Virginia Gov. Ralph Northam (D) joined Republican lawmakers Tuesday in announcing a proposal to toll Interstate 81 to generate money to pay for $2.2 billion worth of improvements needed along the corridor that serves as main street for western Virginia and a major economic artery for the state.

The plan, to be introduced in the Virginia General Assembly session that starts Wednesday, would establish tolls as a source of revenue for “critical improvements” identified in a state study of the route that stretches 325 miles between the Tennessee and West Virginia borders and suffers from major safety and reliability problems.

With the proposal, Northam and lawmakers representing the western part of the state are choosing to push a toll system over establishing a regional gas tax to pay for the I-81 improvements and in doing so declaring broader support for expanding the state’s toll network. The state in recent years has significantly increased its toll network, establishing systems along several major highways, including Interstates 95, 495, 66 and 64.

The proposed legislation would establish limits on toll rates and give some road users, including commuters and small trucks, the option to purchase an annual pass that would allow unlimited use of the road, Northam said. The tolls could generate $145 million in the first year and $166 million annually by the fifth year, according to a state report unveiled last month.

The plan assumes six gantries in each direction along the corridor, and tolls would vary based on time of travel (daytime vs. nighttime) and type of vehicle (trucks vs. cars). The annual pass would cost a projected $30, and drivers would travel at least 40 miles between gantries.

The proposal comes with bipartisan support from members of the General Assembly representing the corridor, according to the governor’s office.

Northam said all revenue collected would be used in the I-81 corridor for projects such as widening the highway, curb improvements and adding auxiliary lanes. Operational improvements include the expansion of traffic cameras and message boards, more safety service patrols, improvements to parallel roads, enhancement to truck parking and contracting with an emergency patrol service to clear crashes faster and reduce impacts on traffic.

"It’s time we take decisive action to enhance the safety and improve the reliability of this key corridor,” Northam said in announcing the proposal, which he said would be introduced by state Sens. Mark D. Obenshain (R-Harrisonburg) and Charles W. Carrico Sr. (R-Grayson) and Dels. R. Steven Landes (R-Augusta) and Terry L. Austin (R-Botetourt).

More than one-third of all trucks and nearly 50 percent of the state’s value of goods are carried along the interstate, making the corridor critical to the state’s economy, according to a state report. About 11.7 million trucks move through the corridor each year. It also is a key piece of the freight network for the East Coast.

But the corridor suffers from safety and reliability issues, according to the study, prepared by the consulting firm Kimley Horn. There are more than 2,000 crashes annually along the route, of which 26 percent involve heavy trucks — the highest percentage for any interstate in Virginia, according to the report. The crashes result in significant travel delays on the highway, which has two lanes in each direction for a majority of the corridor.

Although improvements have been made over the years to keep up with growth, the corridor has experienced an increase in traffic that has resulted in degradation of the road’s performance, the report said.

“Travel is anticipated to continue to increase on I-81, with truck traffic growing at a faster pace than passenger vehicle traffic,” the report said, projecting nearly 20 million trucks trips, carrying $750 billion worth of goods annually, by 2040. “Without implementation of an improvement plan, performance conditions along the corridor are expected to continue to degrade as traffic continues to grow.”

State lawmakers said the proposal could be the answer to establishing a funding source for improvements that would make the corridor safer and more reliable for all road users, including residents.

“The hard-working citizens in the communities on the I-81 Corridor deserve a viable, long-term solution to the challenges of travel along this route,” Landes said in the governor’s news release. “A focus on key improvements and dedicated funding for the corridor will positively affect those who rely on it every day."