With a profound sense of patriotism and a sea of red socks to prove it, up to 40,000 runners will participate Sunday in the 34th annual Broad Street Run.

Less than a month after the Boston Marathon bombings, Philadelphia's signature foot race, sponsored by Independence Blue Cross, also will be marked by heightened security and a sense of apprehension.

Most runners interviewed said they would not be deterred by terror, and many planned to wear red socks - trademark of the Boston baseball team - as a symbol of their support.

But some said their families won't be waving along the route or waiting at the finish.

"I've already told my parents that if they do still decide to come cheer me on, that they do so in the middle of the course. I don't want them anywhere near the start or finish lines," said Janine Guerra, who will be running in red socks. "In a way, I'm a little disappointed, because I was really looking forward to having my family waiting for me at the finish."

The race has taken on added resonance this year.

"I am definitely glad that the city has decided to proceed with the race," said Sarah Kaufmann of Philadelphia. "By running without fear, we are showing the terrorists that they have not won and will never win. We are a strong country that stands by its citizens and does not back down."

Coming from Harveys Lake, near Scranton, to run with family and friends, Kevin Moran said, "Everybody is in, without hesitation. First beer postrace: Sam Adams Boston Lager."

Chris Oteri, 28, running his first Broad Street after losing 100 pounds, will pay tribute by wearing red socks and writing "#RunForBoston" on his shoes. "The attack felt personal," he said, "and I will not give up on a sport that has given me so much."

At 25 weeks pregnant, Janet Lewis conceded she will be "running much slower," but "won't be scared off or dissuaded by the events in Boston."

Nancy Curry's husband and 11-week-old son, Silas, will wait for her at the finish. "I am incredibly nervous about my family coming out," she said. "I imagine a lot of runners are. However, I think it's important to continue to live our lives and not allow fear to dictate our choices."

Not everyone feels that way.

Dan Worstall, 49, of Delran, said, "For one of the few times in my racing career, my wife will not be in attendance. I wish that she felt differently."

Lindsay C. Miller of Downingtown won't let her family stand near the finish line. "I told my mom I'll come find her," she said. "My dad and I will be wearing red socks as well as painting a blue and yellow 'B' on our arm in memory of the lives lost."

Jason Anhorn acknowledged being nervous but signed up to run in honor of his father, a cancer victim. "Fear subsides when I remember why I am running," he said, "it's more than just for me."

Jeff Jenkins, a first-timer, said, "I will pay tribute to the Boston victims by running in my 2004 American League champions Boston Red Sox shirt."

"It would be a lie to say I haven't thought about the bombings quite a bit and felt hesitant to do Broad Street because of them," said Katherine E. Bisanz. "However, in the end, I believe that this will only perpetuate the destructive culture of fear that already exists in this country, and I want to be a part of uprooting that fear culture."

While there has been no specific threat, the city has been put on heightened alert, and runners and spectators can expect to see a strong presence of police officers on patrol throughout the 10-mile route. Mayor Nutter said police will also employ hidden security measures.

The U.S. Postal Service will lock 71 mailboxes along Broad Street beginning at 7 p.m. Saturday and unlock them beginning at 4 p.m. Sunday.

Nutter has discouraged backpacks among spectators along the course. Packs will be subject to search. Bags of all types, including coolers, will not be allowed at the Navy Yard, where the race concludes.

Runners will each get a clear plastic bag to stow gear, and it will be bused to the finish. The city has also added a cell tower to improve service at the Navy Yard.

Runners and spectators can sign up for emergency text alerts at www.readynotifypa.org.

With thousands of runners taking the Broad Street subway to the start, SEPTA has heightened security and increased service. Trains will run every 10 minutes from the AT&T station, near the finish line, from 5:35 to 8:30 a.m.

Trains will only stop at the Walnut-Locust and City Hall stations en route to the Olney Transportation Center, a few blocks from the start. Runners can take the Broad Street Line to the start free by wearing their race bib.

Dozens of bus routes, however, will face detours during the race due to road closures. Detours will be in place by 8 a.m.

"We're painting the city red to show our support," said Stephanie Berger. "I am proud to be an American and will show my pride, loyalty, and love for this country any way I can."

Inquirer staff writers Sulaiman Abdur-Rahman and Paul Nussbaum contributed to this article.