Category Archives: Traffic and Safety

Optimal Sight Distances at Rural Intersections

A new study sponsored by the Minnesota Local Road Research Board has identified 1,000 feet as an optimal sight distance for allowing drivers to make better crossing decisions at rural intersections. Researchers used a state-of the-art driving simulator to examine drivers’ ability to judge traffic speed and gaps between cars at unsignalized intersections with varying sight distances.

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Design Standards for Unobstructed Sight Lines at Left-Turn Lanes

Positive offset left-turn lanes are one solution to improving left-turning motorists’ visibility of opposing through and right-turning traffic.

MnDOT is revising its Road Design Manual and seeks to incorporate more information, policies and design guidance regarding positive offset left-turn lanes.

Researchers from the University of Wisconsin’s Traffic Operations and Safety Laboratory reviewed safety performance data from research that examined left-turn offsets. They also consulted 23 state DOT road design guides to understand the extent of available guidance.

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Collaboration with Minnesota Zoo aims to conserve wildlife

Turtles and other wildlife are at risk along Minnesota roadways.

MnDOT is collaborating with the Minnesota Zoo on a new research project installing small animal exclusion fencing. The fencing is intended to redirect turtles (and other small animals) to culverts and bridges where they can cross the road safely.

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Smartphone App Alerts Drivers Exceeding Speed Limits on Curves

Researchers have developed a proof-of-concept curve speed warning system for use with mobile phones, a technology they hope car manufacturers might adopt for in-vehicle systems. The proof-of-concept system uses data from local road agencies on curve locations, speed limits and signage with geofencing to trigger cloud-based data alerts to road users driving faster than recommended speeds for curves.

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Leveraging Existing Inductive Loops to Classify Highway Vehicles

Researchers evaluated the use of existing inductive loop installations in Minnesota for vehicle classification. Results showed that inductive loops may be effective at identifying and classifying individual vehicles as they pass, but the system will require further refining for Minnesota use.

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Speed Notification System Warns Drivers Approaching Urban Work Zones

Using an innovative method to calculate vehicle trajectories and gather large amounts of driver data, researchers tested and evaluated the new Smart Work Zone Speed Notification system and determined that its messages successfully influenced drivers to reduce their speed. 

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Evaluating the Use of Central Traffic Signal Control Systems

MnDOT sought to determine the full range of intersection control information (ICI) currently used in the state and how it could best be made accessible for state transportation system needs. Researchers created the Regional Database of Unified Intersection Control Information, a machine-readable, cloud-based unified ICI system. They determined steps MnDOT could take toward more effective use of its central traffic signal control system, such as mitigating traffic disruption around construction zones and participating more fully in emerging technologies such as vehicle information systems and vehicle automation.

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Preparing Roads for Connected and Autonomous Vehicles

Proprietary technologies, industry competition and federal regulatory concerns are slowing the advent of defined standards for connected and autonomous vehicles (CAVs). Researchers investigated the state of CAV implementation to help local agencies begin preparing for the infrastructure needs of these vehicles. CAV-friendly options are considered for eight infrastructure categories. Since truck platooning is the likely first application of this technology, and optical cameras appear imminent as an early iteration of sensing technology, researchers suggest that wider pavement striping and well-maintained, uniform and visible signage may effectively serve the needs of CAVs in the near future while enhancing infrastructure for today’s drivers. 

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New project: Effectiveness of Teenage Driver Support System

The Minnesota Local Road Research Board (LRRB) has funded a follow-up study to determine whether a monitoring system it field tested for new drivers, called the Teen Driver Support System (TDSS), affected teenagers’ long-term driver behavior.

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