Materials and Construction, Policy and Planning

New Project: Development of Pavement Condition Forecasting for Web-based Asset Management for County Governments

September 20, 2018 mndotresearch Leave a comment

Many counties have incomplete roadway inventories, but lack asset management programs, which are often cost-prohibitive and require advanced technical training and staff to maintain. The Upper Great Plains Transportation Institute at North Dakota State University (NDSU), has developed a low-cost asset inventory program called the Geographic Roadway Inventory Tool (GRIT). The program, which is currently available to North Dakota counties, will be offered to all Minnesota counties following further development and testing by the Minnesota Local Road Research Board.

Background

NDSU created the asset inventory program as the first step for asset management to allow local roadway managers to document and understand their existing infrastructure using the latest mobile technology and Geographic Information System technology.

The goal of the research study is to expand the program to include roadway forecasting based on the American Association of State and Highway Transportation Officials(AASHTO) 93 model with inventory, pavement condition and traffic forecasting data.

Existing input data from GRIT, such as pavement thickness, roadway structural information and construction planning information, will be spatially combined with current Pathway pavement condition and traffic data from MnDOT to automatically forecast the future condition and age of roadways using the AASHTO 93 model. This forecasting model will then allow roadway managers to use this information with comprehensive GIS web maps to prioritize roadways in construction schedule or multi-year plans.

Objective

The additional information contained in the pavement forecast system will allow county roadway managers to prioritize projects that can benefit from lower cost pavement preservation activities and understand how long roadways can last before a high cost reconstruction must take place. The online GIS output maps will also enable the public to see what projects will be conducted on a year-to-year basis.

Project scope

The research team will work with Beltrami, Pope, Faribault, Pennington, and Becker counties and the city of Moorhead in Minnesota to research, develop, test and implement an additional forecasting function of the existing asset management program. This will be done using the AASHTO 93 empirical model to calculate a future pavement serviceability rating (PSR) based on the existing pavement structure and age, forecasted traffic and the latest pavement condition. While existing pavement structure and age information will come from data entered into the GRIT program by counties, processes and procedures will be researched and developed to automatically access pavement condition and traffic data from MnDOT and geospatially combine it with inventory data.

With pavement forecast information, county roadway managers will be able to better understand which roadways will deteriorate first and which will benefit from more effective, low-cost maintenance programs rather than full-depth reconstructions. The model will not forecast suggested future projects or project costs, but rather just output the future condition of the roadways on a yearly basis. The AASHTO model can be applied for both flexible and rigid pavement sections.

Watch for new developments on this project. Other Minnesota research can be found at MnDOT.gov/research.

Maintenance Operations

New Project: Guide for Converting Severely Distressed Paved Roads to Unpaved Roads

September 19, 2018 mndotresearch 1 Comment

Local agencies are increasingly looking at converting low-trafficked paved roads to gravel at the end of their life span to make budgets stretch. However, agencies have few resources to guide them in this process.

The Minnesota Local Road Research Board recently approved funding for a guidebook on effective practices for converting severely distressed paved roads to unpaved roads. The document will help engineers select roads for conversion, safely conduct conversions and communicate the rationale to the public. No such published document currently exists.

Montana State University researchers has been hired to develop the guidebook based on needs the research team previously identified in the National Cooperative Highway Research Program’s Synthesis 485, “Converting Paved Roads to Unpaved. The guidebook, anticipated to be published in late 2019, will include flowcharts that guide practitioners through decision-making processes. A companion webinar is also planned.

The guidebook will be divided into chapters, which will cover:

Methods to determine if a road is a candidate for conversion and determine the existing road materials and condition.
Methods to convert a road from paved to unpaved.
Methods to assess the life-cycles cost of construction and maintenance of the unpaved road.
Tools to effectively inform and communicate with the public
Safety implications of converting a severely distressed paved road to an unpaved road.

Background
While low- volume roads are typically identified as having an annual average daily traffic (AADT) of less than 400, roads that are appropriate candidates for conversion will typically have an AADT of less than 150.

These roads are often used by agricultural and extraction industries or to access homes and recreational areas. The type of road users, traffic patterns and vehicle types are all factors that need to be considered in the decision to unpave a road. Other factors include road condition, safety, agency maintenance and maintenance capabilities, as well as a life-cycle cost comparison of maintenance options (continued maintenance of the deteriorating road, rehabilitation of the paved road or conversion to an unpaved surface).

According to the research team, very limited information is available about converted roads, and what information is available often comes in the form of newspaper articles and anecdotal accounts of road conversions.

The document will serve as a formal and peer-reviewed information source. The use of the guide and acceptance of the practice of converting from paved to unpaved surfaces (unpaving) where warranted will provide a case for the acceptance of road conversions as another low-volume road management strategy.

Watch for new developments on this project. Other Minnesota research can be found at lrrb.org and MnDOT.gov/research

Environment

New Project: Re-Using Water at Safety Rest Areas and Truck Stations

September 14, 2018 mndotresearch Leave a comment

Water is being drawn out of the state’s aquifers faster than it is being replenished, so public agencies like MnDOT are increasingly interested in figuring out how to reduce water usage.

A two-year research project underway at MnDOT is investigating how the agency can re-use wastewater at its safety rest areas and truck-washing stations. In addition to preserving groundwater, MnDOT hopes to reduce utility and septic system costs.

MnDOT owns and operates over 1,000 buildings, including 68 safety rest areas, 137 truck stations, 18 regional/headquarters maintenance sites and 15 weigh stations and truck scales.

These facilities either discharge their wastewater to a subsurface sewage treatment system or a wastewater treatment plant.

Truck station with vehicles in parking lot — Maplewood Bridge Truck Station

Researchers from the University Of Minnesota’s Onsite Sewage Treatment Program have been hired to investigate the potential avenues for wastewater re-use at MnDOT. They will consider when re-use makes sense from a regulatory, environmental, economic and management perspective; recommend the most appropriate applications for reuse and identify any challenges with implementation.

Potential benefits include:

Preserve ground and drinking water for potable drinking.
Reduced life-cycle costs in areas where low-producing wells could meet drinking water needs while reused wastewater could be used for toilet flushing and equipment wash-down.
In areas with municipal water, lower water utility costs.
Increased longevity of septic systems due to decreased loads.

As the state, counties, or cities construct new facilities or upgrade existing ones, this research will provide insight into what options are readily available to reduce water consumption and improve water efficiency. If these types of reuse systems are demonstrated by MnDOT, then they could lead to usage by other properties across Minnesota.

Watch for new developments on this project. Other Minnesota research can be found at MnDOT.gov/research.