Engineers are beginning to fix one of the most daunting intersections in Washington County — a year after it was rebuilt as part of the St. Croix River bridge project.

Nearly 30,000 eastbound vehicles arrive daily at the intersection of Hwy. 36 and Osgood Avenue in Oak Park Heights. But despite a recent reconfiguration aimed at bringing it up to modern standards, many drivers remain perplexed about how to navigate the intersection, particularly where frontage roads converge south of Hwy. 36.

“There’s a lot of confusion at this intersection right now,” said Assistant County Engineer Cory Slagle. “You just see a lot of people hitting their brakes.”

Few intersections in Washington County have been more affected by growth and development than Hwy. 36 and Osgood, which funnels interstate traffic toward the Stillwater Lift Bridge. When the new, four-lane St. Croix River bridge opens a mile away, possibly in 2017, forecasts show traffic through the intersection could increase substantially. Drivers also could establish new traffic patterns as they adjust to new routes.

“Over the years, this was the project that was approved, but it’s not an ideal situation,” Slagle said of the current configuration. “Now we have the opportunity to make the ­situation better.”

Now, motorists trying to cross the four-lane Osgood on the south frontage road sometimes get stranded in the middle as they wait to cross the last two lanes. And traffic backed up at the Hwy. 36 stoplights can block cars from crossing Osgood.

The situation had been much the same at the next intersection farther west — Hwy. 36 and Oakgreen/Greeley — where weaving traffic often resembled a plate of spaghetti. To reduce backups and collisions, the state Department of Transportation moved frontage roads farther from the main intersection as part of the $70.7 million reconstruction of Hwy. 36. The reconstruction, finished a year ago, also included new surfacing and more turn lanes.

While the Osgood and Hwy. 36 intersection “in general is working well,” problems at the south frontage road cause traffic jams at peak times, said Kristin Calliguri, a MnDOT bridge ­project spokeswoman.

Washington County engineers, taking the first step toward addressing the snarl, recently received approval from the County Board to move the south frontage road entrance east of Osgood. By the end of next summer, it will be moved about 500 feet farther south of the main intersection, looping behind a Holiday Stationstore, Slagle said.

That $1 million project eventually will close a reconstructed portion of the south frontage road — also known as County Road 26 — that was recently completed. Despite the new work, traffic problems persist.

“Obviously there’s a big bottleneck there, a lot of things happening for people to make decisions when to signal or not,” said Washington County Commissioner Gary Kriesel, who represents ­Stillwater.

The new bridge — the most visible element of the $670 million transportation project — will connect to new approach highways in Minnesota and Wisconsin. Most of the highway work in Washington County has been completed, but engineers have admitted to some frustration over finding solutions for the Hwy. 36-Osgood intersection.

Terry Zoller, MnDOT’s construction manager on the bridge project, said recently that the agency has reviewed the intersection’s problems “extensively” over the years and even offered incentives to construction companies to find solutions.

“None of the concepts for this intersection were found to be acceptable due to right of way and business impacts,” he wrote to Mayor Mary McComber of Oak Park Heights, who had appealed for help in resolving traffic ­problems.

Upcoming changes to the south frontage road come just months after a frontage road on the north side of Hwy. 36 was moved because of similar traffic snarls.

Once the bridge opens, the county will make improvements to Osgood, which is also County Road 24, and commission a traffic survey to determine new driver habits.

Slagle said it’s better to correct a problem than stick to a design that doesn’t work. The south frontage road that runs west of Osgood will require more study and expense because of the many businesses in that area, he said, but the county will work quickly to fix the east side — the only access to an Oak Park Heights neighborhood near the bridge site.

“It’s important to get it done before the river crossing opens, because traffic will increase,” he said.