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Flaggers protect workers by providing temporary traffic control and maintaining traffic flow through a work zone. They are often the first line of defense to stop distracted, inattentive, or aggressive motorists from intruding into the work area. This project aims to develop an automated intrusion detection system to alert drivers who are unsafely approaching or entering a flagger-controlled work zone. A human factors user needs assessment found maintenance workers preferred a modified traffic signal to feature the alert system due to flagger risks of being in the roadway and drivers failing to stop and remain stopped when presented with the STOP side of the flagger sign. A modified traffic signal that could be operated using a handheld remote was developed. The low-cost embedded electronics on the traffic signal enabled it to track trajectories of nearby vehicles, detect potential intrusions, and trigger audio-visual warnings to alert the intruding driver. Usability testing in a simulated driving test found poor expectancies and stopping rates of the traffic signal-based alarm system compared to a traditional flagger but did demonstrate evidence that drivers may be less likely to stop and remain stopped with the flagger STOP sign than the red ball indicator of the traffic signal. Furthermore, some drivers corrected their initial stopping error after triggering the auditory alarm of the traffic signal. A follow up test found improved performance with the alert system incorporated into an audiovisual enhanced STOP/SLOW flagger paddle. Testing of the developed sensor system found the system capable of simultaneous multi-vehicle tracking (including estimation of vehicle position, velocity, and heading) with a range of up to 60 meters and angular azimuth range of 120 degrees and correctly detecting all test intruding vehicles.

Snowplow operators are often tasked with clearing snow from roadways under challenging conditions. One such situation is low visibility due to falling or blowing snow that makes it difficult to navigate, stay centered in the lane, and identify upcoming hazards. To support snowplow operators working in these conditions, University of Minnesota researchers developed a snowplow driver-assist system that provides the operator with visual and auditory information that is suitable for low-visibility situations. A lane-guidance system uses high-accuracy Global Navigation Satellite System (GNSS) and maps of the roadway to provide information to drivers about their lateral positions. A forward-obstacle-detection system uses forward-facing radar to detect potential hazards in the roadway. The design of the system, and in particular its interface, is guided by extensive user testing to ensure the system is easy to understand, easy to use, and well liked among its users. The system was deployed in two phases over the 2020-2021 and 2021-2022 winter seasons. In total, nine systems were deployed on snowplows across Minnesota, four in the first winter season and an additional five in the second. Participating truck stations represented all eight MnDOT districts as well as Dakota County. Over the course of the deployment, additional user feedback was collected to identify system strengths and areas for improvement. The system was found to be a cost-effective addition to snowplows that increase driver safety, reduce plow downtime, and increase driver efficacy for plowing operations, thus providing support to operators working in demanding, low-visibility conditions.

Work zones present an increased risk to drivers and the work crew. To mitigate these risks; this study investigated the potential effects of in-vehicle messages to communicate work zone events to the driver. The researchers conducted literature reviews on risks imposed by work zones; along with design guidelines for any in-vehicle messaging system. The researchers then conducted a work zone safety survey to illustrate driver attitudes in Minnesota toward work zones; along with smartphone use and in-vehicle messages through smartphones. The survey found that a significant number of drivers make use of smartphones in the automobile; and they placed these smartphones in various locations throughout the vehicle. The survey was followed by a driving simulation study that tested drivers in two different types of work zones. Participants drove through these work zones three times; each with different messaging interfaces to communicate hazardous events to the driver. The interfaces included a roadside; portable changeable message sign; a smartphone presenting only auditory messages; and a smartphone presenting audio-visual messages. There was better driving performance on key metrics including speed deviation and lane deviation for the in-vehicle message conditions relative to the roadside signs. Furthermore; drivers reported significantly less mental workload and better usability; work zone event recall; and eye gaze behavior for the in-vehicle conditions relative to the roadside sign condition.

The goal of the study was to examine the influence of in-vehicle signing (IVS) pertaining to four types of changing driving conditions and determine the utility and potential safety costs associated with the IVS information. Signage displayed on a personal navigation device was presented for specific zones within the simulation to assist drivers preparation for transitioning to new driving conditions ahead. These zones included: speed zone changes within the same roadway, notification of school zones, notification of work zones, and notification of curves. Driving performance measures known to be related to distraction as well as subjective usability and workload measures were used to help identify potential distraction associated with the IVS information. Moreover, risk analysis was conducted to evaluate the safety associated with IVS technology compared to the known safety levels with standard roadside signage. The objective measures collected in this study (both driving performance and risk analysis) indicated that implementing IVS technology would impact driving performance in the following manner: · When IVS was deployed in the absence of external signs, speeding behavior significantly increased relative to baseline levels. IVS technology was not observed to impact speeding behavior when external signs were also present. ·Risk analysis suggested that IVS technology (when used in conjunction with external signs) can improve the safety associated with frontal-impact crashes; however, risk analysis proved that safety across all crash types was significantly reduced below baseline levels when IVS was used without external signs. Moreover, subjective usability results reinforced the driving performance findings.

Each year, there are over 500 fatal crashes in work zones in the U.S., with over 100 road construction workers killed on work sites (NSC, 2011; FARS, 2011). Speed and distraction are among the top contributing factors to work zone crashes (Garber & Zhao, 2002; Mountain, Hirst, & Maher, 2005; Wilson, Willis, Hendrikz, Le Brocque, & Bellamy, 2006). The purpose of this study was to investigate the impact of different types of speed enforcement methods on driver attention in work zones. The investigation not only examined enforcement methods currently used in Minnesota, but also examined how implementing automated speed enforcement (ASE), which is not currently used in Minnesota, may influence driver attention and behavior in simulated work zones. Overall, the results do not appear to support the hypothesis that ASE without dynamic speed display sign (DSDS) improves driver attention in work zones. There is some evidence, however, that drivers did heighten their visual attention in work zones with ASE+DSDS enforcement. Drivers fixated on the secondary task display less frequently in the ASE+DSDS condition compared to other enforcement types while they traveled in the downstream portion of the work zone. The largest effects of the study were found among the age groups, with younger and older drivers exceeding the speed limit most often and varying their speed slightly depending on the type of enforcement present. Middle-aged drivers exhibited the greatest speed control and tended to abide by the speed limit to the same extent regardless of the type of enforcement present.

A novel infrastructure design known as the J-turn intersection reduces the risk of serious and fatal crashes at thru-STOP intersections through decreasing points of conflict at an intersection by restricting crossing movements from the minor road. Despite their demonstrated safety efficacy, J-turns have not been met with uniformly positive support. In this research, we first examine novice driver baseline attitudes and driving behaviors on J-turns using a driving simulator study. Results demonstrate that critical errors are decreased with driving exposure to the J-turn; however, attitudes toward J-turns are not improved by exposure alone. A series of studies then evaluates the efficacy of various messaging strategies and educational materials on improving attitudes toward J-turns. The findings from these studies identify that the use of both educational materials and persuasive and customized messaging strategies is an effective method for increasing acceptance of J-turns across diverse resident populations (i.e., rural, suburban, and urban) and among stakeholders in Minnesota. This work demonstrates the importance of the role of proactive educational programs and community initiatives in promoting the acceptance and buy-in toward novel roadway treatments, such as J-turns, among diverse drivers, communities, and stakeholder groups.

Teenage drivers are at a disproportionate risk of fatal and serious injuries due to motor vehicle crashes. A Field Operational Test (FOT) funded by MnDOT used the Teen Driver Support System (TDSS) smartphone application to collect real-time driving performance data from a cohort of approximately 300 teen drivers, recruited in early 2013, who were monitored over a 12-month period after licensure. Study results showed the TDSS application's success in reducing instances of speeding for the two groups that received feedback, compared to teens who received no coaching or parental involvement, was influential in reducing kinematic driving events, e.g., hard braking. This five-year follow-up investigation of the long-term outcomes of the TDSS FOT cohort aimed to determine the frequency of state-recorded traffic citations and crashes along with these drivers' self-reported driving behaviors and attitudes. Of the original cohort, 251 agreed to be contacted for future studies and 150 were successfully recruited into the follow-up study. A re-examination of the FOT risky driving distributions divided into tertiles (low, moderate, high) found overdispersion of control group teens in the high risky tertiles compared to the two TDSS intervention groups, particularly for speeding-related behaviors and texting. The tertile risk level of early risky driving (e.g., speeding, hard braking) was found to significantly predict long-term safety outcomes for traffic violations/tickets. However, the sample size for crashes among the over sample was too small to determine if the mediating effect of the TDSS on early risky driving resulted in long-term reductions in crashes.

Decisions made regarding driver sight distance at rural intersections are complex and require considerations for safety; efficiency; and environmental factors. Sight distance; cross-traffic velocity; and vehicle placements significantly affect driver judgment and behavior at these intersections. A series of rural; two-lane thru-STOP simulated intersections with differing sight distances and traffic speeds were created and then validated by county and state engineers. Experimental data from 36 participants in a time-to-collision (TTC) intersection crossing judgment task and a rural highway thru-STOP intersection driving simulation task was analyzed to clarify the influence of rural thru-STOP intersection characteristics on driving performance and decision-making. Results demonstrated that longer sight distances of1;000 ft. and slower crossing speeds (i.e.; 55 mph) were more accommodating for participants attempting to select gaps and cross from the minor road; corresponding with (1) lower mental workload; perceived risk; difficulty; and anxiousness; and (2) better performance in terms of estimated crash rate; and larger TTCs. Second; longer distances of 1;000 ft. appear to aid drivers' responsiveness on the main road approaching an intersection; specifically when another driver on the minor road runs the stop sign. Minor road drivers positioned close to the roadway at the stop sign; compared to standard stop bar placement; tended to help reduce the speed of main road drivers. Overall;results demonstrated a systematic improvement in the performance of both minor and major road drivers with the implementation of a1;000-foot sight distance at rural thru-STOP intersections.

sed a multifaceted approach to improving compliance to the Minnesota crosswalk law in Saint Paul; Minnesota; including: (1) education; (2) measurement; (3) enforcement efforts; (4) social norming; and (5) engineering treatment. The multifaceted activities were planned and implemented in Saint Paul with city traffic engineers and enforcement officers. The study initially observed 32% yielding and frequent multiple threat passing at 16 unsignalized; marked crosswalks throughout Saint Paul; measured through staged pedestrian crossings by the research team. A program was implemented that used a phased treatment approach of disseminating educational materials; conducting four waves of high visibility enforcement (HVE); displaying yielding averages on feedback signs across the city; and introducing low-cost engineering solutions through in-street signs. The results demonstrated a significant impact from education; HVE; and engineering to increase yielding to as high as 78% at enforcement sites and 61% at untreated sites. Multiple threat passing was also reduced. Overall; the study demonstrated that the HVE program and combined low-cost engineering were effective at improving compliance to the crosswalk law.

Work zone intrusions represent a significant safety risk to workers. To help better understand these situations, the Minnesota Department of Transportation partnered with the University of Minnesota to create a method to document intrusion events. This information provides a deeper understanding of the circumstances under which these events occur and enables data-driven decision making when considering ways to reduce or mitigate work zone intrusions. This work focuses on the development of a mobile smartphone app that allows workers to report intrusions from the field immediately after they occur, allowing for timely and accurate intrusion reporting. The work zone intrusion mobile app is developed using an iterative, user-centered design process that solicits feedback from work zone personnel, supervisors, and work zone safety stakeholders at every step in the process. The app uploads completed report data to the existing eSAFE system, allowing for a single repository of collected intrusion report data. To support deployment of the system, training workshops and supporting training and communications materials are created for distribution among users. Throughout the development and deployment of the app, user feedback shows that the app is easy to use and well liked.