LIST OF TABLES

ES-1. High priority research issues

ES-2 Prioritized research issues categorized within research topic areas

1. Research gaps identified during the transportation and particulate matter literature assessment

2. Participant votes from FHWA workshop, topics discussed by all participants

3. Participant votes from FHWA workshop, new topics identified during small-group forums.

4. Prioritized research issues categorized within research topic areas

5. Priority and timeframe for medium- and high-priority research topics

6. High priority research issues

7. Medium-priority research issues

8. Low priority research issues