Five bills, aiming to modify the Pennsylvania Emissions Inspection and Maintenance Program, have passed in the Pennsylvania Senate and are now awaiting Assembly approval.

If Colorado adopts the policies, the manufacturers would be required to make EVs account for about 5 percent of vehicle sales by 2023.

The states working with California make up more than 40 percent of the U.S. passenger vehicle market.

Colorado state officials said Tuesday that negotiations with automakers on making more electric-vehicle models available, have come to a halt.