Safety

This Technical Summary pertains to Report 2023-26, “User-Centered Smart Traffic Sign Development Study,” published June 2023.

This flyer pertains to report 2016RIC10, Intersection Safety Technologies Guidebook.

This presentation template pertains to report 2015RIC04, Younger Drivers Toolkit for Local Agencies.

This one-page brochure pertains to report 2015RIC04, Younger Drivers Toolkit for Local Agencies.

This Technical Summary pertains to Report 2023-27, “Deployment of a Snowplow Driver-Assist System,” published June 2023.

This Technical Summary pertains to Report 2023-23, “Influence of Autonomous and Partially Autonomous Vehicles on Minnesota Roads,” published May 2023.

In Minnesota snow presents a special problem for rural mailbox installations. So, Minnesota Department of Transportation (Mn/DOT) developed cantilevered mailbox support designs. Recent studies had shown that certain rural mailbox installations easily penetrated the passenger compartment of an impacting vehicle. These same studies pointed out that a large number of people are seriously injured or killed each year as a result of mailbox collisions Therefore, Mn/DOT initiated full scale crash test to ascertain the crashworthiness of its cantilevered design. The study results were: 1. The change in vehicle momentum was below the recommended limit. 2. The test vehicle remained upright with no tendency to spin out or roll over. (The four by four wood vertical support was not hit . Studies by others adequately document vehicle/post interaction) . 3. The windshield was broken in each test. However, no part of the test article penetrated into the passenger compartment. 4. There was no appreciable difference between the support designs- The study concluded that the Mn/DOT cantilevered designs are acceptable in terms of nationally recognized criteria. Some precautions are also given as to use and placement of the supports.

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.

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.

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.