Measuring Driver Performance in Braking Maneuvers

1996 ◽  
Vol 1550 (1) ◽  
pp. 8-15 ◽  
Author(s):  
Rodger J. Koppa ◽  
Daniel B. Fambro ◽  
Richard A. Zimmer
Keyword(s):  
Response Time ◽  
Empirical Investigation ◽  
Test Vehicle ◽  
Research Project ◽  
Braking Performance ◽  
The Road ◽  
Sight Distance ◽  
Driver Performance ◽  
On The Road ◽  
Stopping Sight Distance

A simple, reliable instrumentation package with an on-board computer for installation in a test vehicle or the test driver's own vehicle is described. This package was used in a research project recently completed, an empirical investigation of stopping sight distance. Selected data on perception-response time (PRT) and braking performance under artificial and simulated on-the-road emergency conditions are presented. PRTs were less than the AASHTO assumed constant of 2.5 sec even at the 95th percentile. Braking performance in terms of steady deceleration was greater than −0.32 g at the 95th percentile.

Driver Perception–Brake Response in Stopping Sight Distance Situations

1998 ◽  
Vol 1628 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Daniel B. Fambro ◽  
Rodger J. Koppa ◽  
Dale L. Picha ◽  
Kay Fitzpatrick
Keyword(s):  
Response Time ◽  
Performance Studies ◽  
Response Times ◽  
Highway Design ◽  
Braking Performance ◽  
Reaction Distance ◽  
State Highway ◽  
Sight Distance ◽  
Design Speed ◽  
Stopping Sight Distance

One of the most important requirements in highway design is the provision of adequate stopping sight distance at every point along the roadway. At a minimum, this sight distance should be long enough to enable a vehicle traveling at or near the design speed to stop before reaching a stationary object in its path. Stopping sight distance is the sum of two components–brake reaction distance and braking distance. Brake reaction distance is based on the vehicle’s speed and the driver’s perception–brake reaction time (PBRT). Four separate, but coordinated, driver braking performance studies measured driver perception–brake response to several different stopping sight distance situations. The results from the driver braking performance studies suggest that the mean perception–brake response time to an unexpected object scenario under controlled and open road conditions is about 1.1 s. The 95th percentile perception–brake response times for these same conditions was 2.0 s. The findings from these studies are consistent with those in the literature: that is, most drivers are capable of responding to an unexpected hazard in the roadway in 2.0 s or less. Thus, the American Association of State Highway and Transportation Officials’ perception–brake response time of 2.5 s encompasses most of the driving population and is an appropriate value for highway design.

Motorcyclist perception response time in stopping sight distance situations

2012 ◽  
Vol 50 (3) ◽  
pp. 371-377 ◽  
Author(s):  
Seyed Rasoul Davoodi ◽  
Hussain Hamid ◽  
Mahdieh Pazhouhanfar ◽  
Jeffrey W. Muttart
Keyword(s):  
Response Time ◽  
Sight Distance ◽  
Stopping Sight Distance

Driver Braking Performance in Stopping Sight Distance Situations

2000 ◽  
Vol 1701 (1) ◽  
pp. 9-16 ◽  
Author(s):  
Daniel B. Fambro ◽  
Rodger J. Koppa ◽  
Dale L. Picha ◽  
Kay Fitzpatrick
Keyword(s):  
Emergency Situation ◽  
Practical Significance ◽  
Braking Performance ◽  
Additional Information ◽  
Emergency Situations ◽  
Sight Distance ◽  
Directional Control ◽  
Average Maximum ◽  
Stopping Sight Distance ◽  
Maximum Deceleration

Assumed driver braking performance in emergency situations is not consistent in the published literature. A 1955 study stated that in an emergency situation “it is suspected that drivers apply their brakes as hard as possible.” This idea differs from a 1984 report that states drivers will “modulate”their braking to maintain directional control. Thus, additional information is needed about driver braking performance when an unexpected object is in the roadway. In this research driver braking distances and decelerations to both unexpected and anticipated stops were measured. The study design allowed for differences in vehicle handling and driver capabilities associated with antilock braking systems (ABS), wet and dry pavement conditions, and the effects of roadway geometry. Vehicle speeds, braking distances, and deceleration profiles were determined for each braking maneuver. The research results show that ABS result in shorter braking distances by as much as 30 m at 90 km/h. These differences were most noticeable on wet pavements where ABS resulted in better control and shorter braking distances. Braking distances on horizontal curves were slightly longer than on tangent sections; however, they were not large enough to be of practical significance. Maximum deceleration during braking is independent of initial velocity, at least in the range of speeds tested. Differences were noted in individual driver performance in terms of maximum deceleration. Although maximum deceleration was equal to the pavement’s coefficient of friction for some drivers, the average maximum deceleration was about 75 percent of that level. Overall, drivers generated maximum decelerations from 6.9 to 9.1 m/s2. The equivalent constant deceleration also varied among drivers. Based on the 90-km/h data, 90 percent of all drivers without ABS chose equivalent constant decelerations of at least 3.4 m/s2 under wet conditions, and 90 percent of all drivers with ABS chose equivalent constant deceleration of at least 4.7 m/s2 on dry pavements.

The Effect of Changes in some Vehicle Handling Variables on Driver Steering Performance

1966 ◽  
Vol 8 (3) ◽  
pp. 245-263 ◽  
Author(s):  
Errol R. Hoffmann ◽  
Peter N. Joubert
Keyword(s):  
Response Time ◽  
Indirect Measurement ◽  
Gear Ratio ◽  
Mental Capacity ◽  
Testing Time ◽  
Vehicle Handling ◽  
Sight Distance ◽  
Driver Performance ◽  
Vehicle Response ◽  
Steering Torque

The literature on vehicle handling is summarized. Experiments were carried out to determine the effect of vehicle response time, steering gear ratio, and near- and far-sight distances on driver performance on a tracking task consisting of driving through a narrow winding course marked by traffic cones. The vehicle response time was found to affect greatly the number of cones touched by the vehicle during a set testing time. On the particular track used in these tests, the driver performed best when the vehicle response time was 0.20 seconds. The near and far distances over which the driver could see the test course were also found to be of importance. Increasing near-sight distance, with no limit on the far-sight distance produced poorer driver performance. This also occurred for the case of decreasing far-sight distance with fixed near-sight distance. Tests with variations of steering ratio and steering torque produced little change in driver performance, although there was a weak minimum in cone scores at a steering ratio G = 24. In some of the experiments reported here, spare mental capacity was measured during the test period. For this indirect measurement of task difficulty, changes in the spare mental capacity of the driver were found to have the same sensitivity to changes in the vehicle, as did the change in the number of cones touched by the vehicle.

Current and Future Research Activities in Driver Training

1977 ◽  
Vol 21 (6) ◽  
pp. 482-484
Author(s):  
Robert M. Nicholson ◽  
Michael F. Smith
Keyword(s):  
Future Research ◽  
Safety Education ◽  
Driver Education ◽  
Driver Training ◽  
The Road ◽  
Elderly Driver ◽  
Research Activities ◽  
Driver Performance ◽  
Pros And Cons ◽  
On The Road

Research programs involving high school driver education, motorcyclist safety education, problem driver retraining, elderly driver retraining, handicapped driver training, commercial vehicle driver training, and an energy efficient driver training program are summarized. Some of the pros and cons of driver education are presented and problems with establishing valid on-the-road driver performance tests are discussed.

Evaluation Method about Braking Force Utilization

2013 ◽  
Vol 631-632 ◽  
pp. 910-914
Author(s):  
Yan Zhang ◽  
Cheng Ye Liu
Keyword(s):  
Evaluation Method ◽  
Force Distribution ◽  
Braking Performance ◽  
Adhesion Coefficient ◽  
The Road ◽  
High Adhesion ◽  
Braking Force ◽  
On The Road

For the braking performance investigated when vehicle was on the road of different road adhesion coefficient, the match of ideal braking force distribution curves of front and rear wheels and front and rear arresters was studied. The concept of braking performance to reflect "braking force utilization" was introduced.The braking force utilization algorithm came out depending on the different matches. A light bus was chosen as an example. Vehicle braking performance under different road adhesion coefficient was studied in detail.At the same time, vehicle braking performance under different matches was studied with braking force distribution value changed. The results indicate that, braking force utilization appears first increased and then decreased with the increase of road adhesion coefficient.Along with the increase of braking force distribution value,the braking force utilization decreased on low adhesion coefficient road,then increased on high adhesion coefficient road.The method could evaluate the braking performance on the road of different road adhesion coefficient efficiently.

Mathematical Models of Vehicular Speed on Mountain Roads

2000 ◽  
Vol 1701 (1) ◽  
pp. 104-110 ◽  
Author(s):  
Pedro Jose Andueza
Keyword(s):  
Mathematical Models ◽  
Design Procedure ◽  
Average Speed ◽  
The Road ◽  
Geometric Conditions ◽  
Sight Distance ◽  
Efficiency Measures ◽  
Vehicular Speed ◽  
On The Road ◽  
Design Speed

Mathematical models were developed to estimate vehicular speed on curves and tangents in mountain roads. The 85th percentile speed for curves was estimated by using the radius of the curve under consideration, the radius of the previous curve, sight distance in the curve, and tangent length before the curve. The average speed was calculated by using the radius of the curve under consideration, the radius of the previous curve, and sight distance. The 85th percentile and the average speed were estimated by using the radius of the previous curve and tangent length. Speeds adopted by drivers respond not to engineer’s design speed but to geometric characteristics of the road. A design procedure is proposed that takes advantage of available design speed and driver behavior on the road at the same time. On a curve, drivers consider two efficiency measures: speed and comfort. On some curves, they prefer to feel a certain degree of discomfort in exchange for obtaining greater speeds. For some geometric conditions, drivers adopt a speed that sacrifices not only comfort but also safety.

Reliability indices for road geometric design

1992 ◽  
Vol 19 (5) ◽  
pp. 760-766 ◽  
Author(s):  
Francis P. D. Navin
Keyword(s):  
Reliability Index ◽  
Design Parameters ◽  
Limit States ◽  
Highway Design ◽  
Reliability Indices ◽  
The Road ◽  
Modifying Factors ◽  
Sight Distance ◽  
Margin Of Safety ◽  
Stopping Sight Distance

Highway engineers, when asked to state the safety of a particular design, are usually at a loss to give a single meaningful measure as is possible in structural or geotechnical engineering. This paper outlines a method to estimate the margin of safety and reliability index for isolated highway components. The stopping sight distance is used to demonstrate the method. The method uses the basic highway design equations. On the assumption that the variables are random, the expected value of the mean and the variance are estimated; and from these the margin of safety and the reliability index are calculated. The most likely combination of variables for the existing design condition may also be estimated. The variables included represent the characteristics of the driver, the vehicle, and the road surface.A method is proposed to specify the design parameter's value representing a road's strategic importance, the users, the vehicles, the drivers, the environment, the terrain, and the standard of design and construction. The apparent advantage of the proposed reliability-based method is that the designer must explicitly specify the importance of the modifying factors and may also more closely investigate the behaviour of the variables in the design parameters in the critical region near noncompliance. Key words: limit states design, stopping sight distance, safety, highway design, reliability.

scholarly journals Evaluating the Impact of Sight Distance and Geometric Alignment on Driver Performance in Freeway Exits Diverging Area Based on Simulated Driving Data

2021 ◽  
Vol 13 (11) ◽  
pp. 6368
Author(s):  
Xizhen Zhou ◽  
Binghong Pan ◽  
Yang Shao
Keyword(s):  
Traffic Safety ◽  
Shaanxi Province ◽  
Driving Safety ◽  
Steering Wheel ◽  
Sight Distance ◽  
Driver Performance ◽  
Stopping Sight Distance ◽  
The Right ◽  
The Impact ◽  
Circular Curve

The decision sight distance (DSD) at freeway exits is a major factor affecting traffic safety. Based on the Hechizhai Interchange in Xi’an City (Shaanxi Province, China), this paper designs a simulation experiment. Through a simulator study and a questionnaire survey, this paper discusses the impact of the DSD, 1.25 times the stopping sight distance (SSD) and a circular curve deflection on a driver’s driving state (including steering wheel angle rate and steering wheel angle frequency domain). Thirty volunteers participated in this research. The result shows that (1) it is safer to drive on an exit that meets DSD. (2) If it only meets the 1.25 times the SSD requirement, the overloaded driving tasks and operation would be more likely to cause crashes. The driving state of the driver on the right circular curve is obviously better than that on the left circular curve, because changing lanes to the right on the left circular curve does not meet the driver’s expectations. (3) Left and right circular curve should be treated differently in the driving area and the constant sight distance requirements should not be applied. (4) The left circular curve should be more stringent to ensure driving safety.

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