Before the sun rises, students in uniform walk the Tenderloin’s dark streets on their way to school.

They’re headed to De Marillac Academy, a free private school for children of low-income families in the Tenderloin and SoMa, that has worked out an agreement with the neighborhood’s drug dealers. They take a break during the children’s morning walk and when school is dismissed. But the ill-lit city blocks remain a safety concern for students and residents.

To help with that, the San Francisco Public Utilities Commission plans to start installing 100 streetlights in the neighborhood’s darkest corridors this year. An unsatisfactory bid for the $4.2 million project has pushed back the project’s timeline, but officials say the new lights will be up by spring 2018. Neighbors and those who plan to work at the new California Pacific Medical Center on Van Ness Avenue are pleased with the project, but wish it had been done years ago.

“It will prevent community violence, because dark corners, blocks and streets have a tendency to be places of crime,” said De Marillac Academy Vice President Michael Anderer. “It’s critical to be able to do this in a neighborhood like the Tenderloin. I only wish it was able to happen sooner and quicker than what it has.”

The $4.2 million project will replace traditional cobra head streetlights, commonly seen in residential areas, with decorative twin teardrop poles like the ones illuminating the streets near City Hall. The 22-foot-high poles will be installed on the north and south sides of Jones, Leavenworth, Hyde and Larkin streets between McAllister and O’Farrell streets, and also on Eddy Street between Larkin and Mason streets.

“This is a complete teardown and rebuild,” said Barbara Hale, assistant general manager for power for the PUC. “We haven’t done much of it historically because we haven’t had the dedicated funding. This opportunity won’t just improve lights. It’s going to give a different look and feel to the streets. The Tenderloin is going to get a spiffing up.”

The project was funded by the PUC and a community benefit grant given to the city by the new medical center that seeks to beautify and improve safety in the Tenderloin. The lights — outfitted with LED bulbs — will emit less stray light and consume less energy. The new lights will be brighter than the current sodium bulbs.

A similar project was completed in 2015 on 10 blocks of Guerrero Street from Market Street to San Jose Avenue in the Mission. The new lights will cover nearly 25 blocks in a high-crime area of San Francisco.

Studies have been unable to confirm a link between streetlights and crime rates. A 2011 study of London that followed street illumination and crime over a 14-year period showed no correlation between increased lighting and decreased crime. But city officials say it will make the area feel safer for pedestrians.

“I am so excited that a project which neighborhood residents have worked on for years is finally happening and we can light up the heart of the city,” said Supervisor Jane Kim, whose district includes the Tenderloin. “Most streetlights here are designed for cars, not pedestrians, so these new lights will mean that residents and workers who walk through the Tenderloin will literally have safer streets.”

The PUC plans to approve a new bid for the project as soon as this month. The powder-blue painted poles could be in place as soon as May 2018, said streetlights project manager Mary Tienken.

“As opposed to utilitarian poles, they will be more decorated and bring color and light to the streetscape,” Tienken said. “There’s a concerted effort to make the Tenderloin a destination. It’s one of San Francisco’s most diverse and unique neighborhoods. This is important for the patients, workers, employees, students and neighbors who walk on the neighborhood’s sidewalks every day.”

De Marillac’s Anderer said it’s part of a push within the neighborhood to implement community safety by environmental design — everything from installing more windows on the first floor of buildings to having more streetlights. It will make students feel safer, he said.

“Safety has as much to do with perception of safety as much as the reality of whether that neighborhood is safe,” he said. “The lights will help change people’s perceptions. You are less likely to stand in the light and sell drugs right there because someone can see you. We have been really looking forward to the new lighting coming in.”

Lizzie Johnson is a San Francisco Chronicle staff writer. Email: ljohnson@sfchronicle.com Twitter: @LizzieJohnsonnn