Rank

Variable

Contribution to Variance

1

Problem vehicle identification rate of light-duty trucks (IdenRate)

58.4%

2

Problem vehicle as percent of total PM₁₀ emission of light-duty trucks

10.0%

3

Problem vehicle identification rate of buses (IdenRate)

6.4%

4

Percent of repair work initially effective of light-duty trucks (GoodRep)

5.5%

5

Problem vehicle identification rate of motorcycles (IdenRate)

3.3%

6

Percent of excess emissions reduced by repairs of light-duty trucks (ExEm)

3.1%

7

Problem vehicle illegal operation rate of light-duty trucks (IllegalVeh)

2.4%

8

Problem vehicle identification rate of city trucks (IdenRate)

1.8%

9

Program participation rate of light-duty trucks (PartiRate)

1.8%

10

Percent of durable repairs of light-duty trucks (DurRep)

1.2%