Connecticut Clean Air Construction Initiative

Air quality has a direct effect on human health and the environment. To help improve air quality in Greater New Haven, the Connecticut Department of Transportation (CTDOT) is implementing new methods for reducing emissions during the I-95 New Haven Harbor Crossing (NHHC) Corridor Improvement Program.


During construction on the I-95 NHHC Corridor Improvement Program, equipment used on highway contracts will be part of a pilot emissions reduction program for the State of Connecticut. Several factors make the area and timing ideal for this initiative:

  • Construction takes place along a densely-populated corridor. Reduced chemical and particulate emissions will benefit area residents and visitors, as well as laborers working near diesel engines.
  • Construction will span approximately 12 years. The emissions-reduction initiative will reduce the impact on air quality that would otherwise be associated with such a large-scale, long-term construction project.
  • One of the nation's first emissions reduction programs was operated successfully on Boston's "Big Dig." CTDOT was encouraged by Boston’s results and eager to implement a similar program in Connecticut.


CTDOT is requiring all contractors and sub-contractors to take part in the Connecticut Clean Air Construction Initiative.

In summary, the following contractor requirements apply:

  • Emission control devices (such as oxidation catalysts) and/or clean fuels are required for:
    - Diesel-powered construction equipment, with
    - Engine horsepower (HP) ratings of 60 HP and above, that are
    - On the project or assigned to the contract in excess of 30 days.
  • Truck staging zones will be established for diesel-powered vehicles waiting to load or unload materials. The zones will be located where diesel emissions will have the least impact on abutters and the general public.
  • Idling is limited to three minutes for delivery and dump trucks and other diesel-powered equipment (with some exceptions).
  • All work will be conducted to ensure that no harmful effects are caused to adjacent sensitive receptors, such as schools, hospitals, and elderly housing.
  • Diesel-powered engines will be located away from fresh air intakes, air conditioners, and windows.

Initial and monthly reporting by contractors will ensure the proper implementation of the Connecticut Clean Air Construction Initiative. Non-compliance will be enforced with a 24-hour notice to the contractor to improve a vehicle or remove it from a project.

To introduce this new program to area contractors, three informational meetings regarding clean fuels and equipment retrofitting were conducted in August and September, 2001. The sessions were attended by clean fuel vendors and equipment manufacturers who addressed concerns about equipment maintenance and warranties.


The cost of retrofitting equipment or using clean fuels is included in the general cost of the contract, as bid by each contractor. Whereas a contractor who owns equipment may be more likely to install the retrofit apparatus, one who rents equipment may opt to use clean fuels.

Equipment Maintenance and Warranties

On I-95 NHHC Corridor Improvement Program projects, no adverse operational problems or additional maintenance costs have been reported for construction equipment retrofitted with oxidation catalysts. With proper installation, and as long as a system is not stressed beyond its design limitations, equipment warranties are not affected by installation of retrofit products.


EPA has identified emission control standards that will reduce emissions from diesel construction equipment. With the Connecticut Clean Air Construction Initiative, immediate air quality benefits will be realized through the use of emission control devices and clean fuels on existing construction equipment. Long-term air quality benefits will be realized as new construction equipment is purchased and put into use. Because existing construction equipment can operate for more than 30 years, it may be 30 or more years before the full benefits of EPA's standards are realized.

Estimates for reduced emissions during the I-95 NHHC Corridor Improvement Program are 20 tons/year for carbon monoxide and 2 tons/year for fine particulate matter (with clean fuels or oxidation catalysts) and 8 tons/year for hydrocarbons (with oxidation catalysts only).

With the combination of monthly reports from the contractors and periodic site inspections the Connecticut Clean Air Construction Initiative has retrofitted over one hundred pieces of non-road construction equipment with oxidation catalysts. For more information on the Connecticut Clean Air Construction Initiative please contact:

James Kocaba
Connecticut Department of Transportation
PO Box 317546
Newington, CT 06131
860 594 2082

Looking Forward

With good maintenance, heavy machinery with diesel engines can operate for more than 20 years. Retrofitting an engine will cut the lifetime emissions from that engine to a small percentage of what it is today. The EPA, CTDOT, and other local agencies support these measures in their dedication to improving the air quality in the State of Connecticut.

For more information on construction air quality, please refer to the following links and papers:

This program was developed through collaboration between:

Up-to-date Program Information

For the latest on the Program’s progress check this website often or call the Program Public Information Office at 1-203-785-1996. For information on commuting alternatives, visit or call 1-800-ALL-RIDE.

For more information on construction air quality, please refer to the following links and papers: