duration and minimize unnecessary exits. As the road surface temperature (RST) is one of the most critical variables for driving safety in winter weather, we explore the use of the vehicle’s air temperature (AT) sensor as an indicator of RST. Data from both Road Weather Information System (RWIS) stations and vehicles measuring AT and road conditions were used. Results showed that using only the AT sensor as an indicator of RST could result in a high number of false warnings, but the accuracy improved significantly with the use of an RWM to model the RST. ROC-curve analysis resulted in an AUC value of 0.917 with the AT sensor and 0.985 with the RWM, while the true positive rate increased from 67% to 94%. The study also highlights the limitations of relying on dashboard cameras to detect slippery driving conditions, as it may not be accurate enough to distinguish between, for example, wet and icy road conditions. As winter maintenance often prevents slippery roads, the vehicles often measured wet or moist roads, despite RST < 0°C. Our calculations indicate that the vehicle should be able to detect 93% of slippery occasions but the rate of false warnings will be as high as 73%, if using a dashboard camera along with the AT sensor. There are clear benefits of using a RWM to improve road safety and reduce the risk of accidents due to slippery conditions, allowing AVs to safely extend their time within their ODD. The findings of this study provide valuable insights for the development of AVs and their response to slippery road conditions.</div>

Quasi-experimental evaluation of municipal ice cleat distribution programmes for older adults in Sweden

IntroductionFall injuries caused by icy road conditions are a prevalent public health problem during winters in Sweden, especially in older populations. To combat this problem, many Swedish municipalities have distributed...

Ice cleat distribution programmes and ice cleat use among older adults: repeated cross-sectional evidence from 63 municipal interventions in Sweden

IntroductionIce cleats may help prevent ice-related falls in places with icy roads, but there is limited evidence about the association between ice cleat distribution and ice cleat use. Our study...

Evaluation of the design and implementation of municipal ice cleat distribution programs for the prevention of ice-related fall injuries among older adults in Sweden.

The risk for outdoor falls tends to increase during winter due to icy road conditions. Several Swedish municipalities have introduced programs that provide their senior citizens with a pair of ice cleats in an attempt to tackle this problem. In this paper, we perform a process evaluation to identify potential barriers to the success of these programs and analyze the logic of their design. We sent a survey to all 290 Swedish municipalities to collect data on the characteristics of ice cleat distribution programs. We also performed focus-group interviews with older adults to gain insight into their thoughts about ice cleat programs. We synthesized our data with existing literature on ice cleats and behavior change theory to populate a logic model to identify and analyze hidden assumptions and potential flaws using program theory analysis. On average, about 40% of the eligible population living in the intervention municipalities collected a pair of ice cleats. While we identified some other, but mostly minor, barriers to implementation, the main barrier appears to be a lack of scale (i.e., insufficient procurement and distribution of ice cleats), as 90% of all purchased ice cleats were eventually distributed. While previous research suggests that ice cleats can decrease injury risks if worn, we find that there is limited evidence on the effects of distribution on ice cleat use. Our interviewees emphasized the potential utility of ice cleats for staying safe and active during winter but stressed that ice cleats need to be user-friendly and of high-quality to increase the likelihood that a distribution program encourages behavior change. Existing ice cleat distribution programs appear to have reached a meaningful share of the targeted population. Additional research is required to assess their effects on ice cleat use and injury rates.

Identifying the Factors Contributing to the Severity of Truck-Involved Crashes in Shanghai River-Crossing Tunnel.

The impact that trucks have on crash severity has long been a concern in crash analysis literature. Furthermore, if a truck crash happens in a tunnel, this would result in more serious casualties due to closure and the complexity of the tunnel. However, no studies have been reported to analyze traffic crashes that happened in tunnels and develop crash databases and statistical models to explore the influence of contributing factors on tunnel truck crashes. This paper summarizes a study that aims to examine the impact of risk factors such as driver factor, environmental factor, vehicle factor, and tunnel factor on truck crashes injury propensity based on tunnel crashes data obtained from Shanghai, China. An ordered logit model was developed to analyze injury crashes and property damage only crashes. The driver factor, environmental factor, vehicle factor, and tunnel factor were explored to identify the relationship between these factors and crashes and the severity of crashes. Results show that increased injury severity is associated with driver factors, such as male drivers, older drivers, fatigue driving, drunkenness, safety belt used improperly, and unfamiliarity with vehicles. Late night (00:00–06:59) and afternoon rushing hours (16:30–18:59), weekdays, snow or icy road conditions, combination truck, overload, and single vehicle were also found to significantly increase the probability of injury severity. In addition, tunnel factors including two lanes, high speed limits (≥80 km/h), zone 3, extra-long tunnels (over 3000 m) are also significantly associated with a higher risk of severe injury. So, the gender, age of driver, mid-night to dawn and afternoon peak hours, weekdays, snowy or icy road conditions, the interior zone of a tunnel, the combination truck, overloaded trucks, and extra-long tunnels are associated with higher crash severity. Identification of these contributing factors for tunnel truck crashes can provide valuable information to help with new and improved tunnel safety control measures.

Time‐aware gated recurrent unit networks for forecasting road surface friction using historical data with missing values

An accurate road surface friction prediction algorithm can enable intelligent transportation systems to share timely road surface condition to the public for increasing the safety of the road users. Previously, scholars developed multiple prediction models for forecasting road surface conditions using historical data. However, road surface condition data cannot be perfectly collected at every timestamp, e.g. the data collected by on-vehicle sensors may be influenced when vehicles cannot travel due to economic cost issue or weather issues. Such resulted missing values in the collected data can damage the effectiveness and accuracy of the existing prediction methods since they are assumed to have the input data with a fixed temporal resolution. This study proposed a road surface friction prediction model employing a Gated Recurrent Unit network-based decay mechanism (GRU-D) to handle the missing values. The evaluation results present that the proposed GRU-D networks outperform all baseline models. The impact of missing rate on predictive accuracy, learning efficiency and learned decay rate are analyzed as well. The findings can help improve the prediction accuracy and efficiency of forecasting road surface friction using historical data sets with missing values, therefore mitigating the impact of wet or icy road conditions on traffic safety.

Freeway Truck Traffic Safety in Wyoming: Crash Characteristics and Prediction Models

The State of Wyoming experiences a high percentage of truck traffic along all its highways, especially Interstate 80 (I-80). The increased interactions between trucks and other vehicles have raised many operational and safety concerns. This paper presents a safety analysis and a development of safety performance functions (SPFs) along I-80, with a focus on truck crashes. Nine years of historical crash data in Wyoming (2008–2016) were used to observe the involvement of light, medium, and heavy trucks in crashes. Analysis of the major contributory factors showed that 54% of the total truck-related crashes occurred during icy road conditions and about 46% during snowy weather conditions, and approximately 45% involved driving too fast and driving in improper lane. The analysis also included segments with horizontal curves and vertical grades and their impacts on truck crashes. The crash rate analysis showed higher truck crash rate compared with total crash rate considering equal vehicle miles traveled as exposure. A zero-inflated negative binomial model was applied to develop Wyoming-specific SPFs for various truck crash types. The effects of traffic, road geometry characteristics, and weather parameters influencing different truck-related crashes were quantified from these models. Downgrades and steep upgrade sections were found to increase truck-related crashes. The number of rainy days per year was found to be a significant variable affecting truck-related crashes. On the other hand, the presence of climbing lanes has significant safety benefits.

Towards a real-time pneumatic tire performance prediction using an advanced tire-ice interface model

Icy road conditions and tire operational parameters play a vital role in determining the overall performance of a vehicle. This study builds on prior work in the researchers’ group. The Advanced Tire-Ice Interface Model (ATIIM) simulates the temperature rise in the contact patch based on the measured pressure distribution and the thermal properties of the tread compound and of the ice surface. It has the capability to simulate the height of the thin water film created from the melted ice, to predict the tractive performance, and to estimate the viscous friction due to the water layer and the influence of braking operations, including the locked wheel condition. The experimental investigation included measuring the bulk temperature distribution in the contact patch to validate the temperature rise simulations of the ATIIM. As shown by the simulations and the test data, a rise in temperature was observed from the leading edge to the trailing edge of the contact patch. As the wheel load increases, the difference in temperature rise increases, as also reflected in the experimental study. When the temperature difference was significant, a thin water film was observed that resulted in a reduction of friction, which was simulated using the ATIIM.

Protecting the Motor Carrier Against the Threat of Punitive Damages: An Updated Case Review

HISTORICALLY, the case law regarding the issue of damages against trucking companies stemming from the accidents of its drivers has been mostly favorable to trucking companies. This makes sense considering the extremely high standards courts impose before they will award damages. The standard is typically wanton or reckless behavior. (1) Furthermore, a majority of jurisdictions have determined that damages may not be awarded against an employer if the employer is only vicariously responsible for the employee's conduct. (2) For an employer to be liable for damages for conduct arising out of the acts of one of its employees, the employer must have authorized or ratified its employee's wrongful conduct. (3) In most where a truck driver gets into an accident, there is absolutely proof to support a finding that the defendant driver himself acted in such a manner to warrant damages. It is even more difficult for a plaintiff to demonstrate that an employer itself acted with the requisite conduct to warrant damages. Because of this high standard, plaintiffs' attorneys are getting more creative. A quick Google search of punitive damages in trucking cases yields results of many plaintiffs' attorney websites stressing the importance of seeking damages in trucking and offering advice about the means in which the plaintiffs' bar can do so. During our research for this article, we even stumbled across the treatise Litigating Truck Accident Cases, a three volume set that offers substantive guidance to plaintiffs' attorneys to handle personal injury suits involving trucking companies. One of the documents in this volume is a form that provides an outline for a motion in opposition to a motion for summary judgment on the issue of damages. The motion details various examples of specific details that might be used to defeat the trucking company's motion for summary judgment, such as Department of Transportation and Federal Motor Carrier Safety Administration (FMCSA) violations. In the typical trucking case, the plaintiff alleges reckless conduct against the driver, the driver's employer, and any other party the plaintiff can assert a cause of action against. The popular mindset is to allege damages and hope that discovery will offer facts to support the award. If that particular set of facts does not justify such an award, then a defense attorney typically will move to have the damages claim dismissed, and no harm, foul in the eyes of the plaintiffs attorney. With this behavior in mind, it is increasingly important for defense attorneys to move to have the claim for damages dismissed, but it is equally important that the trucking companies themselves stay vigilant. Companies themselves must ensure that, when the plaintiffs attorney begins sifting through the company's discovery responses, there is absolutely nothing there that would prevent the defense attorney from prevailing on a motion for summary judgment to dismiss the damages claim. A personal injury claim against the company typically includes allegations of negligence, such as negligent hiring, negligent training, and negligent supervision. Of course, negligent conduct on the company's part is not enough to support a damages claim. While the specific standard for damages varies based on the jurisdiction, there typically must be an allegation that the company consciously disregarded a known risk. For any of these issues, it is critical to keep in mind that there must be a causal link between the claim in which plaintiff alleges warrants damages and the cause of the accident. In other words, it is arguably irrelevant that the company did not train the drivers on cell phone use if the facts show that the accident occurred when the driver did not have a cell phone with him and the accident was caused by icy road conditions. …

A novel method for modeling skidding for systems with nonholonomic constraints

In this paper, the effect of wheel skidding on the steering motion of a simple vertical rolling disk is investigated. By modifying the nonholonomic constraints, two novel dynamic models are proposed. The first model rotates the constraints and enforces them along a plane correlated to the skid angle. It then relates the skidding in a wheel to the Lagrange multipliers associated with the kinematic constraints of that wheel. The second model relaxes the no-skidding constraint, allowing its transgression and relates the skidding to the generalized velocities of the actuated degrees of freedom of the system. To validate our model, we compare it to one in the literature and we analyze the motion of the disk on icy and snowy road conditions, where skidding can be significant.

Infrared Thermometry in Winter Road Maintenance

Abstract There is significant interest among road authorities in measuring pavement conditions to perform appropriate winter road maintenance. The most common monitoring methods are based on pavement-mounted sensors. This study’s hypothesis is that the temperature distribution in a pavement can be measured by means of a nonintrusive method to retrieve the topmost pavement temperature values. By utilizing the latest infrared (IR) technology, it is possible to retrieve additional information concerning both road temperatures and road conditions. The authors discovered that surface temperature readings from IR sensors are more reliable than data retrieved from traditional surface-mounted sensors during wet, snowy, or icy road conditions. It was also possible to detect changes in the road condition by examining how the temperatures in wheel tracks and in between the wheel tracks differ from a reference dry road condition. The conclusion was that nonintrusive measurement of the road temperature is able to provide an increase in relation to the knowledge about both the road temperature and the road condition. Another conclusion was that the surface temperature should not be considered as being equal to the ground temperatures retrieved from traditional surface-mounted sensors except under conditions of dry, stable roadways.

Information in motion: road vehicles as wireless relay stations for an ad hoc communications network

There is growing interest among automobile engineers and wireless communications researchers in the concept of a Vehicular Ad-hoc NETwork (VANET). Each motor vehicle on the road today provides a natural platform for mobile communications. When equipped with suitable on-board device, the population of vehicles in a busy area becomes a wireless network capable of relaying signals across considerable distances, without the need for a central transmitter. Among the applications so far suggested are the propagation of safety warnings such as icy road conditions, crime prevention, surveillance aimed at public security, together with less urgent passenger services, and even congestion management. To determine whether and how such a system would function, it is necessary to model two distinct kinds of network simultaneously—the road system and the wireless network. The challenge is signi-cant, not least because of the many factors involved. The authors have adapted a cellular automaton (CA) approach, which is used to investigate the relationship between communication, contention/interference and mobility. The results show how mobility a-ects network performance and how the processing gain G can be used to design e-ective coverage areas which maximize the total network throughput. Most important for safety-critical applications, a VANET can break down under congested road traffic conditions because of radio interference among the vehicles.

Conceptual and Scaling Evaluation of Vehicle Traffic Thermal Effects on Snow/Ice-Covered Roads*

The potential thermal effects of traffic on road surface thermal energy balance under frost/snow cover conditions have been largely ignored in meteorological evaluations of road ice deposit conditions. Preliminary exploration of these effects, particularly for heavy traffic scenarios with calm wind conditions and an ambient temperature of 0°C, is provided in this study using a conceptual model. Observational data were used to constrain the model, and parameterizations were employed to estimate the various heat transfer processes involved. The results indicate that, for heavy traffic situations, as well as for stopped traffic at intersections, the traffic thermal flux contribution at the surface is noticeable in a wide range of possible frost/snow-covered road conditions. The sensitivity to variation in traffic density, speed, and the emissivity of vehicle radiative surfaces, among others, is evaluated. Simple quantification of these traffic thermal effects, which might be considered in operational meteorological model forecasting of icy road conditions, is offered.

Anti-lock brake systems: An assessment of training on driver effectiveness

When activated correctly, Anti-Lock Brake Systems (ABS) can provide drivers with the ability to stop a vehicle in shorter distances and allow for more vehicle control under heavy braking than conventional brake systems. This is especially true under wet or icy road conditions. However, it is believed that many drivers are either unaware of the correct method of activation or they revert back to the old method of pumping the brakes when they are faced with a hard braking situation. This paper examines the effectiveness of implementing low-cost training methods for alerting drivers to the correct brake activation technique. A 4-page, color training pamphlet was developed and subjects were given a short period of time to read it over before being asked to drive on an icy test track. Results indicated that those subjects who received the training were able to stop in shorter distances in a straight line braking event and more often used the correct brake activation technique than those subjects who did not receive the training. However, the stopping distance benefits were not realized in the curved and suprise braking events. These results suggest that the transfer of verbal knowledge may have value as a means for solving the apparent problem of improper ABS usage. However, some additional research should be done to validate these results. Since this experiment was conducted directly after the material was read, the possibility exists that without reinforcement, the trained braking techniques might become extinct in a short period of time.

Vehicle lateral control for automated highway systems

This paper addresses the modeling and control of the lateral motion of a highway vehicle. In particular, a steering controller is designed that tracks the center of the present lane on both curved and straight highway sections without knowledge of the radius of curvature of the road. Also, it is shown that a lane change maneuver can be completed on a curved road section using this controller. The controller is designed using an H/sub /spl infin//-based loop shaping design procedure due to McFarlane and Glover. It is shown that this controller achieves the required performance as well as exhibiting excellent robustness. In particular, the controller's robustness due to varying speeds, icy road conditions, and wind gusts are examined.

Fuzzy Logic Traction Controllers and their Effect on Longitudinal Vehicle Platoon Systems

SUMMARY This paper presents two fuzzy logic traction controllers and investigates their effect on longitudinal platoon systems. A fuzzy logic approach is appealing for traction control because of the nonlinearity and time-varying uncertainty involved in traction control systems The fuzzy logic traction controllers we present regulate brake torque to control wheel slip, which is the normalized difference between wheel and vehicle speed. One fuzzy controller estimates the peak slip corresponding to the maximum tire-road adhesion coefficient and regulates wheel slip at the peak slip. The controller is attractive because of its ability to maximize acceleration and deceleration regardless of road condition. However, we find through simulations the controller's performance degrades in the presence of time-varying uncertainties. The other fuzzy logic controller regulates wheel slip at any desired value. Through simulations we find the controller robust against changing road conditions and uncertainties. The target slip is predetermined and not necessarily the peak slip for all road conditions. If the target slip is set low, stable acceleration and deceleration is guaranteed, regardless of road condition We also study the effect of traction control on longitudinal vehicle platoon systems using simulations. The simulations include acceleration and deceleration maneuvers on an icy road. The results indicate traction control may substantially improve longitudinal platoon performance, especially when icy road conditions exist.

The effect of roadway salting on safety and mobility

The research detailed in this report represents a preliminary effort to develop an understanding of the effects of roadway salting on road safety and mobility.Analyses included an assessment of available literature, the review of accident data from a number of sources, and the development of a study procedure for assessing the effects of winter conditions and maintenance activities on vehicle operations. The procedure developed was based on vehicle headway observations.Field trials of the study procedure in six different jurisdictions confirmed it to be sensitive to roadway conditions, and to be capable of reflecting the effects of maintenance activities. Results of the studies showed little variation for mean headways under dry, wet, and slushy road conditions. Mean headways under show or icy road conditions were much larger. Limited study of the effects of maintenance activities suggested that different roadway salting strategies had little differential effect on vehicle headways. Finally a variety of study refinements were identified.Analyses of accident data was not conclusive with data from the 11 jurisdictions reviewed showing remarkable consistency in the proportion of accidents experienced under winter versus nonwinter conditions. This consistency was unexpected in view of the variations in weather conditions, maintenance strategies, and metropolitan characteristics of the study group. Key words: salt, snow, ice, sodium chloride, level of service, winter maintenance, deicers, and snow and ice control.

THE INCREASE OF CORNERING FORCE AND TRACTION BY A WHEEL-SLIP-CONTROL-SYSTEM

SUMMARY The present paper investigates some questions of safety in traffic especially vehicle dynamics under changing slippery and icy road conditions. Whereas the well introduced “Antilock-System” (ABS) is concerned with deceleration, an engine directed “Wheel-Slip-Control-System” (ASR) will increase the comfort and safety potential when accelerating. Measured and calculated results of such a system are compared to those of noncontrolled vehicles with different driveline concepts. As far as the here discussed cornering manoeuvres are concerned the active safety is comparable to that of a four wheel driven car.

Driver Reaction to a Technical Safety Measure—Studded Tires

An investigation was conducted to determine if drivers of vehicles with studded tires are making use of the increased coefficient of friction on icy roads to maintain a higher speed or to drive at a higher level of safety than do drivers with unstudded tires. Speeds, following-distances, and presence of studded tires were checked on several thousand vehicles in real traffic during early morning hours. The sample studied consisted of drivers in traffic between a suburb and the town of Uppsala. The measurements were carried out with traffic analyzers and studded-tires indicators on two consecutive curves. Studies were made in both dry and icy road conditions. The safety level was calculated in the following ways: (1) the quotient between coefficient of friction used and the maximum friction available in the curve, and (2) the quotient between actual speed and the highest possible speed in the curve. The results showed that, although drivers with vehicles equipped with studded tires are driving somewhat faster than drivers with unstudded tires in icy (low friction) road conditions, this increase in speed does not lead to lower safety. On the contrary, drivers with studded tires are, on the average, driving with larger safety margins than drivers with unstudded tires. In dry (high friction) road conditions, no clear differences in safety or speed were found.