Metro Transit is testing technology to see whether it can tell who is freeloading. For the next 10 days, drivers on three of the busiest bus routes will enter information into a computer when a customer can’t or won’t pay full fare.

The goal is to see whether the agency can collect enough reliable data to pinpoint when and where people are not paying. “If the data set is good, we may use it for working with Metro Transit police and say that Route X has high cases of fare evasion and it’s this stop and this stop and at these times,” spokesman John Siqveland said. He would not identify the routes.

Metro Transit provided 68 million bus rides in 2012, and about 4 percent of riders didn’t pay. Some people are allowed to ride for free: disabled veterans, children under 5, police officers and other special groups. But last year police issued more than 10,000 citations and warnings to riders who should have dropped coins or bills in the fare box.

“Fare evasion” is punishable by a $180 fine. A person also risks being banned from riding buses for a period of time, Siqveland said.

It’s not clear whether the problem is on the rise, but a larger transit police force means that more people are being caught. Metro Transit has expanded its police force to staff the opening of the Cedar Avenue Bus Rapid Transit line and the anticipated opening of the Green Line, the light-rail line between downtown Minneapolis and St. Paul.

Fares make up about one-third of Metro Transit’s revenue. Its budget is $300 million. Drivers have two choices when a customer doesn’t pay. They can state the fare in hopes the rider will pay. Or they can call for police to meet the bus. In many cases, drivers continue their trip to keep on schedule. “Delays are costly,” Siqveland said. It might not be worth it “if they are a nickel short of the fare and you have 40 people going to work.”

He said fare evasion is not a problem on the Northstar Commuter line or on Blue Line light-rail trains. Transit police who do compliance checks on the trains have found that 99 percent of riders pay their fares.