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Green Fleet Initiatives

All vehicle procurement specifications will be reviewed and modified as necessary to ensure that the specifications are written in a manner flexible enough to allow the purchase or lease of alternatively fueled (AFV) or electric drive-train vehicles. The Division will identify vehicles that can be reasonably replaced with more sustainable, higher miles per gallon (30-35 mpg), lower or zero-emission (ZEV), alternative fueled, flex-fueled (E85), and more efficient types of vehicles. In addition to establishing motor pools, the following Green Fleet initiatives should be considered in the replacement, purchase of new and / or leasing of vehicles:

Fuel Economy

It is important for fleet managers who provide on-site fueling services, automatic fuel dispensing systems and other fueling services to be familiar of several performance measures; average fuel consumption (miles per gallon) by vehicle and by class, fuel cost per mile, fully burdened rate per gallon of fuel, month-end inventory in dollars and gallons, and percentage of alternative fuel used versus petroleum-based fuels.

In FY 2008, the Department suggested that the Commissioners of St. Mary's County consider alternatives in future fleet acquisitions in order to avoid using inefficient retired Sheriff patrol vehicles as the primary source for motor pool vehicles. A fuel economy in the top 30% of their vehicle class as listed under EPA size class on the U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy and the U.S. Environmental Protection Agency maintained web site.

In FY 2010, an in-house fuel economy analysis was performed on a portion of the County's gasoline and diesel fleet. The STS Transit system buses averaged 8 miles per gallon and the Office of the Sheriff patrol vehicles averaged 14 miles per gallon.

Minimum Emissions Standards

A minimum emissions standard for each vehicle class for which the County has a procurement specification for and includes such a standard in any new vehicle procurement specifications. This emission standard shall be based on EPA designations of LEV, ILEV, ULEV, and ZEV.

Alternative Fuels

Replacement of a vehicle with an alternate fuel model will be done whenever feasible, particularly medium and heavy duty vehicles. Examples of other solutions include the possible use of: bio-fuels - ethanol, bio-diesel; natural gas - compressed (CNG) and liquefied (LNG) or even blended with hydrogen; electric technology; propane converted from standard gasoline vehicles; shared vehicles and satellite motor pools; hybrids - diesel and gasoline electric, hydraulic; PHEV (Plug in Hybrids) - gasoline and diesel electric; stacked technology - hybrids on bio-fuels and PHEVs on bio-fuels. Use of Ultra Low Sulfur Diesel (ULSD) can reduce emissions up to 10 percent. (Also, refer to the MD Task Force on Renewable Alternative Fuels Final Report dated December 31, 2007).


Where practical, larger vehicles should be downsized based upon vehicle usage and job responsibilities.

Diesel Retrofits

In order to help contribute to improved air quality, significant cost-effective reductions in the emission of particulate matter, hydrocarbons (HC), carbon monoxide (CO) and oxides from nitrogen (NOx) can be achieved. In order to assist with the implementation of retrofit projects, Federal funding may be available through a low-cost revolving loan program administered under the Diesel Emissions Reduction Program (DERP). According to The National Clean Diesel Campaign Progress Report, improved air quality can be attained through the Five R's of Retrofit as follows:

Rebuild. Rebuild core engine components after 3-4 years to manufacturer's original specifications to return emissions performance to the original design level.

Refuel. Use of Ultra-low Sulphur Diesel (ULSD) can lower emissions, as can other renewable fuels and fuel products such as biodiesel and emulsifiers (or additives that improve properties of the base fuels and/or lowers combustion temperatures).

Retrofit. Installation of exhaust emissions control technologies such as diesel particulate filters (DPF), diesel oxidation catalysts (DOC), lean NOx catalysts, exhaust gas recirculation (EGR) and selective catalytic reduction (SCR) in heavy equipment and buses.

Repower. Replacing the older engine in diesel powered equipment with a newer or cleaner engine or replacing a diesel engine with one that can use alternative fuels can dramatically reduce emissions.

Replace. Replacing entire vehicles or equipment may be the best option for some of the oldest and heaviest emitting fleet vehicles. Hybrids

The Transportation Division plans to evaluate hybrid-electric systems for possible recommendation when replacing bucket trucks, transit buses and refuse vehicles and the use of EPA-certified E-85 conversion kits. A pilot project on an unmarked squad car (Crown Victoria) and testing on additional vehicles should be performed prior to a wider program of retrofits on all applicable Office of the Sheriff vehicles.

Bio-based Product Use

Bio-Preferred is a Federal program that aims to increase the purchase and use of bio-based products. Bio-based products are made from biological or renewable agricultural materials like plant, animal, marine or forestry ingredients. The County shall utilize products and material made from bio-based materials to the maximum extent practical without jeopardizing the intended end use or detracting from the overall quality of the fleet. All supplies and materials shall be of a type and quality that conform to applicable Federal specifications and standards. Examples of bio-based products for vehicle maintenance use include; hydraulic fluids, penetrating lubricants, diesel fuel additives, multipurpose lubricants, degreasers, lube chain lubricants, glass cleaners, chain bar lubricants and various cleaning products.

Based on the 2010 difference of approximately $0.43 per gallon, the County Highways Pilot Bio-Diesel Program will be limited to an FY 2011 program goal of utilizing 10,000 gallons per year through a joint fueling partnership with the local State Highway Administration.

Minimum Vehicle Miles Traveled (VMT)

For vehicles that operate on fixed routes, such as maintenance routes and meter reading routes, route optimization should be employed. In general, all routes should be planned to optimize the route and trips chained together to reduce required travel time and distance. Supervisors should:

Encourage meetings at centralized locations to reduce necessary travel;

Encourage and enable alternate meeting methods, such as conference calls, to reduce the number of necessary trips;

Vehicles shall not be left idling unless a running engine is necessary to protect public safety, to prevent harm to contents of the vehicle, run auxiliary equipment in performance of a job, or to maintain health of occupants while performing duties. Vehicles are not to be left idling for extended periods; and

Where applicable and/or appropriate, suggest employees use alternative modes of transportation, such as buses, light rail, carpools, vans, or bicycles.

Idling Reduction

Increased awareness and promotion of idling reduction guidelines to improve local air quality, increase fuel efficiency, reduce engine "wear and tear", save maintenance expenses and help lower green house gas emissions is recommended. Studies have shown that idling of vehicles consumes approximately 17% of the fuel that a vehicle has on board, which equates to between 0.6 gallons per hour for an averaged sized gasoline engine and 0.8 gallons per hour for an idling diesel truck engine. For trucks, idling engines operate at 3-11% efficiency, compared to 40% efficiency while driving. Installing diesel-fired heaters in trucks to warm coolant, engine block and hydraulic reservoirs before shift-start can also eliminate early-morning idling. For dedicated Sheriff vehicles, idling is the most significant out-of-sight variable in fuel and oil consumption. Guidelines generally establish maximum idling times (ie.5-30 minute duration) for different vehicle and equipment types, seasonal variations, and exemptions for transit and emergency operations

Retread Tires

The Vehicle Maintenance Division purchases about 800 tires per year at an average cost of between $150-$200 per tire, with off-road and tractor tires costing between $350-$500 each. Although some retread tires are in inventory, due to the current mix and utilization of the fleet, very few are utilized. It is estimated that for each re-treaded tire purchased, that approximately 15 gallons of crude oil could be saved, compared to the oil required to manufacture a new tire.

Environmentally Preferable Purchasing (EPP)

The use of environmentally friendly products is highly encouraged as is supporting the County's recycling program by buying recycled products. The EPA has several publications that recommend recycled-content levels to assure environmentally preferable purchasing is achieved. At a minimum, the DPW&T Transportation Division will make an effort to purchase re-fined lubricating oils, retread tires, tires containing post-consumer recovered rubber and bio-based products, wherever they are reasonably available and meet vehicle manufacturer specifications.