Lawrence shoppers pay a little bit more, but Lawrence motorists get a little smoother ride.

That was the idea behind a three-tenths-of-a-cent infrastructure sales tax approved by voters in 2008, and now a report out of City Hall says motorists are starting to feel the benefit.

The city’s latest pavement condition index — a report that provides a numerical score for every section of street in the city — shows that during the past four years the condition of city streets have made the largest leap forward in recent memory.

“It is too soon in our program to declare victory, but we think this shows we are continuing to make good progress,” said Mark Thiel, assistant director of public works. “We think we’re making good decisions on how to spend these dollars.”

A key fact in the report is that 20.5 percent of all streets are rated “unacceptable.” That doesn’t sound too great, but city officials say it’s a significant improvement over the 31.5 percent that were rated unacceptable at the end of 2005. At the end of 2009, the number still stood at 29.8 percent.

“When the 2008 sales tax went into place, that gave us quite a bit more resources,” Thiel said. “That has had a huge impact.”

The report also highlights the amount of work left to be done. City engineers, who inspect and measure every street as part of the ranking process, classify a street as unacceptable when they believe normal maintenance projects could not significantly improve the street. In other words, a street rated unacceptable needs to be rebuilt.

The city has almost 325 lane-miles of street, so 20 percent that need to be rebuilt is still more than the city’s budget can handle.

“The challenge is this always will be an ongoing process,” Thiel said. “We’re never going to be able to say we’ve met all the goals and we can leave the roads alone for awhile.”

The city is budgeted to spend more than $5 million on major rebuilding projects this year, including the intersection of 23rd and Iowa streets, a portion of Wakarusa Drive, a portion of Bob Billings Parkway west of Wakarusa, and the intersection of Sixth and Iowa streets. In addition the city will spend about $4.2 million on more standard maintenance projects such as repaving and patching programs. The $4.2 million total is about how much the city was spending on routine maintenance before the sales tax. While the city has increased the amount of sales tax dollars devoted to routine street maintenance, funding from other sources, such as the state’s gas tax, have struggled to keep pace.

Other numbers from the report include:

• The average condition score for a street is 75.5 on a scale of 1 to 100. That’s up from 70.2 at the end of 2009 and 69 at the end of 2005.

• The number of potholes reported by citizens in 2013 was 260, down from 320 in 2012 and 675 in 2011. Thiel said the pothole numbers have been impacted by milder winters, but also are the result of the city having the streets in better conditions before winter begins.

• The amount of preventive crack sealing of city streets has soared. In 2013, the city used nearly 110,000 pounds of crack sealing material, up from about 63,000 pounds in 2011.

City commissioners will review the street report at their 6:35 p.m. meeting on Tuesday.