Barrio Logan hasn't had their community plan updated since 1978.

In Barrio Logan, it's hard to know who to call when loud noises disrupt sleep.

"Enforcement is always difficult but the first line of defense would be code enforcement at the City of San Diego," says Mark Steele, chair of the Barrio Logan community planning group.

But what if the neighbors operate a freight train? Within earshot is Naval Base San Diego, subject to federal guidelines rather than local policies. Another neighbor, the Port, isn't subject to San Diego's general plan or noise ordinance. And the community is surrounded by state regulated freeways.

Zoned for industrial uses in the 1930s, the barrio's community plan (circa 1978) allows homes and industry to overlap. A buffer "would reduce noise by increasing the distance" between clashing uses, it notes.

But the plan still hasn't been updated. Shipyards and other industry abut homes; port of San Diego trucks have been caught on prohibited streets; and noise has been a hot topic at community planning sessions.

At a meeting on September 18, Maggie Weber, senior planner for the port of San Diego, presented the Barrio Logan nighttime noise study, the latest effort to aid the small community surrounded by giants. The study was requested by San Diego City councilmember Vivian Moreno.

Earlier this month Moreno requested that the police department present an enforcement plan for the restricted truck routes through Barrio Logan, where dozens of tickets have been issued despite an ordinance passed last December which the port supported – that routes them out of the neighborhood.

For the rest of the year, the port will build a noise profile of the area, drawing on interviews with residents, businesses and industry, as well as online surveys and data from portable monitors. It will span the hours from 10:00 p.m. to 6:00 a.m., focusing on the wee hours between 1:00 and 4:00 a.m.

Who's making the after-hours racket? So many potential sources, Steele says no one can identify a single worst offender.

The study will home in on a range of suspects. Shipyard and maritime operations, interstate freeway traffic, railway activity, on road diesel trucks, construction, downtown activity, and more.

Noise pollution raises the risk of cardiovascular and other health problems, studies show, and is more often found in low income and non white neighborhoods.

Barrio Logan is among the communities the Office of Environmental Health Hazard Assessment and the California Environmental Protection Agency consider “disportionately burdened by multiple sources of pollution."

The noise study isn't a first for Barrio Logan.

In 2011, in preparation for a long-overdue community plan update, a detailed noise study was done that addressed current and future noise to 2030 from transportation and stationary noise sources.

"Traffic noise and railway generate the greatest noise levels," it said. There were 45 blue line trolley trains running overnight on weekdays. "I-5, SR 75, Main Street, Harbor Drive and 28th Street will continue to be the primary traffic noise sources in the area."

Under the currently adopted community plan, things were projected to get a lot worse. Residential permitted land uses would be exposed to noise levels in excess of 75 CNEL (a very high measure of community noise) in areas along Boston Avenue, for example.

The 2013 community plan update would have re-zoned Barrio Logan. A buffer zone would separate homes from industry and shipyards. Parking structures or other buildings would be encouraged. The city council approved the draft, but San Diego voters scrapped the plan.

The next update on the port's nighttime noise study will be discussed at the Barrio Logan community planning group meeting on October 16. Weber says the full study will be available upon completion early next year.

The report will suggest strategies and practices that could be used to curb nighttime noise. The whodunnit might help end it, if the study's recommendations are followed.