Impacts of a Vehicle Inspection and Trip Permit Program on Vehicle Operations and Equity

Principal Investigator:  Jennifer Dill, Ph.D.

Sponsors: TransNOW and Oregon Department of Transportation

Background

Like most states, Oregon has a vehicle inspection program (VIP) to help meet air quality standards. Vehicles in the Portland and Rogue Valley areas must pass the test to get a certificate required to register the vehicle. Owners of vehicles that do not pass the test prior to their registration expiring can obtain a short-term "trip permit." Trip permits provide vehicle owners a legal way to drive their vehicles after failing an emissions test, but before making the repairs to pass the test and renew their registration.

Starting January 1, 2002, the State implemented significant changes to the trip permit system. The State now issues no more than two 21-day permits in a 12-month period to any vehicle. In addition, the new system tracks the permits via a computer database. Previously, a vehicle owner could get a permit for up to 120 days in a 12-month period, and the permit records were not computerized. Therefore, owners could purchase successive permits with little or no chance of being caught. There was a belief that ousing trip permits to avoid registering vehicles when they failed a vehicle emissions test. wners were

Research Objectives

The primary purpose of this research was to assess the impacts of changing the trip permit system, addressing four key questions:

• Was there a change in the number of trip permits issued?

• Has the new system resulted in vehicles getting fixed and passing emissions inspections faster?

• Are more vehicles being repaired to pass emissions inspection and being registered as a result of the new system?

• What is happening to vehicles that do not pass the emissions inspection, even after getting a trip permit?

To answer these questions, we analyzed a variety of data sources, including DEQ and DMV records. Unfortunately, trip permit records prior to 2002 were not tracked. Records were only kept in original paper form in chronological order. Therefore, it would not be possible, for example, to take a DEQ record from 2001 and find out if that vehicle got a trip permit. Nor would it be possible to see how many vehicles obtained more than one permit in 2001. Given this limitation, we attempted to answer the questions by tracing records from various directions and conducting a survey of vehicle owners.

Findings

The change in the trip permit system appears to have significantly reduced abuse of the program. However, not all vehicle owners were necessarily repairing their vehicles, passing the emissions test, and registering their vehicles. Key findings include the following:

• The number of trip permits issued in 2002 was dramatically smaller than in 2001. This finding supports the hypothesis that within the VIP areas people were using successive permits, and that the change in the system reduced such abuse.

• The new trip permit system does not appear to be affecting how quickly vehicles are repaired to pass DEQ inspections.

• There was an increase in the share of vehicles that initially failed a DEQ inspection and eventually passed, an intended effect of the change. However, there was a similar increase in the number and share of vehicles that took multiple tests, failing both the first and last tests.

• More people who obtained trip permits in 2002 and failed a DEQ test (compared to 2001) eventually renewed their registration – one intended effect of the change.

• The vehicle owner survey confirmed that fewer vehicle owners were using trip permits. However, the survey also revealed that some owners of vehicles that failed a test in 2002 registered the vehicle outside of the VIP area, but kept it in a VIP area. While most of these owners claimed to not drive the vehicle, the responses suggest that there is some evasion still occurring.

• We estimate that less than one-half of one-percent of all the registered vehicles subject to VIP each year do not pass a DEQ test and do not renew their registration with DMV. About 15% of these may still be owned by the same person and kept within a VIP area, but without passing a DEQ inspection.

Final Report