Driver Perception-reaction Time Research Articles

Transportation-Related Human Factors in High-Altitude Regions: Review, Needs, and Novelties

The low pressure at high altitudes (above 2500 m) causes hypoxia (decreased oxygen) that affects people’s physiological and psychological characteristics. Specifically, hypoxia may affect the neural function of the brain, leading to severe cognitive deficits and a significant decline in memory function and attention. This article addresses the effect of human factors on transportation design and operation at high altitudes (HA), with some details on the Tibet-China region. Specifically, the paper first reviews the basic transportation-related concepts for high altitude, including oxygen and temperature levels, driver perception-reaction time, hazard perception, vehicle speed, and walking speed. Then, the transportation users affected by high altitudes are discussed, including drivers, pedestrians, cyclists, passengers, and others. Next, the impacts of human factors on highway design and operation for HA regions are discussed along with the research needs. Finally, recent innovations to address the challenges of HA transportation are presented, along with case studies comparing some human factors of the plateau and plain areas. This article represents a valuable reference for future research in HA regions to improve transportation design and safety

Visual Performance and Motorcycle Safety-Related Impacts of Various High Beam Headlight Intensities


 
 
 In Malaysia, the three main types of motorcycle accidents include collision with passenger cars, collision with other motorcycles and single-motorcycle accidents. An accident may occur due to the lack of road design consistency and visibility where most drivers make more errors in the absence of geometric features. One of the most important barriers to the more frequent use of high beam headlight is the length of visibility of the headlight beam in relation to the stopping distance of a vehicle. Furthermore, it is crucial to evaluate the current limits on the luminous intensity of high beam headlights that is considered visible for a driver to come to a stop. Therefore, this first stage study summarizes and investigates the stopping sight distances, braking distances that allow for the evaluation of the vehicle's performance to increase the capability of both the driver and vehicle with regard to safety. A total of ten experiments were carried out with a passenger car, the Perodua Myvi, on a road within a local university. The results found that Stopping Sight Distance (SSD) could be used to determine the SSD graph by considering the velocity (v0), driver's perception reaction time (tR), coefficient of breaking friction (fT), gravitational constant (g), deceleration rate (a) and roadway grade (G). The study also concludes that SSD could be used to determine the SSD graph by considering the velocity (v0), driver’s perception reaction time (tR), coefficient of breaking friction (fT), gravitational constant (g), deceleration rate (a) and roadway grade (G). Ultimately, the study also indicates that the time to switch to hi-beam (Automatic High Beam – AHB) is at SSD distance (meter or second).
 
 

Characterizing driver behavior in dilemma zones at signalized roundabouts

In some Asian countries, roundabouts were designed as a tool for landscape and urban planning in less-populated areas, which did not initially need traffic lights. However, as the urbanization grew, it was needed to signalize these roundabouts to prevent accidents. One of the main reasons for high accident rates at intersections is the dilemma that drivers face when the signal changes from green to yellow. The purpose of this paper is to study the dilemma zone (DZ) at roundabouts and driving factors that affect the stop or go decision. This paper determines the length of all-red interval for yellow light running (YLR) vehicles, using time to collision (TTC) and kinematic motion (KM) methods. TTC sets all-red interval so that the “last to go” vehicles have enough time to clear middle of the roundabout before conflicting vehicles reach the conflict point. KM method applies the kinematic motion equations to estimate the time required to clear the conflict point. The obtained results for three roundabouts in Mashhad, Iran demonstrate that the DZ is shorter and closer to stop-line, as compared to signalized intersections. Drivers drive more conservatively at roundabouts and are more willing to stop. Comparison of TTC and KM reveals that the central tendency and dispersion measures of all-red interval are larger in disaggregate KM method. Studying driving factors shows that driver perception-reaction time of drivers at roundabouts matches to a large extent with the values recommended by AASHTO and ITE. However, such consistency is not observed for acceleration and deceleration rates.

A Study on Driver Perception-Reaction Time in High-Speed Driving Situations

A Study on Driver Perception-Reaction Time in High-Speed Driving Situations

Upon an issue of correlation between the running speed of vehicles and traffic capacity of a road section

The paper focuses on current algorithms for calculating the traffic capacity of the road sections, provided in various national standards. These algorithms were jointly considering some common groups of factors, such as factors related to the dynamic performance of vehicles and factors related to geometrical - dimensional configuration of the road. The algorithms have particular forms for continuous traffic flow and for discontinuous traffic. As a first stage, there were considered the algorithms for the continuous flows, for which were studied the points of extreme variance for traffic capacity, depending on the running speed. Maximum traffic capacity analytical form for a road section, in continuous traffic flow variant does not depend explicitly of average speed, but allows the evaluation of certain important factors (length section, acceleration at start-up, braking deceleration of vehicles, driver's perception-reaction time, brake friction coefficient, etc.). Consequently, various ways are identified to improve road traffic capacity. The paper justifies reconsideration of the notion of traffic fluence as defined by various national standards; as it stands, the definition of fluency is artificial in relation to the maximum legal speed on that road section, even though the value of that speed is physically impossible.

How Does the Driver's Perception Reaction Time Affect the Performances of Crash Surrogate Measures?

With the merit on representing traffic conflict through examining the crash mechanism and causality proactively, crash surrogate measures have long been proposed and applied to evaluate the traffic safety. However, the driver’s Perception-Reaction Time (PRT), an important variable in crash mechanism, has not been considered widely into surrogate measures. In this regard, it is important to know how the PRT affects the performances of surrogate indicators. To this end, three widely used surrogate measures are firstly modified by involving the PRT into their crash mechanisms. Then, in order to examine the difference caused by the PRT, a comparative study is carried out on a freeway section of the Pacific Motorway, Australia. This result suggests that the surrogate indicators’ performances in representing rear-end crash risks are improved with the incorporating of the PRT for the investigated section.

Study of Truck Driver Behavior for Design of Traffic Signal Yellow and Clearance Timings

Traffic signal violations by drivers are a leading contributor to crashes at signalized intersections. The yellow indication is used to inform drivers of an upcoming change in the status of the traffic signal. Yellow interval durations are currently calculated to provide dilemma zone protection for passenger cars. Because of differences in vehicle characteristics and driver characteristics, heavy trucks such as tractor trailers behave differently at the onset of a yellow indication. This paper characterizes the difference in driver behavior between truck and light-duty vehicles at the onset of the yellow indication and then revises the yellow timing procedures to address the truck requirements. A data set of 910 stop–go records was collected through the use of a truck driving simulator located at the Virginia Tech Transportation Institute. From the data collected, statistical models were created to model driver perception–reaction times and deceleration levels with a consideration of driver attributes and the time to the intersection at the onset of the yellow indication. The data collected, along with the statistical models developed, were compared with the data collected and the statistical models created by the same research organization in a study of passenger car drivers. Last, a Monte Carlo simulation was conducted to develop appropriate yellow indication timings to provide adequate dilemma zone protection for trucks.

Design of Traffic Signal Clearance Intervals to Consider Impacts of Buses

Traffic signal design procedures use only light-duty vehicles in the design of yellow and clearance intervals. For quantification of the impact of buses on yellow and clearance times, a controlled field experiment was conducted. In the study, 864 stop and run records were collected for a 56 km/h (35 mph) approach speed; participant bus drivers encountered a yellow indication initiation at different distances from the intersection. Participant drivers were selected randomly from three age groups (i.e., younger than 40 years old, 40 to 64 years old, and 65 years or older), and an equal number of male and female participants was included in each age group. Data collected were used to generate two linear mixed models: one for bus driver perception–reaction times and one for deceleration levels. Both models considered roadway surface and environmental parameters, driver attributes (i.e., age and gender), roadway grade, approaching speed, and time and distance to the intersection at the onset of yellow. The proposed models were used to perform a Monte Carlo simulation to generate yellow timing and all-red durations. Lookup tables were generated for the proposed yellow timing duration for different approach speeds, roadway grades, confidence intervals, precipitation, and percentage of buses in the traffic stream to provide practical guidelines for the design of traffic signal clearance times.

Assessing how Drivers of through Vehicles React to Driveway Activity

As population and development levels increase in both urban and rural areas, the implementation of access management strategies is vital for creating safe, efficient, and sustainable transportation systems. To meet the changing needs of transportation systems and their users, the accuracy and the applicability of the base assumptions used to develop access management guidelines must be verified. This research effort utilized a driving simulator study to investigate several assumptions related to driver behavior and access management. The simulator study focused on driver perception–reaction time in the vicinity of driveways and driver behavior in response to differing driveway activity types. The results indicated that the average and 85th percentile perception–reaction times for all drivers were 2.8 s and 4.3 s, respectively. Surprisingly, older drivers (age 65 and older) appeared to be more alert and had an 85th percentile perception–reaction time a full second shorter than that of their younger counterparts (3.3 s versus 4.4 s). The researchers also observed that deceleration rates had a curvilinear (not constant) relationship with vehicle speed, and these values were much lower than the accepted AASHTO value of 11.2 ft/s2. Finally, the predominant response to driveway activity was a slowing maneuver, not a stop or a lane change. This finding suggests that sight distance calculations based on an urgent stop may not be the most appropriate metric for determining access spacing guidelines for commercial urban road environments.

Designing Traffic Signal Yellow and Change Intervals considering Truck Impacts

This research quantifies the effect of heavy vehicles on the design of yellow and all-red intervals. With empirical data from previous studies and truck performance characteristics, models are developed to simulate driver perception–reaction times and truck deceleration levels at signalized intersections. These models consider roadway surface and weather conditions (dry, fog, or rain); driver attributes (age and gender); roadway grade; approach speed; and time and distance to the intersection at the onset of the yellow indication. An agent-based approach is used to develop driver- and vehicle-specific yellow times. The yellow timings for light-duty and heavy-duty vehicles are then combined and consider different percentages of heavy vehicles in the traffic stream. Lookup tables are developed for grades, precipitation types and levels, and percentages of trucks to provide practical guidelines for the design of yellow and all-red signal timings. In general, the research demonstrates that adding trucks to the traffic stream increases yellow times by 2% to 20%, depending on approach speed, grade, and weather conditions, with the most significant increases occurring on dry roadways with high positive gradients at lower speeds. In absolute terms, the yellow time is increased from approximately 0.1 to 0.6 s when trucks constitute 5% of the traffic stream to 0.6 to 1.4 s when trucks are 30% of the traffic stream. The study also demonstrates a need to increase the all-red time by up to 0.5 s when trucks comprise 30% of the traffic stream.

Evaluation of Driver Perception–Reaction Time under Rainy or Wet Roadway Conditions at Onset of Yellow Indication

The research presented in this paper characterizes the impact of a wet pavement surface and rainy weather conditions on driver perception–reaction time (PRT) at the onset of the yellow indication on the approach to a high-speed signalized intersection. An in-vehicle differential Global Positioning System was used in a controlled field environment. Three hundred eighty-four data records for all drivers who stopped at the onset of the yellow indication were available for analysis. The minimum time to intersection (TTI) ranged from 2.35 s to 5.71 s. Statistical analyses were used to quantify the effects of the TTI, grade (uphill or downhill), gender, and age (<40 years, 40 to 59 years, and ≥60 years) on driver PRT. The study demonstrated that driver PRT increases as TTI increases. A longer PRT was found when vehicles traveled along an upgrade section, given that the driver was typically accelerating when the yellow indication was initiated. No gender differences were found in PRT, and no statistically significant differences were found between different age groups. Furthermore, the study demonstrated that driver PRT increased under conditions of a wet pavement surface and rainy weather as compared with clear weather conditions over the entire TTI range.

Designing Yellow Intervals for Rainy and Wet Roadway Conditions

The research presented in this paper quantifies and models the impact of wet pavement surface and rainy weather conditions on driver perception-reaction times (PRTs), deceleration levels, and traffic signal change interval durations. A total of 648 stop-run records were collected as part of the research effort for a 72 km/h (45 mi/h) approach speed where participant drivers encountered a yellow indication initiation at different distances from the intersection. The participant drivers were randomly selected in different age groups (under 40 years old, 40 to 59 years old, and 60 years of age or older) and genders (female and male). Using the gathered data, statistical models for driver PRT and deceleration levels were developed, considering roadway surface and environmental parameters, driver attributes (age and gender), roadway grade, approaching speed, and time and distance to the intersection at the onset of yellow. Inclement weather yellow timings were then developed and summarized in lookup tables as a function of different factors (driver age/gender, roadway grade, speed limit, precipitation level, and roadway surface condition) to provide practical guidelines for the design of yellow signal timings in wet and rainy weather conditions. The results indicate that wet roadway surface conditions require a 5 percent increase in the change interval and that rainy conditions require a 10 percent or more increase in the duration of the change interval. These recommended change durations can also be integrated within the Vehicle Infrastructure Integration (VII) initiative to provide customizable driver warnings prior to a transition to a red indication.

Novel Stochastic Procedure for Designing Yellow Intervals at Signalized Intersections

Driver behavior while approaching high-speed signalized intersections at the onset of a yellow indication varies as a function of many parameters including age, gender, perception-reaction time, and acceptable deceleration levels. This paper develops a novel approach for computing the clearance interval duration that explicitly accounts for the reliability of the design (probability that drivers do not encounter a dilemma zone). Lookup tables are developed to assist practitioners in the design of yellow timings. The approach is demonstrated using data gathered along the Smart Road test facility for dry and clear weather conditions for two approach speeds: 72.4 km/h and 88.5 km/h. Each data set includes a complete tracking of the vehicle every decisecond within 150 m before and after the intersection. A total of 2016 signal stopping records were gathered. Using these data, models that characterize driver perception-reaction times and deceleration levels are developed. Based on these models, lookup table are developed to assist practitioners in the design of yellow timings that reflects the stochastic nature of driver perception-reaction time (PRT) and deceleration levels.

Empirical Study of Impact of Icy Roadway Surface Condition on Driver Car-Following Behavior

Research was done to quantify the impact of icy roadway conditions on driver car-following behavior. The data used in the study were gathered by a group of researchers at Japan's Hokkaido University in a controlled environment under dry and icy roadway conditions. The data were used to calibrate the Van Aerde steady-state car-following model, along with vehicle acceleration and deceleration constraints. The impact of icy roadway conditions on five driver-specific car-following parameters [driver perception–reaction time (PRT), free-flow or desired speed, speed-at-capacity, capacity, and jam density] was conducted with one-way analysis of variance and Kruskal–Wallis tests. The results demonstrate that icy roadway conditions produce statistically significant differences at a 5% significance level. Specifically, icy roadway conditions reduce the mean free-flow speed, speed at capacity, and capacity by 28%, 13%, and 46%, respectively, compared with driving on dry roadways. The mean PRT for icy conditions is found to take 13% longer than driving under dry conditions. The longer PRTs can be attributed to drivers driving at lower speeds and larger spacing on icy surfaces compared with dry conditions.

Estimating total manoeuvring time of drivers using Gamma distribution function of instantaneous speeds

The Total Manoeuvring Time (TMT) of commuting drivers was analyzed by gamma density functions of vehic-le instantaneous speeds and transforming the functions to log normal distributions to determine the cumulative response times. The instantaneous speeds of 50 passenger vehicles were read from the speedometers at non-peak traffic periods on 4 segments of an urban arterial in Ilorin (Nigeria) in 2006. The ages of drivers, service period of vehicles, and pavement conditions were also obtained by interviewing the drivers. A model of cumul-ative response times of driver-vehicle-road interaction developed indicated that TMT was contributed by the interactions of driver perception-reaction time, steering time and vehicle response time in the proportion of 67 %, 22 % and 10 % respectively.

Modeling Driver Behavior within a Signalized Intersection Approach Decision–Dilemma Zone

This study uses data gathered in a field test on 60 test participants to develop models that characterize driver brake perception–reaction times (PRTs), brake times, and stop–go decisions at the onset of a yellow indication at a high-speed signalized intersection approach. The study demonstrates that driver PRTs are influenced only by the driver's time to intersection (TTI) at the onset of the yellow indication. The driver PRT is found to increase linearly with TTI and is not affected by the vehicle speed (in the range of 54 to 88 km/h), driver gender, or driver age. In the case of stop–go behavior, the older driver (≥65 years of age) dilemma zone is wider, ranging from a TTI of 4.81 to 1.66 s versus 4.90 to 2.87 s for the younger age group. Female drivers are more likely to stop than male drivers and tend to have a dilemma zone that is closer to the intersection. Finally, the study demonstrates that dilemma zone control systems should consider a dilemma zone from 5.0 to 1.5 s instead of the current state of practice of 5.5 to 2.5 s to capture all potential driver age and gender groups.

Effects of Interface Workload of In-Vehicle Information Systems on Driving Safety

Driver distraction and lack of awareness of the driving situation are major causes of accidents in the urban areas in Taiwan; failing to obey traffic signals is the third leading accident cause. Numerous innovative in-vehicle information systems (IVIS) could be used collectively to provide drivers with a variety of information, such as messages from intersection collision warning systems (ICWS) by way of different in-vehicle interfaces. How the different IVIS interfaces influence driver workload and safety is always an important issue. This study investigates the effects of auditory ICWS messages on driver performance while the driver's visual, hearing, or mental processing attention resources (or all three) are engaged by secondary tasks. This type of engagement or distraction commonly occurs when a driver uses IVIS. The secondary tasks used to distract drivers were created by different types of mathematical questions presented with different types of display devices (e.g., voice from a speaker or numbers shown on a liquid crystal display screen or head-up display). Mixed linear models were employed to examine the factors influencing driver perception–reaction time with the consideration of repeated measures. Several factors, including several main factors and an interaction, were found to be significant. The most important finding was that the interaction between provision of ICWS information and the display format indicated that an auditory warning message could increase driver perception–reaction time while a driver was distracted by an auditory task. In addition, it was found that driver distraction due to different mental processing tasks had a significant impact on driver perception–reaction time.

Crash Reduction with an Advance Brake Warning System: A Digital Simulation

A digital Monte Carlo-type simulation was used to evaluate the effectiveness of an advance brake warning system (ABWS) in reducing rear-end collisions. The ABWS we evaluated activates the brake lights in response to rapid release of the gas pedal, which is characteristic of emergency braking. This reduces the lag in the onset of the brake light by the movement time from the gas pedal to the brake pedal. Using empirical distributions of driver perception reaction time and movement times, it was shown that the ABWS is most effective in preventing collisions on dry roads whenever the headway between vehicles decreases to 1.0 s or less. Vehicle speed was not a significant factor in crash prevention or severity reduction.

Giving the older driver enough perception-reaction time.

Many types of behavior slow with age, and older drivers require more time to process information and make decisions. How greater response time requirements relate to the design of the highway environment and to features of new in-vehicle technologies is discussed. The design requirements for many different aspects of roadway geometrics and traffic control devices are based on design driver perception-reaction times. However, without knowing how much slower older drivers are than the design driver, it is difficult to determine whether they are adequately protected by current design practice and, if not, what the desired change in design should be. Attempts to address this have been hampered by the lack of directly relevant data, the situation-specific nature of certain findings, and the older driver's ability to compensate for declines in basic skills. Also discussed are the promise and problems of new in-vehicle technologies for providing the older driver with adequate time to act. These intelligent vehicle highway systems (IVHS) may speed navigational decision making and recognition of hazards and maneuver requirements. However, the possibility for interfering with quick responding also arises, and IVHS systems might disadvantage the older driver in other ways.

Designing and Operating Safer Highways for Older Drivers: Present and Future Research Issues

A major shift is occurring in the population age distribution resulting in a growing number of older persons with an increasing demand for mobility. For a variety of reasons, meeting the present and future mobility needs of older persons will depend primarilary on the automobile. This paper will discuss key issues related to ongoing and planned research sponsored by the Federal Highway Administration (FHWA) to improve the mobility and safety of older drivers and pedestrians. The scope of FHWA research activities concerns aspects of highway design and operations that involve direct user interface. For example, geometric design and traffic control device standards explicitly consider quantifiable driver characteristics such as perception-reaction time or visual acuity. Ongoing research is addressing the extent to which existing traffic control device elements accommodate drivers with age-related diminished performance capabilities. Current work is testing older driver responses to brighter and larger signs with varying legend spacing and font characteristics in order to make recommended changes to existing highway signing standards. Older driver perception-reaction time is being evaluated in a variety of intersection, stopping, and decision sight distance situations. Studies are also underway to improve pavement markings and delineation systems to enhance their utility for older drivers. Driving simulation and field methods are being used to investigate vehicle maneuvers which cause difficulties for older drivers so that improvements can be made to highway design and operations. Future studies will determine the capabilities and limitations of older pedestrians, address the visibility problems of symbol signs and changeable message signs, and investigate all aspects of intersection design and operations in light of older driver and pedestrian capabilities.