The Philadelphia Parking Authority has grown its workforce and expenses in the last decade through a program that has nothing to do with parking: red-light cameras that snap photos of license plates when drivers ignore traffic signals.

The program has also left a lot of money on the table, almost $19 million in unpaid fines, and the PPA took action only last month to increase collections.

Legislation in Harrisburg would duplicate the effort, putting the PPA in charge of new "speed cameras" placed along Roosevelt Boulevard in Northeast Philadelphia to photograph and fine speeding drivers.

State Rep. John Taylor, a Northeast Philadelphia Republican, proposed the speed camera legislation. In a newsletter to constituents in June, Taylor called the Boulevard "one of the most dangerous roadways in the state," especially for pedestrians crossing wide intersections.

"We must find more resourceful ways to slow drivers down," Taylor wrote.

The legislation, which has 11 co-sponsors, including seven Philadelphia Democrats, sailed through the House Transportation Committee, which Taylor chairs, but has yet to come up for a vote by the full House since leaving committee on May 24.

Taylor on Thursday said his bill would most likely be combined with a Senate bill that would allow speed cameras to be posted in highway work zones across the state, and might not get a vote until the General Assembly returns to Harrisburg after the summer break. There is a history of tension in the state Capitol regarding highway legislation, where roadway safety measures face suspicion as revenue generators in disguise.

"I tried to use a model that sort of stood some tests already," Taylor said of the speed camera bill's resemblance to the red-light camera law. "We definitely can't have any smell of a revenue raiser."

Red-light cameras are designed to prevent crashes in intersections, specifically T-bone collisions that can be catastrophic for the driver hit when another person runs a red light, officials said.

Speed cameras are designed to slow people down throughout a roadway.

"Speeding drivers need more time to slow down," said Juan Martinez, director of strategic initiatives at the New York City Department of Transportation. "When they do hit somebody, they do a lot more damage. It's the single biggest focus if you're preventing people from being killed."

A recent report found speeding declined by two-thirds and pedestrian injuries by 23 percent in New York City locations where speed cameras had been put in place, Martinez said.

If the bill passes, the Boulevard would receive up to nine speed cameras along nearly 12 miles from the Philadelphia border with Bucks County to the Ninth Street intersection near Hunting Park. The cameras would be advertised by warning signs every two miles.

"I think everyone can really agree that's the most important place in the state to do that," said Michael Carroll, the city's deputy managing director for transportation and infrastructure systems.

Roosevelt Boulevard, a 12-lane divided thoroughfare, carries about 90,000 vehicles a day through residential neighborhoods and business districts. Between 2011 and 2016, the road had about 3,000 crashes, according to city data, causing more than 50 fatalities, 20 of them pedestrians. The road is the first priority of Philadelphia's Vision Zero program, designed to reduce traffic-related deaths and injuries in the city.

Fifty of Philadelphia's 134 red-light cameras are at nine Boulevard intersections, where violations have dropped.  At Grant Avenue and the Boulevard, for example, violations went from 25,673 in 2005 to 3,582 in 2015. A spokeswoman from AAA said the cameras had decreased right-angle crashes at the intersections they monitor as well.

The speed-camera tickets, like the red-light camera tickets, would not add points against a driver's license and would not affect automobile insurance rates.

The revenue from the red-light program funds transportation improvements statewide, with Philadelphia receiving 50 percent of that money, Carroll said. The money is often used for smaller road improvements and to supplement larger funding sources, and speed-camera revenue would help pay for similar projects. Every dollar of the nearly $19 million in unpaid violations represents money that could pay for curb improvements or streetlights.

Carroll was more concerned with the unpaid fines the PPA has accumulated, though not necessarily because of the lost revenue, he said. The red-light camera program doesn't exist to generate revenue, he said, but to prevent collisions in intersections.

"It's significant because it may also indicate the deterrent is not as effective as we would like it to be," Carroll said.

Unpaid violations start accruing penalties 30 days after they are issued. Those increase over time, and if the ticket remains unpaid for 180 days it is referred to a debt collection agency. The PPA successfully collects about 18.5 percent of violations referred to debt collection. One of the challenges, said Corrine O'Connor, a deputy executive director with the PPA, is the number of violators who are not Philadelphians and don't have any fear of being booted by the PPA.

Last month, though, the PPA approved contracts with Penn Credit, Progressive Financial Services, Sabatina & Associates, and Harris & Harris to all handle debt collection. Each would keep 18 percent of the collected payments, PPA officials said, rather than the 40 percent the sole previous vendor, Debt Litigation Specialists, kept. That company was created by Sabatina & Associates.

The law firm and collection firm are run by John Sabatina Sr., the longtime Democratic leader of the 56th Ward in Northeast Philadelphia. Sabatina did not respond to requests for comment.

The change is expected to save the PPA $325,000 a year.

"We felt that would encourage competition within the four vendors as they were trying to collect," O'Connor said. "They would come up with new initiatives."

Taylor said he was not aware of the growing balance of unpaid red-light tickets in the city.  He suggested keeping an eye on that becoming a problem during the speed camera's five-year pilot program status.

"If that continues, if we see over a five-year period that people ignore them, then we could adjust the legislation," he said. "We could make it more of a criminal offense, more like a speeding ticket given to you by a police officer."

Simply operating the red-light cameras has eaten up a larger share of the program's revenue recently. Last year 65 percent of all revenue, nearly $10 million, was spent on expenses for the program. In 2015, 66 percent of all revenue, $8.6 million, was spent on expenses.

From 2010 to 2016, the cameras have cost the PPA $54.7 million to operate, about 56 percent of the revenue the program has brought in. In New York City, expenses consumed about 34 percent of revenue from 2010 to 2016, though Martinez said that city's expenses are less onerous than the PPA's because it is no longer adding cameras to the network.

The cameras are rented for a monthly fee from a vendor who also is responsible for maintaining and installing cameras, and handles processing of the violation notices. The PPA recently shifted the contract for equipment and maintenance from Xerox to an offshoot of that company, Conduent Local & State Solutions. The change should save about $1,200 a month per camera, PPA officials said.

"I would hope that we do see the expenses fall over time so that there's more available for the program itself," Carroll said.