(CHICAGO) Drivers who want an express trip down the Eisenhower Expy. will have to join a carpool or pay a toll, according to the latest plans to expand and improve Chicago’s oldest and second busiest stretch of highway.

State transportation officials have unveiled a “High-Occupancy Toll” lane, in which drivers would have an average speed of 45 miles per hour — light speed compared to the current pace of traffic on the Ike (Interstate 290) during peak times, the Chicago Sun-Times is reporting.

The $2.7 billion plan, which is not likely to see construction begin before 2020, also would add a lane in each direction between the key bottleneck span of I-290, between Mannheim Road and Austin Boulevard.

The “HOT” lane is key to providing reliable travel times on often-stalled stretches of the expressway, said Pete Harmet, the engineer heading the Eisenhower project. The lane would be open to cars carrying three or more passengers, buses and those willing to pay tolls that would rise and fall based on rush hours.

Traffic would move 56 percent faster in the HOT lanes and shave 25 percent of travel times in the three standard lanes, Harmet said.

“One of the key points is a reliable trip, a predictable trip,” Harmet said. “Right now, sometimes it can take a long time, and sometimes it can take longer.”

Similar carpool-toll lanes have been installed in California and Florida, where riders either register their cars as carpool vehicles or use a special transponder, like an I-PASS, to assess tolls while driving. Toll revenue would go toward maintenance and improvements on I-290, which has been toll-free since it opened in the 1950s, Harmet said.

Carpool-toll lanes have been successful at relieving congestion, but they are politically volatile proposals, said Joseph Schwieterman, director of the Chaddick Center for Metropolitan Development at DePaul University.

Drivers reflexively dislike the idea of paying tolls, and they hate watching cars zip past them in carpool lanes, Schwieterman said. But they don’t realize that the prospect of paying tolls and the incentive of carpooling reduces the overall number of cars on the road — and speeds up travel for everyone.

“It’s not an easy sell, even though the congestion problems are going to get worse,” Schwieterman said.

The Eisenhower is built in a “trough” in a densely populated area, so it is difficult to see how acquiring more land to expand the expressway could be politically palatable. Solutions that have been suggested, like building a double-decker highway, are costly and won’t necessarily alleviate long-term travel concerns. Reducing the number of cars on the expressway is likely the best option, Schwieterman said.

“It amazes me that people are willing to accept a dysfunctional Eisenhower, with no real plan to improve it,” he said.

The IDOT plan also would move left-side exits at Austin and Harlem that further slow traffic. It also includes an extension of the Blue Line’s Forest Park spur to Mannheim.

IDOT will release a draft environmental impact report on Dec. 30, and will submit a final draft sometime after a 45-day period for public comments and a pair of public hearings. A combination of state and federal funding would pay the cost of the $2.7 billion project, the largest on the expressway since massive renovations to the Hillside corridor in the early 2000s.