Public Works is trying to take the mystery out of paving.

On a recent Tuesday morning, trucks filled with asphalt fed the black steaming material into a paving machine as it crept along Saline Street in The Run. Klaus Libertus has lived there for two years and said, before the paving crew arrived, driving down the street was "vibrating."

But it had its benefits.

“If you had kids in the back you wanted to get to sleep, it would help," he said. "I mean they used to say 'the patches had patches.'"

Libertus said long-time residents said the street had not been paved in 30 years. That probably would not surprise Pittsburgh Public Works director Mike Gable.

“If you go for 20 years of paving less than 45 miles a year and you’ve got 900 miles of asphalt streets, that pretty much tells you in 20 years your system has failed,” Gable said of the seemingly always underfunded repaving budget line. “Every one of your streets is going to be in bad shape.”

The city of Pittsburgh is budgeted to spend $613 million on operating and capital expenses this year. Of that, roughly $15 million will be spent on paving projects. Despite representing just slightly more than 2 percent of the budget, it is some of the most sought after money in the city.

In 2016, nearly 8,000 paving requests and pothole complaints came into Pittsburgh’s 311 center. That works out to about 22 calls, emails or tweets every day.

This year, the city expects to pave between 50 and 60 miles of city streets based on the budget passed in December. But with demand from residents out-striping supply, the city has to make some tough decisions.

Pittsburgh City Councilwoman Theresa Kail-Smith said her office takes at least a call a week asking for a specific street to be paved in her district.

“Your heart is always wanting to help more, that’s what we do, we want to help more people," she said. "So, when you have to say no to someone, it’s just gut wrenching."

Despite chairing council’s public works committee, Kail-Smith sends all of the request directly to Gable’s office.

In the past, those request might have been ignored or moved to the top of the list. It all depended on the political clout behind it, said former city councilman Jim Ferlo.

“I tried not to actually get involved too much in asphalt because it was always a loosing proposition,” said Ferlo, who served on city council from 1988 to 2003.

“I would never B.S. people,” Ferlo said, adding that he could only pass along requests to public works.

When Pittsburgh Mayor Bill Peduto was a member of city council, he tried to point out the arbitrary nature of the paving program by suggesting that he would place a bobblehead doll on his car’s dashboard and drive every street. The streets where the head bobbed the most would get paved, he said.

After Peduto was elected, the city launched a more data-driven system for paving with the help of a company called Cartagraph and its electronic sensing equipment.

“They rode every street segment in the city of Pittsburgh and gave us an assessment of those streets,” Gable said. “We have been able to use that data to compile the program for 2017. Actually, we created a two-year program.”

The plan is to update that data every three years.

Other factors are considered when choosing the streets, including 311 calls, observations from public works supervisors and, of course, input from council members.

“We like the input from City Council," Gable said. "I mean, it’s their constituents that are calling them and looking for the streets to be resurfaced. We like to spread it around and make sure everyone gets a little piece of the pie.”

Planned utility work also has an impact on choosing which streets will get paved.

Ferlo said, in the past, there was no coordination between the city and the utility companies. It was not unusual for the city to pave a street only to have it dug up a few weeks later by a utility doing routine line repairs. In fact, in the late '90s there was open speculation on council that the utilities were intentionally choosing recently paved streets because they were easier to dig in that streets that had hardened over time.

By law, utilities must repair and repave streets they disturb, but they only have to fix the portion of street they dig up. So, Gable started to meet regularly with the utilities to find out where they planned to do maintenance work. Then he drew up a plan to share the burden.

“For example, the utility company wanted to do [dig trenches in] 20 streets. And so what we worked out was they trenched 20 streets, but we got them to pave 12 [streets] curb-to-curb and we paved the other eight curb-to-curb,” he said.

Gable said he was able to add about 8 more miles to this year’s paving program through the coordination effort.

But even that is not enough. Gable said to catch up with the backlog of streets, he needs to be paving about 100 miles a year. That’s compared to this year’s roughly 60 miles.

He said he gets thank you notes from time to time from people thanking him for paving their side street. He said he hopes they enjoy it, because it might never happen again in their lifetime.