Take a look at the latest designs for new toll lanes on Interstate 66 and how the changes will impact traffic throughout the area.

WASHINGTON — Under the latest designs for new toll lanes on Interstate 66 outside the Capital Beltway, a Metro power substation would be relocated, much of a jogging and bike trail would be next to the highway, and drivers would see dozens of new bridges, toll gantries and traffic patterns.

The refined designs will serve as the basis of final public hearings next month . Construction work could begin before the end of the year, with the most significant work ramping up along much of the 22-mile corridor between the Beltway and Gainesville, Virginia, in the first half of 2018.

The lanes are scheduled to open in 2022. They will be free for cars with three or more people and an E-ZPass Flex switched to HOV mode, while other vehicles will be charged a variable toll that rises or falls based on the amount of traffic in the toll lanes.

The multicolored final designs can be complicated to read, with curling purple aerial structures, dashed lines for potential noise walls, red toll lanes, yellow general purpose lanes and orange ramps next to thin red lines that mark the home and business property that will be taken or purchased by the project.

Among the details in the designs:

Express Lanes users will be able to enter or exit the toll lanes at Monument Drive in any direction at all times of day. The designs add new ramps. There would still be no access to Monument Drive from the regular lanes.

A significant redesign of the I-66/Chain Bridge Road (VA-123) interchange, including a complete rebuild of Chain Bridge Road through the interchange.

The project will pay to move a Metro power substation near the Dunn Loring Metro station that the private companies designing, building and operating the two toll lanes in each direction next to three regular I-66 lanes had initially suggested building a ramp over as a way to save money. A vocal group of neighbors opposed that, and Virginia Gov. Terry McAuliffe told WTOP in April that the designs would be reworked. Instead, a shorter ramp between the regular eastbound lanes and the toll lanes will provide access.

Recently, proponents of a jogging and bike path that is part of the project expressed concerns about a significant portion of the route running directly next to the highway. The final design proposals would put a majority of the trail being built directly as part of the project next to the highway, either inside the sound wall or next to the highway in an area where no new sound wall is proposed. In Prince William County, only three small segments of the trail are being built as part of the project. Each of those segments runs along a road other than I-66.

Other highlights (from east to west):

A new park and ride off Balls Ford Road near Manassas National Battlefield would have an entrance and exit only to and from the express lanes to and from the east. Like other park and ride structures planned as part of the project, it would include a bus area, kiss and ride, and slugging area. The park and ride would be expanded by 2040.

Past the battlefield, a new separated exit for Sudley Road (234) and flyover ramps allowing drivers in the regular lanes to move into the express lanes toward the Beltway or out of the regular lanes toward Gainesville, a shift for the rest area pavement, and new bridges for I-66 and Bull Run Drive will carry traffic.

In Centreville, drivers in the express lanes will not have a direct exit to U.S. 29.

Major changes for Route 28 are a key part of the project. The new interchange, to be surrounded by sound walls, includes crossings for the bike and jogging trail, at least 10 new bridges for highway traffic, and changes on Route 28 that would connect Walney Road and Braddock Road over Route 28, add a new service road out of E.C. Lawrence Park to avoid the current turn onto or off 28, and there will be a new extension of Poplar Tree Road across Route 28 to connect to Stonecroft Boulevard behind Sully Station Shopping Center.

This is the design plan for the I-66-Route 28 interchange.

At Stringfellow Road, drivers in the toll lanes headed eastbound will have an option to move to the regular lanes. Only drivers in the toll lanes headed westbound will have an option to exit at Stringfellow Road, and the only entrance will be for drivers headed eastbound in the toll lanes. That entrance and exit are scheduled to be open around the clock. I-66 will cross over Stringfellow Road on new bridges, which will include extended eastbound exit lanes for drivers going to or from the Fairfax County Parkway. Additional extended entrance and exit lanes are planned around U.S. 50.

As noted above, the Monument Drive exit would expand to allow entrance and exit in both directions (to the toll lanes only).

At the Route 50 interchange, not all drivers would have direct access to the toll lanes or from the toll lanes to Route 50. The designs call for adding an entrance from westbound 50 to the westbound toll lanes and an exit from the eastbound toll lanes to eastbound 50. Drivers in the regular lanes would continue to have the option to exit or enter in any direction.

The interchange with VA-123/Chain Bridge Road would be revamped to reduce the number of curving ramps and add traffic lights at several I-66 exits. Drivers will be able to exit or enter the toll lanes in either direction. The interchange includes trail connection crossings and a new bridge to carry VA-123.

A series of projects around the Vienna Metro station would revamp traffic patterns there. To and from the west, the toll lanes will connect to a new Vaden Drive bridge to provide bus and carpool access. On the west side of the station, the I-66 and Nutley Street interchange will be completely rebuilt into what is known as a diverging diamond setup. From Nutley Street, drivers will have direct access to only the regular lanes.

As noted above, in the Dunn Loring area, the designs now propose relocating a Metro power substation to the south side of I-66 just to the west of the development at the station. Express Mobility Partners did not immediately respond to a request for comment on whether they or the state would bear the cost of the change. Also in that area, Gallows Road would be realigned to the east, away from Stenwood Elementary School.

At the Capital Beltway, the existing maze of on and off ramps is set to get even more complex. A series of new bridges, entrances and exits, and stormwater management ponds will be constructed largely over and around the existing roadways. Drivers in both the toll and regular lanes will have exits or entrances to and from the regular lanes on the Beltway, I-66 and the toll lanes on each road.

The tolls on I-66 inside the Beltway are separate but related to this project. Those rush-hour only tolls begin for solo drivers in December.