Philadelphia’s traffic congestion was bad before the pandemic. It could get worse.

Megan Smirti Ryerson, associate dean for research at the University of Pennsylvania Stuart Weitzman School of Design, is concerned about those who once chose SEPTA or PATCO over other options such as a private car, but now perceive public transportation as too risky.

If too many people switch to cars, “then SEPTA struggles to provide transportation for everyone, but particularly for those who need it,” she said.

To add to the challenge, troves of past data that transportation planners typically lean on to make future forecasts are essentially irrelevant. This period in history is not “a blip,” she said, but should be considered “an inflection point.”

“All of our planning is based on historical data, and what does historical data mean?” she said. “Just think about your own travel patterns before and after.”