All posts by mndotresearch

Refining Max-Pressure Traffic Signal Control to Improve Traffic Flow

Effective traffic signal control technologies facilitate optimal traffic flow and travel time. Building on previous research, this project made significant progress toward field implementation of a novel adaptive signal control technology. This research phase demonstrated the max-pressure traffic signal algorithm can successfully integrate into Hennepin County traffic signal hardware and respond to changing traffic conditions in real time, providing confidence to move to the next step and test the system in the field. 

Continue reading Refining Max-Pressure Traffic Signal Control to Improve Traffic Flow

Developing Technology to Prevent Vehicles from Running Red Lights 

Crashes that result from vehicles driving through red lights are often very serious because they are typically right-angle or side-impact crashes. While newer vehicles have many standard safety features such as lane departure warning and brake assistance systems to support drivers, they do not have technologies to help prevent driving through red lights. This project developed an algorithm that integrated traffic light phasing information with GPS data to warn drivers when they were approaching a red light, providing valuable driver assistance and improving traffic safety and efficiency. 

Continue reading Developing Technology to Prevent Vehicles from Running Red Lights 

Comparing the Effectiveness of No Right Turn on Red Sign Types at Traffic Signals

Preventing right turns on red at traffic signals is a generally effective pedestrian safety measure. But when pedestrians are absent, allowing right turns on red can improve traffic flow. Unlike static signs that prohibit right turns on red, dynamic No Right Turn on Red (NRTOR) signs can be activated when pedestrians are present. Comparing driver compliance with dynamic and static signs indicated that each sign type may have its own benefits. 

Continue reading Comparing the Effectiveness of No Right Turn on Red Sign Types at Traffic Signals

Assessing Reliability and Resilience on Freeway Corridors

Drivers and businesses benefit from a freeway network that is predictable and able to withstand disturbances such as construction, incidents and poor weather. To provide a high level of service on freeways, traffic managers monitor and assess traffic flows and speeds under various conditions. In this project, investigators analyzed and identified the most vulnerable portions of the Twin Cities freeway network and enhanced an analysis tool to provide better estimates of travel-time reliability and operational resilience. 

Continue reading Assessing Reliability and Resilience on Freeway Corridors

Repairing In-Water Bridge Supports Using Innovative Methods and Materials

In recent years, advancements in bridge repair techniques and technologies promise to offer more options for strengthening an existing bridge’s in-water piles, eliminating the need to reroute both water and traffic. This project investigated other states’ experiences with several products on the market and provided an opportunity for Minnesota’s engineers to evaluate two vendors’ systems on a bridge in need of restoration. 

Continue reading Repairing In-Water Bridge Supports Using Innovative Methods and Materials

Understanding the Performance of Road Base Stabilization Additives

Full-depth reclamation (FDR)—an effective and efficient pavement reconstruction method—can be made even more sustainable by strengthening the road base. Laboratory and field testing of proprietary stabilizers used to amend FDR material illustrated improvements in pavement stiffness and economic benefits over time. New pavement design standards for base stabilizers can guide road engineers in choosing the optimal products for sustainable roads.

Continue reading Understanding the Performance of Road Base Stabilization Additives

New Smartphone App Uses GPS Technology to Warn Drivers of Lane Departures


Preventing vehicles from drifting out of traffic lanes is a top safety priority for transportation officials. An ongoing research project has produced a smartphone app that alerts drivers when their vehicles drift from a lane. The current phase of the project improved upon earlier versions of the app by adding GPS and significantly increasing the effectiveness of lane departure detection.

Continue reading New Smartphone App Uses GPS Technology to Warn Drivers of Lane Departures

Designing Channelized Right-Turn Lanes to Increase Pedestrian and Cyclist Safety

The use of channelized right-turn (CRT) lanes at intersections can improve driver safety and traffic mobility but can be challenging for bicyclists and pedestrians, particularly those with sight or other impairments. This project examines the current practice of CRTs to identify design solutions and mitigation strategies to better accommodate the safety and accessibility needs of all road users.

Continue reading Designing Channelized Right-Turn Lanes to Increase Pedestrian and Cyclist Safety

Reusing Local By-Products to Create Sustainable Roadside Soil 

Vegetated roadsides in Minnesota help control stormwater quantity and pollutant levels before the water reaches lakes, streams and communities. Because leftover soil from road construction generally does not support filtration and plant growth, MnDOT and local engineers have continued research to identify organically rich, locally available industrial by-products to amend the soil. Engineered soil mixes with materials such as dredge sand, coarse street sweepings and ash sawdust show high potential for providing a sustainable, efficient solution. 

Continue reading Reusing Local By-Products to Create Sustainable Roadside Soil 

Safety Considerations Associated with Driverless Shuttles

Driverless vehicles present an enticing opportunity for increased traffic safety and reduced labor costs. However, technical issues and concerns remain regarding the interaction between driverless vehicles and human drivers. This project included observing and analyzing the interactions of a driverless shuttle and other road users in a pedestrian-heavy area to develop strategies for decreasing potential threats. Increasing the speed of the driverless shuttle and displaying clearer electronic messaging on the back of the shuttle could improve safety challenges.

Continue reading Safety Considerations Associated with Driverless Shuttles