Commercial vehicle crashes were relatively rare in the program study area, therefore, safety benefits were estimated using a crash avoidance probability model. The model used inspection selection performance data derived from field testing in order to quantify crash avoidance benefits. Inspection performance data were collected from two sites in Connecticut. The results of limited field testing indicated that Inspection Selection Systems (ISS) used in combination with manual inspection procedures increased OOS order rates by two percent. This inspection performance data was input into the crash avoidance probability model and the results were extrapolated to estimate the number of crashes that would have been avoided if ISS were deployed nationwide.

The benefits extrapolated were dependent on variables such as the accident rate for large trucks, the rate at which out-of-service (OOS) orders were issued, and the probability that OOS conditions would influence crashes. These variables were defined based on historical data records in Connecticut.

The model predicted safety impacts for a number of different potential deployment scenarios that weighted "direct" and "indirect" benefits of CVISN. The "direct" scenario increased the rate of OOS orders if motor carrier targeting was improved. The "indirect" scenario improved motor carrier safety compliance if motor carrier perception of strict enforcement was improved.

FINDINGS

The following results were presented in the report; however, the author indicated the results were highly uncertain since the literature-derived crash causation probabilities data input into the crash avoidance model were not well supported.

• The "direct" model indicated that ISS used in combination with manual inspection methods would result in 84 fewer commercial vehicle crashes each year if the two percent improvement seen in Connecticut could be experienced nationwide.
• The "indirect" model calculated crash reduction benefits based on an arbitrary increase in the motor carrier safety compliance rate. For example, if there was a 10 percent increase in the compliance rate, then 8,755 crashes would be avoided each year nationwide, which, compared to the baseline scenario, corresponds to a CVISN benefit of 4,332 fewer crashes.

BENEFIT-TO-COSTS ANALYSIS

In addition to the safety analysis, the report summarized the nationwide benefits and costs of electronic credentialing and roadside enforcement by evaluating different levels of deployment and system effectiveness over a 25 year period.

Three different scenarios of roadside enforcement were modeled.

• No screening,
• Screening with no change in compliance.
• Screening with improved compliance.

Two different scenarios of electronic credentialing were modeled.

• VISTA (Vehicle Information System for Tax Apportionment to coordinate IRP data between state credentialing administrators and the state’s registration database).
• No VISTA.

The analysis considered start-up costs, operating costs, and crash avoidance over the expected lifetime of the technology. The future costs and benefits were compared to 1999 dollars using a discount rate of 7 percent.

Scenario	Benefits ($millions)	Costs ($millions)	Benefit-to-Cost Ratio
No electronic screening; ASPEN only (electronic recording)	69	112	0.62
Electronic screening with no change in safety violation rates	5,301	2,636	2.0
Electronic screening with 25% reduction in safety violation rates	12,995	2,601	5.0
Electronic screening with 10% reduction in safety violation rates	8,379	2,622	3.2
Electronic credentialing in states without VISTA	558	45	12.5
Electronic Credentialing in states with VISTA	339	8	40.4

Benefit-to-cost ratios ranged from 0.62 (not economically justified for a minimal deployment of roadside enforcement) to approximately 40 (highly beneficial for full deployment of electronic credentialing). The author noted these results were highly dependent on the level of deployment, integration, and cooperation between states.