Demonstrators are planning to march down the northbound ramp of the Dan Ryan at 79th and State at 10 a.m. Saturday, hoping to highlight the problem of gun violence. Though Illinois State Police officials have threatened them with arrest, the Rev. Michael Pfleger and fellow protesters still plan on attempting to shut down the expressway.

Here’s what you need to know.

Why shut down the expressway?

The protesters plan to shut down the northbound lanes of the expressway between 79th and 67th streets between 10 a.m. to around noon Saturday.

Protesters want officials and others to help work to fight the gun violence that largely affects the South and West sides. Disrupting the flow of traffic shows lawmakers they’re serious about getting change, they say.

Protesters want resources for their communities, “national common-sense gun laws, jobs, excellent schools and economic development.”

Pfleger has said local lawyers have volunteered to observe and provide free legal assistance if there are any arrests.

RELATED: Despite police warning, Rahm Emanuel says let Pfleger’s marchers onto Dan Ryan

The route for Saturday’s attempted Dan Ryan shutdown | Graphic by Tanveer Ali/Sun-Times

Key players

The Dan Ryan march is led by Pfleger and his church, St. Sabina, in collaboration with Chicago Strong, Gather Activism and March for Our Lives Chicago.

Pfleger and St. Sabina have a long history of peace marches as a way of drawing attention to violence. Earlier this year he asked for school walkouts following the Marjory Stoneman Douglas High School shooting in Florida. In 2016, Pfleger organized the Magnificent Mile March as a way of remembering the 770 murder victims in Chicago that year.

March for our Lives Chicago and Chicago Strong are a coalition of students who are looking for a solution to end gun violence. The groups recently partnered with St. Sabina for the annual end-of-the-year anti-violence rally.

Police plead with the Rev. Pfleger

The St. Sabina Church said state police officials warned that they would arrest anyone who marches onto the Dan Ryan in a hand-delivered letter.

CPD has said it will not participate in arresting peaceful protesters, but will help with crowd control and traffic.

ISP Director Leo Schmitz said he believes in the protesters’ message, but said marching along an expressway is a dangerous.

“This call to protest on the Dan Ryan, however well-intentioned, should be considered reckless and must be strongly discouraged. The potential danger and threat to life are just too great to allow,” he said.

First Deputy Supt. Anthony Riccio also said he sympathizes with the activists, but said diverting resources away from violent-plagued areas will bring more violence.

“We may need up to 200 — maybe even more than 200 — police officers to ensure the safety of these marches,” he said.

Pfleger is not buying the idea of losing resources for this cause.

“We close down streets all the time — for festivals, for mass rallies, for Taste of Chicago, for the president coming in town. We closed down the Dan Ryan last week when . . . a girl stepped in front of an L. This is not the first time they’ve had to close down a major artery,” he said.

Not the first time expressways were disrupted

This is not the first time protesters attempted to shut down the Dan Ryan. In July 2016, about 150 organizers marched against police brutality following the killings of Alton Sterling in Louisiana, and Philando Castile in Minnesota.

In November 2016, protesters briefly closed down Lake Shore Drive from Jackson to Chicago Avenue in the wake of President Donald Trump’s election.

Two years earlier, Lake Shore Drive was temporarily shut down by protesters after a grand jury decided not to indict police officer Darren Wilson in the shooting death of Michael Brown in Ferguson, Missouri.