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The Minnesota Speed Management Program (MSMP), a cooperative project between the Minnesota Department of Transportation and the Minnesota Department of Public Safety, was developed within the framework of the Minnesota Comprehensive Highway Safety Plan. The overall goal was to reduce the number of fatal and lifechanging crashes on Minnesota highways. The MSMP involved a speed limit adjustment—on 850 miles of Minnesota’s 55 mph highways the speed limit was increased to 60 mph. It involved increased speed enforcement—by State Patrol, county sheriffs, and local law enforcement—on selected highways. There were four waves of Enhanced Enforcement (one of six weeks, three of eight weeks) each followed by four weeks of Regular Enforcement. The MSMP involved extensive public education, organized by the Office of Traffic Safety, with approximately 10,000 public service messages presented on the radio. Two evaluation efforts were conducted. The University of Minnesota compared travel speed data and crash data obtained during the MSMP with historical data. Throughout the MSMP, there were decreases in the number of drivers traveling at least 10 mph above the speed limits—decreases of -28.7% on 2-Lane/2-Way Highways; -28.7% on 4-Lane Divided Highways; -42.9% on Rural Freeways; and -11.2% mph on Urban Freeways. The University’s evaluation also showed there were reductions in the numbers of fatal and life-changing crashes during the MSMP. MarketLine Research conducted the second evaluation, using telephone surveys, and found nine in ten drivers support the speed limit increase from 55 mph to 60 mph in both Metro and Greater Minnesota. The MSMP, in concert with other efforts that are part of the Minnesota Comprehensive Highway Safety Plan, resulted in reductions in the number of speeders on Minnesota Highways and reductions in the number of fatal and lifechanging crashes—making Minnesota’s roads safer.

After visiting a variety of stop-controlled intersections in the Twin City metro area, the researchers developed, with the aid of a computer simulator, two innovative intersection designs to improve safety at unsignalized intersections on four-land, divided highways. These innovative designs offer a number of advantages; however, due to funding difficulties, the researchers were not able to test the effectiveness of the designs in a real world setting.

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.

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 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.

A driving simulation experiment was conducted to research interventions to right-angle crashes at rural Thru-STOP intersections, which accounted for 71% of Minnesota fatal crashes in 1998, 1999, and the first half of 2000. The interventions caused drivers to reduce speed as they neared the intersection, and implies that 1) drivers are less likely to inadvertently run stop signs when slowing down further from the intersection, 2) making the intersection more noticeable improves driver safety judgment, and 3) speed reductions on the major road of an intersection produce greater reductions in stopping distances.

This report documents the evaluation efforts undertaken by the Minnesota Team. To complement the work undertaken by the independent government evaluator, Battelle, the Minnesota evaluation team focused on two specific areas of the evaluation: human factors and benefit-cost analyses. Human factors issues include driver acceptance, reduction in driver fatigue, the effectiveness of the driver interface, and the measurable changes in driver performance. The Driver Assistive System (DAS), which is under evaluation for the US DOT Specialty Vehicle Generation Zero Field Operational Test, is designed to provide a driver a means to maintain desired lane position and avoid collisions with obstacles during periods of very low visibility. This program is motivated by the fact that specialty vehicles often must operate under inclement weather conditions and associated low visibility situations. The DAS improves safety for the specialty vehicle operator by providing the necessary cues for lane keeping and collision avoidance normally unavailable during poor visibility conditions. The DAS may also improve safety conditions for the general public by facilitating all-weather emergency services, and in the case of snowplows, opening roads and keeping them passable in heavy weather for other emergency vehicles and the general motoring public.

In pursuit of unimpeded high peak traffic flow, the "Design Guidelines for Super Two Highways" (Ekem, 1998) suggested several treatments for the right side of the roadway. But the left side is where drivers experience great speed differentials between their own vehicles and oncoming traffic. The authors examined centerline treatments and possible recommendations for Super Two guidelines. The current US standard (12-ft lane/4-in. dashes) was compared with combinations of wider lanes, wider dashes, and buffer areas. With each of the centerline treatments examined, participants kept the left side of the vehicle in the approximate center of the lane. All treatments resulted in shifting the center of the lane farther from the centerline than it was in the standard condition. Two conditions appear to be most effective in keeping drivers away from the centerline: 1) 14-ft lanes with both longitudinal rumble strips and 4-in.-wide dashes marking the centerline, and 2) 12-ft lanes with 4-ft buffer marked by 4-in.-wide dashes. However, implementing any of the centerline treatments should result in vehicles driving farther from the centerline, thus making it less likely that drivers will meet an oncoming vehicle. Data were gathered in a driving simulator. Further testing should be conducted in real driving situations.

Drivers receive value from traveler information in several ways, including the ability to save time, but perhaps more importantly, from certainty, which has other personal, social, safety, or psychological impacts. This project aims to quantify travelers' willingness to pay for pre-trip travel-time information on alternative routes. Different from previous studies based only on stated preference surveys, the 117 participants in the current study actually drove real-world routes. Pre-trip travel-time information was provided in the field experiment to half the participants. Various data collection techniques were used including in-vehicle GPS units, pre- and post-experiment surveys, and travel diary. Results reveal that speed and efficiency are not the only dimensions on which people make route choices. Ease of driving, pleasantness, and the presence of information are also significant factors. Results from multinomial and rank-ordered logit models indicate that many travelers receive value of up to $1 per trip for pre-trip travel-time information. The value of this information is higher for commuting, special event trips, and when there is heavy congestion. The accuracy of the travel-time information is crucial - it is only useful if it is believed to be accurate.

The objectives of this study investigating Changeable Message Signs (CMS) were to determine whether or not CMS messages really work, whether or not they cause traffic slow downs, and whether or not they have an impact on traffic flow. The participants were 120 licensed drivers from three age groups--18-24, 32-47, and 55-65 years old.