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Sleep deprivation and sleep disorder continues to cause problems on the road. Reducing the number of accidents related to driver fatigue would save the society a significant amount of money and personal suffering. Monitoring the driver's symptoms can help determine driver fatigue early enough to prevent accidents due to lack of awareness. This report describes advances towards a non-intrusive approach for real-time detection of driver fatigue. It uses a video camera that points directly toward the driver's face and monitors the driver's eye to detect micro-sleeps, or short periods of sleep of about three-to-four seconds.

This report presents data using multiple-choice questionnaires to learn how drivers respond to traffic information in the form of advisory messages. Two experiments, comprising 112 participants, were conducted using the same technique and yielding similar results. The traffic information messages presented to participants varied in three respects; quantitativeness of information, imperativeness of advice, and timeliness of information. Two additional factors were examined; the amount of traffic congestion stated to be directly observable on the route and the stated accuracy of messages received in the past. Results obtained from the questionnaires indicate that the structure of the traffic message did influence the driver behavior. The propensity to depart from the planned route ahead of schedule was greater when respondents had; few exit options remaining, been told traffic levels were high, received accurate traffic information in the past, and had received messages which contained quantitative and/or imperative information. Traffic controllers with this knowledge of driver behavior could act to further reduce trip times and congestion by using the control tools currently available to them. The major conclusion we can draw from this study is that when possible and appropriate, advisory messages should contain accurate, timely, quantitative and imperative information.

This work reports results of an experimental program on human factors issues in traffic signing. The first task examines the problems associated with the programming of signs for evaluation of driver response in simulation. It is concluded that growing technical tools permit traffic engineers to test proposed signage, and avenues of implementation are given. The second task examines driver response in simulation to multiple real-world signs. It is concluded that while much effort is given to distinguishing the utility of individual signs, multiple signs in combination produce more complex decrements. Recommendations are made as to maximum sign density. The final task provides an assessment of signage in future IVHS driving environments. It points to the role of signage as one component of communication. A list of issues for future signage implementation is given for consideration as the Department moves to provide safe and efficient transport for the people of Minnesota into the 21st century.

This report highlights the findings of a project to determine the impact of traffic calming strategies on driver behavior, traffic flow, and speed. Researchers used a number of different approaches, including a literature search to determine results at a national level and local before-and-after studies in areas that implemented new traffic calming strategies. Researchers also compared an actual street before and after implementation of traffic calming devices to a driver simulation study of a street with and without traffic calming devices. Research results indicate that traffic calming can have a limited impact on average driver speed. The greatest impacts on speed often occur in reducing the number and speed of outliers, or those who travel at speeds greater than the 85th percentile speed. The report details the impact of different types of traffic calming strategies on traffic speed and volume.

This report summarizes the findings of a human factors analysis to determine the effects of advanced warning flashers (AWFs) on simulated driving performance. The Minnesota Department of Transportation sponsored the project. Researchers used the flat-screen simulator at the University of Minnesota Human Factors Research Laboratory to conduct experiments. They measured vehicle speed, braking, and acceleration/deceleration during simulated driving and visually observed stopping behavior. In addition, they analyzed responses to a post-test questionnaire. They created a 11.3-mile simulated driving environment with 10 signalized intersections and configured four experimental models: low speed limit (SL) of 50 miles per hour with no AWFs, low SL with AWF at each intersection, high SL of 65 miles per hour with no AWFs, and high SL with AWF at each intersection. Researchers set different vehicle-signal proximity intervals, with all green/ no yellow as the control, and zero seconds with the vehicle adjacent to the signal, two seconds, three-and-a-half seconds, or five seconds. With each model, they assigned two intersections each proximity interval, with the sequence of intersection proximity intervals ordered differently for each model. Each of 24 subjects completed duplicate driving trials with each model. The study revealed that, relative to intersections with no AWFs, drivers who encountered yellow signals at AWFs intersections: stopped more frequently at low SLs but not at high SLs, drove more slowly while approaching intersections with two and three-and-a-half second proximity intervals, and displayed less inconsistent behavior at intersections with short proximity intervals. Researchers concluded that AWFs assist drivers with decision-making behavior and promote safer driving behavior. They recommended field research to study and actual environment.

This project involved investigating the effect, if any, of rumble strips on stopping behavior at simulated rural-controlled intersections. Researchers used the wrap-around driver simulator at the University of Minnesota's Human Factors Research Laboratory for the project. Researchers varied the rumble strip type and the number of rumble strips and tested them on two different types of controlled intersections, two-way or four-way, and in the presence and absence of traffic. Results indicate that none of these manipulations seem to affect the point at which drivers stop at the controlled intersections or the point at which drivers start to slow down at controlled intersections. The research did reveal drivers brake more, earlier, when rumble strips are installed than they do if there are no rumble strips. Although they started to slow down at the same time and finished braking at the same time, there was more use of the brake earlier in the slowing down maneuver in the presence of rumble strips. Results also reveal that drivers brake more and earlier with full coverage rumble strips than they do with wheel track rumble strips.

This study analyzed the relationship between the size of the forward looking blindspot (FLB) produced by vehicles A-post (windshield frame), the speeds of two vehicles approaching an intersection at right angles, and driver behavior relative to a likely accident event. Researchers observed 28 volunteer participants directly and by four channels of on-board video cameras while they drove in a simulator at the Human Factors Research Laboratory. They noted the way that participants scanned the virtual environment and scored at four levels of scanning activity. They also tracked visual acquisition of the target vehicle and incidence of collision. Only 6.3% of the total fell into type one scanning (eyes fixed). Type II (eyes only) accounted for the highest incident rate at almost 44%. The study considered both as "inactive" forms of scanning. Target vehicle acquisition rate increased with the activity level of the scanning type. The target acquisition rate increased significantly from scanning level one to level two and from scanning level two to level three. There was not a significant increase in the acquisition rate from scanning level three to level four. Not surprisingly, collision rates decreased with increases in scanning level. Collision rates significantly dropped between scanning levels two and three and scanning levels three and four. Yield signs at intersections produced no significant correlation with acquisition rate, collision rate, or scanning level.

In this project, researchers investigated whether the results obtained in a before-and-after traffic calming experiment conducted in a driver simulator paralleled a real world before-and-after traffic calming study. The project also involved determining whether or not targeted traffic calming strategies resulted in reduced driving speeds. The report details the results of two simulator experiments on traffic calming. The first experiment examined traffic calming devices already installed on the stretch of Franklin Avenue between Chicago Avenue and Hiawatha Avenue in Minneapolis. A parallel before-and-after study occurred on the actual roadway. The second experiment examined the effects on driver speed of adding median islands, chokers, and plantings in a residential environment. Taken together, the two experiments show that the use of median islands, chokers, and plantings are likely to produce measurable reductions in traffic speed. The report recommends further research to discover how the specific placement or spacing of traffic calming elements would affect traffic speed. Further, the results obtained with the driving simulator parallel the direction of results obtained in the real world study of the urban environment of Franklin Avenue.

A comprehensive driver assistive system which utilizes dual frequency, carrier phase real time kinematic (RTK) differential global positioning system (DGPS), high accuracy digital geospatial databases, advanced automotive radar, and a driver interface with visual, haptic, and audible components has been used to assist specialty vehicle operators perform their tasks under these low visibility conditions. The system is able to provide a driver with high fidelity representations of the local geospatial landscape through a custom designed Head Up Display (HUD). Lane boundaries, turn lanes, intersections, mailboxes, and other elements of the geospatial landscape, including those sensed by automotive radar, are projected onto the HUD in the proper perspective. This allows a driver to safely guide his or her vehicle in low to zero visibility conditions in a desired lane while avoiding collisions. Four areas of research, are described herein: driver assistive displays, the integration of a geospatial database for improved radar processing, snowplow dynamics for slippery conditions, and a virtual bumper based collision avoidance/gang plowing system. (Gang plowing is the flying in formation of snowplows as a means to rapidly clear multilane roads.) Results from this research have vastly improved the performance and reliability of the driver assistive system. Research on the use of a specialized driver assistance system to assist specialty vehicle operators in low visibility conditions, including the design of a custom Head Up Display (HUD) projecting elements of the landscape in proper perspective. Driver assistive displays, the integration of a geospatial database for improved radar processing, snowplow dynamics for slippery conditions, and a virtual bumper based on collision avoidance/gang plowing system are discussed.

A driving simulation experiment was conducted to investigate auditory icons as side- and forward-collision avoidance warnings. The auditory warnings produced significantly faster mean response times than with no warning, and participants preferred a double-beep side collision warning over a single-beep warning. Researchers recommend a double-beep auditory warning similar to the double-beep of a car horn for side-collision avoidance and a forward-collision avoidance warning similar to two successive bursts of screeching tires.