Days before the 2020 election, supporters of President Donald J. Trump driving in vehicles festooned with flags as part of a so-called “Trump Train” surrounded a Biden-Harris campaign bus as it sped along a Texas interstate highway.

Images of the impromptu convoy of antagonists were memorable: a large bus decorated like a Biden campaign sign and, all around it, dozens of pickup trucks and sport utility vehicles with pro-Trump banners waving. Photos and videos provided a visual preview of the kinds of political confrontations that would culminate months later with an insurrection at the U.S. Capitol on Jan. 6, 2021.

Now those same images from Interstate 35 will be used as evidence in a federal civil trial that seeks to hold the Trump supporters responsible for assault and political intimidation tactics. Opening arguments begin on Monday.

The plaintiffs in the case include Wendy Davis, a former Texas State Senator, and members of the 2020 Biden presidential campaign, along with the driver of the bus. They have argued that the Trump supporters drove recklessly and dangerously, slowing at times to as little as 15 or 20 miles per hour, and tried to force the bus off the road. They said some of those in the caravan appeared to believe that Kamala Harris, then a U.S. senator and candidate for vice president, might be aboard, though she was not. There was one collision between vehicles, but no one was hurt.

The trial, which was expected to last two or three weeks, comes in the midst of a presidential campaign in which Mr. Trump is again the Republican candidate and Vice President Harris is at the top of the Democratic ticket. Fears of political intimidation and potential violence have only intensified, particularly after the attempted assassination of Mr. Trump at a rally in July.