Charles Stewart, a Massachusetts Institute of Technology professor, presented the survey at the commission's final public hearing Tuesday and said long lines are problematic.
"Long lines keep cropping up where there are a lot of people, and for the larger jurisdictions this is clearly an issue," Stewart said.
The commission collected data from more than 3,000 jurisdictions and found that larger jurisdictions tended to have longer lines. The commission also found that poll workers did not receive enough training prior to election day, according to the Huffington Post.
The commission will issue a final report in January with recommendations on how to improve voting in the country.