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Case Studies

Transportation agencies across the United States are using INVEST to evaluate and improve sustainability within their agency and on their projects.

Case studies focus on the general use of INVEST and its implementation and/or scoring practices. Some focus more on process/application, some focus on a few select criteria, some focus on the overall experience of using INVEST. Case Studies are developed by the agency which submits them, with review and input by FHWA.

Use the map and filters below to find case studies relevant to your projects and/or agency.

MDT - Focusing on Efficiency and Cost Savings

Lead Agency: Montana Department of Transportation (MDT)

INVEST Module: Operations and Maintenance (OM) (Version 1.1)


 Download the MDT INVEST Report (3,650 kb)

 Download the MDT Case Study (1,786 kb)

The Montana Department of Transportation (MDT) evaluated the agency’s operations and maintenance practices using two criteria from the INVEST Operations and Maintenance (OM) Module: OM-2 Electrical Energy Efficiency and Use and OM-3 Vehicle Fuel Efficiency and Use.  MDT focused on these sustainability areas because they are efficiency practices that can result in direct cost savings.  MDT scored 5 out of 15 for OM-2 and 11 out of 15 for OM-3.  MDT also conducted a benefit-cost analysis related to OM-4 Recycle and Reuse, evaluating a potential pilot for incorporating recycling at MDT rest areas in MDT District 1. 

Scoring of OM-2 Electrical Energy Efficiency and Use (5/15)

A major part of the scoring system is planning and documenting continuous progress for each criterion.

MDT lacked a plan for continuing energy efficiency efforts, which stalled in 2010 after original goals were met.  However, state-wide energy efficient building standards and energy monitoring helped MDT score points in this area.   More information on how MDT scored on each sub-criterion within OM-2 is provided below.

Set Energy Reduction and Renewable Energy Usage Goals (0/4) - MDT does not have a specific energy reduction goal.  However, in 2005, Montana established a statewide 15 percent reduction goal for 2015.  The reduction was enacted by legislation called the Renewable Power Production and Rural Economic Development Act. The goal can be met by generation facilities, purchase of Renewable Energy Credits (REC), or a combination of both.  All new MDT buildings and major remodels must meet the high performance building standards required by State Law.

Develop a Plan (0/4) - MDT does not have a written plan at this time.

Measure Progress and Monitor Performance (2/2) - Montana Department of Environmental Quality (DEQ) has a program called EnergyCAP, which tracks electricity usage for all State buildings, including MDT maintenance, operations, rest area, and headquarters buildings.

Employee Awareness Program (0/2) - Prior to 2010, MDT had a “Green Team” that provided employee awareness. The Green Team was a volunteer-based group that took comments from building users and implemented strategies for employee-based energy savings statewide. The committee was dissolved after the 2010 goal was reached.  MDT does not currently have a formal program.

Demonstrate Sustainable Outcomes (3/3) - MDT initiated seven energy efficiency projects at maintenance and headquarters buildings from 2006 to 2012 to meet the 20 percent energy use reduction goal for 2010. These projects involved upgrades to more efficient lighting, heating, ventilation, and cooling systems.  They included upgrading to condensing boilers, adding heat recovery ventilators , installing new chillers and upgraded controls, variable frequency drives on hot water pumps, new lighting, new air handling units, new variable air volume  boxes with reheat, and adding a new heat recovery loop from a data center.

Additional energy-saving efforts are ongoing at rest areas. Lost Trail Pass Rest Area in Sula, Montana uses a solar system to charge the batteries used for the electricity in the rest area reducing the time that the generators need to run.  Anaconda Rest Area in Anaconda, Montana has a wind generator that utilizes a deduct meter. Dearborn Rest Area in Wolf Creek, Montana utilizes an air to air heat pump to reduce propane usage.  Flowing Wells Rest Area in Cohagen, Montana has a new ground source heat pump system completely eliminating the need for propane.

Scoring of OM-3 Vehicle Fuel Efficiency and Use (11/15)

MDT demonstrates excellent sustainability for light-duty vehicle purchase and monitoring, but it missed complete scores with its heavy vehicle fleet. Measuring fuel efficiency of heavy vehicles is difficult due to diverse operating conditions. MDT did get credit for changing idling procedures, purchasing requirements and use of more efficient materials, thus reducing fuel use. More information on how MDT scored on each sub-criterion within OM-3 is provided below.

Set Fuel Usage Goals (2/4) – MDT has goals for the light-duty fleet, but not for the heavy-duty fleet and off-road equipment.

Develop a Fleet Management Plan (2/4) – MDT developed a plan that includes replacing vehicles with smaller alternatives that provide the same capability, purchasing vehicle transmissions that enhance fuel efficiency, implementing training and employee information measures to reduce vehicle idle time, and improvements in road de-icing procedures.

Test Alternative Fuels and Reduction Methods (3/3) - MDT investigated the use of alternative fuels such as CNG and bio-diesel. It was determined that the infrastructure does not exist in Montana to effectively support such vehicles. Fueling stations are not available near MDT facilities. MDT will continue to monitor this situation.

Measure Progress and Monitor Performance (2/2) - MDT monitors mileage and fuel usage for individual light vehicles using a spreadsheet that shows fuel mileage trends over the last four years by class of vehicle.

Demonstrate Sustainable Outcomes (2/2) - Although fuel efficiency fluctuated between 2010 and 2014, overall fleet mileage improved. During the same time period MDT was unable to purchase new light duty vehicles causing the fleet to age and accrue higher mileage, which directly affect fuel mileage.

Analysis of Costs and Benefits of Recycling at Rest Areas – OM-4

Montana has 48 rest areas scattered across the state on interstates and major highways. Trash collection is a significant percentage of maintenance costs at Montana rest areas. Recycling provides potential cost savings for refuse disposal. As part of this analysis, MDT reviewed other states’ rest area recycling practices and looked at costs and savings for implementing recycling at two high-use rest areas in Montana.

The success of recycling programs depends on ease of waste handling and the local market for recycled material. Some wastes are easier to recycle, such as aluminum beverage cans (aluminum cans sell for about $0.45 per pound). Recycling centers often take Type 1 and 2 plastics, but pay nothing for the product. Recycling of other plastics is less prevalent, especially at smaller centers. Paper and corrugated cardboard are also recyclable with little remuneration.

MDT contracts with local individuals as caretakers, who are responsible for collecting and disposing of rest area waste at local depositories, usually amounting to one or two bags of refuse per day. A few rest areas have dumpsters (4 to 5 yard) emptied periodically by commercial waste collectors.

The minimum one-time cost for a collection system (concrete recycling bins) is approximately $1,000. There are unquantifiable costs associated with collection and sorting by the rest area caretaker. The annual value of recyclables is probably between $365 and $730 dollars.

MDT determined that while the direct monetary benefits to MDT are small, the costs of instituting a recycling collection system are also small, and such an effort would enhance MDT’s green image.

Key Outcomes of Using INVEST:

  • As a result of the INVEST evaluation, MDT developed the following recommendations:
  • Maintain MDT’s excellent sustainability for light vehicle purchase and monitoring;
  • Consider implementing improvements to MDT’s processes for documenting MDT’s continuous progress toward sustainability;
  • Consider enhancing MDT planning to support continued energy efficiency progress; and
  • Consider conducting a complete MDT Operations and Maintenance scoring. 

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