Agencies, including the U.S. Coast Guard, Pennsylvania State Police, SEPTA Police, PennDOT and Vision Zero, said they are concerned about impaired and aggressive driving as holiday crowds grow.
Pennsylvania State Trooper Jessica Tobin of Troop K said crashes are never part of anyone's plans.
"No one wakes up in the morning and says, 'You know what? It's a great day to get into a crash,'" she said.
Officials pointed to last year's data from Philadelphia as a warning.
"Over 4th of July weekend, there were five fatalities," said Marco Gorini of Vision Zero.
Advocates stressed that anyone drinking should avoid driving entirely.
"Make the commitment that if you drink, you do not drive. Not after the cookout, not after the fireworks, not that night," said Lana Harshaw, executive director of the Bicycle Coalition.
Safety concerns extend to waterways as well. Sun exposure combined with alcohol or drug use can create dangerous conditions on the water.
"Especially when emergencies happen out in the water, things can turn south pretty fast," said Lt. Tyric Burge of the Coast Guard.
Across agencies, the message remained consistent: enjoy the holiday, but do so responsibly. "Be safe, be smart, and may grace, peace and prosperity rest on the city of brotherly love," Harshaw said.
Pennsylvania State Police said troopers will be stationed at hotspot locations and prepared to respond to drivers who are impaired or behaving aggressively.