6. Recommendations for Future Study

6.1 Recommendation 1: Expanded Environmental Impact Assessment

The 1990 Clean Air Act Amendments (CAAA) significantly increased the attention paid to the relationship between transportation modes and emissions. The CAAA imposed National Ambient Air Quality Standards (NAAQS) for critical pollutants, and also established schedules to attain these standards linked to the level of severity and type of pollutant. The CAAA also required that states establish State Implementation Plans (SIPs). The SIPs detail the State Action Plan that would be implemented (including the surrounding region, as required) to achieve the standards.

The 1991 ISTEA established a conformity requirement in support of the CAAA. Under ISTEA, states are required to develop annual Transportation Improvement Programs (TIPs) that conform with the SIP. The intent of these plans is to ensure that a State or region does not implement a transportation program that is contrary to the SIP or has the potential to increase rather then decrease emissions.³³

Under the CAAA, the majority of the northeast and Mid-Atlantic States, as well as the District of Columbia, include metropolitan areas

or counties that are classified as non-attainment areas (i.e., that have not met the NAAQS established through the CAAA). These states have implemented a number of strategies for reducing emissions, including the testing of emissions from on-road mobile sources.³⁴ The Environmental Protection Agency (EPA) has determined that on-road mobile sources

...collectively are the single greatest contributor in this country to carbon monoxide pollution and to ground-level ozone, the major component of smog. In typical polluted cities, vehicles contribute between 35 and 70 percent of ozone-forming emissions and 90 percent or more of carbon monoxide emissions. Ambient concentrations of one or both of these pollutants exceed national air quality standards in virtually every major urban area of the country.³⁵

The environmental analysis conducted for the evaluation demonstrates the potential environmental benefits that can be obtained through the deployment of ITS/CVO technologies and systems. Given this impact, it is recommended that consideration be given to conducting a more comprehensive Environmental Impact Assessment using actual emissions data. If implemented, this test would be conducted by outfitting commercial vehicles (CV) with equipment that measures actual emissions, and then having these CV pass by weigh stations and toll plazas. The test would measure the difference in emissions from a bypass at a weigh station as compared to entering a weigh station and passing through a sorter ramp or the static scale. The test for ETC would be done in a similar manner by capturing the emissions difference from using ETC as compared to stopping at a plaza and paying cash.

It is further recommended that this test be done with several different types of commercial vehicles and CV engines so as to accurately model actual commercial vehicle traffic that passes by a particular facility. The test should also be done at different times of day and night and at different times of the year. The suggested testing protocol would enable measuring the impact of varying traffic flows at different times of day and night, as well as enable the ability to estimate seasonal impacts. The rationale for this recommendation is as follows:

Many states in the I-95 corridor have significant non-attainment areas.
Capturing environmental benefits available from the deployment of ITS/CVO has the potential to expand the stakeholder base supporting these deployments. If the ETC or E-screening deployment can be shown to have an emissions reduction benefit, MPOs, state environmental agencies, and other interest groups may be brought into the stakeholder community - thus expanding the support for obtaining funding and resources from senior management and elected officials.
Capturing environmental impacts also expands the potential for obtaining funding from new sources (for example, CMAQ).
If implemented, it is recommended that the assessment be structured as a 1-year test to enable the complete estimation of environmental impacts with seasonal variations included.

6.2 Recommendation 2: Expanded Safety Study

As indicated previously, the data needed to conduct the Safety Test was not available during the period of performance for the evaluation. It is recommended that consideration be given to conducting the Safety Test when the degree of market penetration has reached the point where statistically valid data can be obtained. As an alternative, consideration may be given to obtaining data from an existing program to conduct the test.

As part of the project literature review, the Evaluation Team reviewed existing studies on commercial vehicle safety to determine if any previous studies had assessed the safety impacts of electronic screening. While many studies have been conducted to analyze the benefit cost ratios and safety improvements of programs like CVISN and the Inspection Selection System (ISS), it was determined that to date, there are no studies of record that assess the correlation between the use of transponders and impacts on commercial vehicle safety.

The Evaluation Team did identify some studies that have examined certain aspects of transponder use and commercial vehicle safety. In the paper titled Benefit-Cost Assessment of the Commercial Vehicle Information Systems and Networks (CVISN) in Maryland,³⁶ safety is considered a benefit and the implementation of transponders a cost. The analysis concludes that the benefits of CVISN outweigh the costs. However, this presents no real information on the correlation between transponders and safety, only that the study team made the assumption that "the accident rate due to commercial vehicles will decrease, assuming that carriers who have transponders can be identified for safety enforcement."³⁷

In the paper titled Maryland Motor Carrier Program Safety Profile of Commercial Motor Carriers Traveling in Maryland at the Perryville Scale House Under the Jurisdiction of the Maryland Transportation Authority Police,³⁸ there is little or no discussion of transponders. The transponders are only referred to in conjunction with the CVISN project, where they are assumed to improve upon the identification process,³⁹ thus implying that the use of transponders helps to identify those vehicles posing a safety risk. However, the paper does not show a significant relationship between transponder use and transportation safety.

Future research is needed to assess the relationship between the presence of transponders and increased safety benefits, hence this particular recommendation. If such research is conducted, the safety test developed for this evaluation represents an excellent resource for the development of any experimental design.

6.3 Recommendation 3: Identification Of Opportunities For Expanding Interoperability

The results of the Efficiency Test indicate that the best way to promote the use of transponders in commercial vehicles is to expand interoperable applications. The economies of scale generated by interoperability offer a strong potential value added service to motor carriers, and it is this added value that will attract industry.

It is recommended that consideration be given to identifying additional opportunities for expanding interoperability. As noted in Section 1 of this report, the Eastern Seaboard is home to some of the more congested regions of the country. As freight movement increases, identifying opportunities to use transponders to assist with congestion mitigation and management at seaports, airports, and intermodal facilities, in addition to applications such as ETC and E-screening, offers one option available to the I-95 Corridor Coalition member states to expand interoperability within the region.

If such a study is conducted, it is further recommended that the scope of the study include the following:

Identify potential interoperable applications and assess the potential market for each particular application.
Identify potential institutional and technical challenges that may impede deployment.
Identify, at a high level, the technical requirements that would need to be addressed.
Identify stakeholder groups who would need to be involved in establishing additional interoperable applications.

³³ Adapted from FHWA Report No. PD-97-051, "Air Quality Impacts of Intercity Freight, Volume I: Guidebook," Section 4.1.
³⁴ On-road mobile source emissions are generated by motor vehicle operations on public roads and highways, including passenger/light duty cars and trucks, motorcycles, and heavy duty vehicles (trucks and buses). Heavy-duty vehicles are subdivided into gasoline- (HDGV) and diesel- (HDDV) powered vehicles. Accessed from EPA Web link: http://www.epa.gov/otaq/invntory/overview/examples.htm.
³⁵ Accessed from EPA Web link: http://www.epa.gov/reg3artd/vehicletran/vehicles/vehicle_emissions_testing.htm.
³⁶ Benefit-Cost Assessment of the Commercial Vehicles Information Systems and Networks (CVISN) in Maryland, page 16 of 98, accessed from: http://www.eng.morgan.edu/~ntc/Final.pdf.
³⁷ Ibid.
³⁸ Maryland Motor Carrier Program Safety Profile of Commercial Motor Carriers Traveling in Maryland at the Perryville Scale House Under the Jurisdiction of the Maryland Transportation Authority Police, page 66 of 72.
³⁹ Ibid.

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