Because of their efficiency and durability, diesel engines are the workhorse of the U.S. economy and play an indispensable role in transportation, agriculture, construction and mining, as well as other key sectors.

Advances in diesel engine technology, as well as fuel and exhaust treatment systems, will make new diesel vehicles virtually emissions-free within a decade. According to the U.S. Environmental Protection Agency (EPA), by 2030 total emissions from diesel trucks, buses and off-road equipment will have been slashed by 80 percent compared to 2000 levels thanks to new regulations that began taking effect in 2007.

However, these new clean diesel advances do not affect the approximately 11 million engines in use today. Fortunately, the same clean diesel technologies that will power the next generation of diesel vehicles and equipment can be applied to some older engines – reducing emissions by up to 90 percent.

States developing clean air plans and cities looking for emissions reductions will find that diesel retrofit offers one of the most cost-effective solutions for achieving real and immediate air quality benefits. Diesel retrofits –broadly defined as replace, rebuild, refuel, retrofit and repower – offer a number of air quality benefits, however the economic benefits are less clear. Large operators may capture the good will and economic value of good corporate citizenship more readily than small operators that face few direct economic or market pressures related to their environmental performance. The federal government provides significant funding for diesel retrofit through a number of programs including the Diesel Emissions Reduction Act, the Congestion Mitigation and Air Quality (CMAQ) Improvement Program and Environmental Quality Incentives Program.

Experience in the field. Considerable experience in modernizing and upgrading diesel engines has been gained over the last 8 to 10 years in several key sectors of equipment. High profile diesel emissions reductions projects, such as the retrofit of construction equipment at Connecticut’s Q-Bridge Construction Project and Massachusetts’ Big Dig, have encouraged efforts in other states. Several large-scale diesel engine emissions reduction demonstration programs currently being completed are proving the effectiveness of these emissions control mechanisms.

To educate transportation planners, air quality officials and other leaders about the value of diesel retrofit programs and to assist in getting started with your own program, DTF has designed a comprehensive Clean Diesel Retrofit Tool Kit. This tool kit provides examples of retrofit success stories for a variety of equipment types and vehicles, and it also provides helpful information for developing, funding and implementing retrofit projects in your community. By providing this resource to practitioners, the Diesel Technology Forum hopes to assist environmental and transportation decision makers as they look for effective strategies to clean the air and maximize return on their investment.