John Latvanas figured it was a fluke when he found the first Baltimore City parking ticket on his truck in mid-December.

He and his son, Jason, who run a pallet-recycling business, had been parking overnight on Southwestern Boulevard for nearly 15 years and never had a problem. When they got a second ticket three weeks later, they started parking a quarter-mile down the road, an area they thought was over the Baltimore County line and out of reach of city enforcement.

But the city parking tickets didn't cease. Over the course of three months, the Latvanases and Bevon Wright, another trucker who parks his vehicle there, said they received nearly a dozen tickets at $252 apiece.

"It adds up pretty quick," John Latvanas said.

In the science of land surveys, the understanding of where a border lies can be inexact. While both the city and county say the border intersects the 3900 block of Southwestern Blvd. — where the truck owners had been parking — a lieutenant with the city's Parking Authority concedes that the exact location of the line isn't clear.

The city has been more aggressive in recent months about overnight parking violations, resurrecting in October the enforcement team that tickets from 10 p.m. to 6 a.m. The overnight patrols are expected to provide a slight bump in parking fine revenue for the city, which collected about $13.5 million in fines last year. In all, Baltimore's 78 parking enforcement agents handed out 309,500 tickets in fiscal year 2013.

Ticketing for the violation the truckers face — a 20,000-pound commercial vehicle parked overnight in a residential area — increased to 247 citations over the past four months, almost double compared to the same time last year. 

The Latvanases and Wright called and wrote the city several times to argue that the trucks were parked in Baltimore County and couldn't be ticketed. Wright, 54, said he spent 45 minutes on hold one day waiting to speak with someone about it. John Latvanas, 63, said he had a heated exchange with one city parking official who hung up on him. Some of their letters received responses saying the cases would need to be resolved in court.

The frustrated truckers said they're not the only ones who think their coveted parking spots are in the county.

Wright said he was parked in his usual spot in February when a car crashed about 100 feet away from his truck. He called 911, and a dispatcher sent Baltimore County — not city — police to the scene.

When the Latvanases saw meter maids handing out tickets another night last month, they called 911, and county police responded then, too. They said the officer told them he couldn't do anything about it, and they'd need to go to court.

During one of the winter's snowstorms, Wright's truck was buried in a snow drift on the side of the road. When a city plow came down the road to turn around, Wright waved down the driver and asked if he could plow him out.

"Can't do it," he said the driver replied. "That's in the county."

"How can they ticket me here but they can't plow me out?" he asked.

City and the county officials said they had never heard of any such issues with ticketing around their borders.

After months of calls from the truckers and a reporter's inquiry, the city sent Lt. William Christian, one of several administrators who oversee the overnight parking enforcement officers, to examine the scene to the west of downtown.

The city said the line is at 3944 Southwestern Blvd. But that's approximate; there is no business or residence at 3944. A wooded area spans most of the 3900 block, which a Baltimore County spokeswoman said is divided by the boundary line. The county declined to send an official to the scene, citing limited resources.

The city's lieutenant went out twice and concluded that the exact location of the line wasn't clear. Christian said he originally thought the city's boundary extended farther west down the block but then noticed a signpost nearer to the middle of the block with both city and county signs on it.

One of the signs along the two-lane road near its intersection with Wilkens Avenue reads: "No Parking of Detached Trailer," which perplexed both the truckers and the lieutenant, because it seemed to imply that attached trailers are acceptable.

Upon examination, the tickets, too, were ambiguous.