Outside the front door of Jaha Hair Studio, Bonifant Street soon will be narrowed to one lane for about two years. Most of her customers’ street parking will disappear. She and about 20 other small businesses on the block have been warned that they’ll lose water and electricity at times.

“We’re just really, really worried right now,” said ­Peterkin-Bishop, a single parent with two children in college. “For most of us, this is how we work to make a living for our families.”

Dust flying off trucks rumbling past coats the indoor tables, and the bar’s shiny black floor has grown dingy from customers tracking in dirt.

“It’s been a huge inconvenience,” McManus said, “and a huge financial burden.”

Maryland lawmakers are considering whether business owners who will live through four to five years of Purple Line construction should have financial help to make sure they’re still around to enjoy its potential benefits.

One proposal would grant credits toward the business owners’ state property and income taxes for lost revenue. Another would allocate $1 million for grants to help offset losses.

“The entire purpose of the Purple Line is to boost the economy,” said Del. Jheanelle Wilkins (D-Montgomery). “What would it say about the success of it if we were to lose these small immigrant-owned businesses along the way?”

Sen. William C. Smith Jr. (D-Montgomery), who supports both proposals to aid business owners, said he’s particularly concerned about businesses that are already struggling.

“If you’re operating month to month, this type of construction could be devastating,” Smith said. “We know if they can survive construction, they’ll thrive on the other end.”

Most of the 600 businesses potentially affected are in downtown Bethesda and Silver Spring, along New Hampshire Avenue and University Boulevard in Langley Park, and along Kenilworth Avenue and Riggs Road in Riverdale and Hyattsville. The state has no program to compensate them for lost revenue.

The contract for the $5.6 billion public-private partnership to build and operate the line requires the contractor, Purple Line Transit Partners, to provide “open for business” signs and inform owners about expected effects.

Erin Henson, a spokeswoman for the Maryland Department of Transportation, said the agency is “actively working with businesses located near the Purple Line” to address their concerns, including providing signs, parking and access for customers and suppliers.

“Ultimately, one of the goals of the Purple Line is to drive economic development and grow jobs throughout the corridor that all these businesses will benefit from,” Henson said.

Carla Julian, a spokeswoman for the contractor, said that project officials have met with numerous business owners and that construction managers will continue to meet with them to discuss upcoming work in their areas. She said the contractor is using a “case-management approach” to understand each owner’s needs for access and deliveries so it can try to mitigate effects and plan work “in a manner that is in line with being a good neighbor.”

Another spokesman said any dirt in downtown Bethesda is probably coming from a construction site adjacent to the Purple Line work.

“Frankly, we have to be careful because we don’t have the resources to deal with some of these issues, which historically we haven’t,” Rahn said. “I don’t want to make promises to do anything that we at MDOT can’t handle.”

In other regions with recent light-rail projects, business owners say they lost about 20 to 40 percent in revenue because customers avoided the construction zones or grew frustrated trying to reach them amid traffic jams and detours.

Even so, chamber of commerce officials in Charlotte and the Phoenix area said they couldn’t recall any businesses that closed directly because of the construction projects.

In the Phoenix suburb of Tempe, Raveen Arora said revenue at his Indian restaurant and marketplace dropped 12 to 18 percent during light-rail construction a decade ago. He said he knew of 15 or so other businesses that closed or moved, either because they lost too much money or didn’t want to put up with the noise, dust and other hassles.

He said he survived by touting his restaurant’s loyalty to the community and stepping up customer service. Business is good, he said, and many of his customers now use the light-rail line to reach him.

“It was a tough three years — it was nightmarish,” Arora said. “But you open your eyes and the nightmare goes away.”

County officials note that the Purple Line is a state project, but say that preserving local businesses is a top priority. In Montgomery, county officials are converting 300 spaces in a nearby parking garage into short-term meters to offset the 40 on-street parking spots that Bonifant businesses will lose during construction.

In Prince George’s, county officials are asking that businesses receive advance notice of lane closures and have their sidewalks kept open when possible.

Whether the legislative proposals for financial compensation will pass is unclear.

MDOT has declared no position on the tax-credit bill, but said it doesn’t have the staff “to conduct the complex business analysis” it would require. Trying to establish losses “directly caused by a particular construction project,” the agency wrote, “can be near impossible altogether, especially for a state agency charged with providing transportation solutions.”

Comptroller Peter Franchot supports the tax credit, calling it “reasonable assistance” to build a rail line that will be “a critical ingredient to the continued economic and population growth in the region.”

Meantime, restaurant owners say they’re looking into expanding their delivery and catering or offering more specials to draw people in. Peterkin-Bishop said she is advising her salon customers to use a nearby public garage and will offer valet parking for elderly clients who can’t walk that far.

Francisco Escobar, who owns the Ropa Colombiana store on University Avenue in Langley Park, said the Purple Line will be good for the area. But he said he’s bracing to lose more than half his business during construction and worries that his rent will continue to increase as property values around light-rail stations go up.

“Open for business” signs, he said, won’t help pay his rent.

“Why should we take the pain and suffering economically and not anyone else?” Escobar said. “That’s not justice.”