On Saturday, cars were allowed over the bridge in the northbound lanes beginning about 3:15 p.m., after multiple safety tests were conducted, DelDot spokesman Geoff Sundstrom said.
The $45 million project to permanently realign and repair the bridge - paid for with emergency funds from the Federal Highway Administration - will continue through the end of the year.
Delaware Secretary of Transportation Shailen Bhatt said the bridge was "never in danger of falling," but was unsafe for cars to drive across until the initial repairs were made.
"Our folks have been working around the clock to get this done for the last three months," he said.
Bhatt said reopening the bridge would help clear traffic coming from Delaware's beaches Sunday and on Labor Day weekend.
Both northbound and southbound lanes have been realigned, and crews have installed temporary steel towers, which will be replaced by concrete and steel support piers, Sundstrom said.
"The final repair builds on top of the work we have already done," he said.
The closure had snarled traffic on I-95 for nearly three months.
"We had to route traffic through downtown Wilmington to some degree, and then through-traffic was diverted entirely onto I-95 throughout the closure," Sundstrom said. "It made it a more constricted road than it otherwise would have been - and unfortunately, any time there was an accident, we didn't have the additional lane capacity to keep traffic moving as freely as we would like."
In a statement, Delaware Gov. Jack Markell thanked the public for its patience.
"Fully reopening this vital economic link in Delaware and along the Northeast in less than three months is a testament to the hard work and dedication of so many individuals," he said. "Getting this work done quickly was important, but the safety of the traveling public and the many job-site workers was very important, too."