Performance Data and Results:
These sources contain the performance data and results from the HTUF effort of developing, field testing, and validating the performance benefits of heavy-duty hybrids.

The environmental value of hybrid technology in medium- and heavy-duty vehicles is significant and has been documented extensively in both independent lab testing and field assessments. It is one of the few near-term technologies that can both reduce criteria emissions as well as improve fuel economy, thus contributing to energy security and meaningfully reducing greenhouse gas reductions while also reducing urban smog emissions.

Hybrids offer the benefit of being an additional “arrow in the quiver” of options needed to reduce some of the worst smog-causing (criteria) vehicular emissions – nitrogen oxides (NOx) and particulate matter (PM). Targeting hybrids in medium and heavy-duty trucks makes sense because while accounting for only about 6% of total on-road vehicles, they produce 60% of the NOx and 80% of the PM from this sector. Hybrids can reduce operational emissions beyond the level of the engine operating alone, meaning beyond an engine’s certified level.

The absolute emissions reductions from a hybridized system will vary by  duty-cycle – the daily mission profile the vehicle follows is important to how it performs. That said, hybrid medium and heavy-duty vehicles generally account for significant reductions over the emissions of the engine they are coupled to in all categories of criteria emissions.

In demonstration projects that have returned emission results, the hybrid systems – most of them diesel-electric hybrids – have demonstrated results that are far improved over conventional diesel alone. The first findings came from heavy transit buses and more recently from trucks. Note: global warming gas (GHG) emissions are also reduced by hybrids, together with criteria emissions. This is primarily due to fuel reduction, since each gallon of diesel fuel burned releases 22.2 pounds of GHGs. Therefore, each gallon of diesel NOT burned reduces  GHG emissions by the same amount.

Further reading:
Heavy-duty Hybrid Utility Trucks – HTUF Deployment Experiences and Results, (2007)
J. Tomic and B. Van Amburg, EVS-23, Anaheim, CA. Synopsis: The paper contains comparative performance data from the deployment of the 24 hybrid and 20 baseline utility trucks. Fuel consumption benefits, availability, service issues, and acceptance surveys are covered.

Pilot Hybrid Utility Trucks Assessment, (2007)
J. Tomic, Presented at Hybrid Truck National Meeting 2007, Seattle, WA, 2007. Synopsis: The presentation covers the results and data from the deployment of the 24 hybrid utility trucks.

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