Out of 5 million Lynx riders, how many are cited for not having a ticket? We checked.

CHARLOTTE, NC (Steve Harrison/The Charlotte Observer) - The Lynx Blue Line is perhaps the city's biggest – and most expensive – use of the honor system.

The transit system lets people board without checking for a ticket, and fare inspectors make periodic ticket checks and write $50 citations for scofflaws.

But a review of data shows that few people are nabbed by inspectors, and the $50 fine is among the lowest of the nation's "proof of payment" light-rail systems. Last year, fare inspectors issued 545 citations. Of those, a judge upheld the $50 fine for 368 cases.

About 5 million passengers ride the Lynx each year. That number will likely double starting Friday, when the 9.3-mile extension opens.

Are there few passengers riding without a ticket? Or is the Charlotte Area Transit System not finding them?

Tom Stack has commuted on the Lynx daily from the New Bern station to uptown for a year.

"I can definitively say that no one has ever asked for my ticket," said Stack, who uses a cellphone app to buy tickets.

When he first started riding a year ago, he said more people were talking about having their tickets checked.

"But it feels like you don't hear about it much anymore," Stack said.

The Charlotte Area Transit System's "proof of payment" system is not unique.

The American Public Transportation Association said it surveyed 23 cities with light-rail systems, and 18 said they allow passengers to board without going through a turnstile.

Polly Hanson, APTA's director of transit security/risk and emergency management, said cities with light-rail systems have little choice but to rely on proof of payment. The reason is that many stations are at street level, so it would be difficult and unsightly to build fencing around them.

"It's the configuration of the system," she said. "A lot of times the stations are at-grade. You are getting on the train from almost street level."

A review of CATS data shows that the Lynx Blue Line's fare inspectors – who are both private security and Charlotte police – are far more likely to give passengers a warning if they don't have a ticket. There also has been a slight increase since 2013 in the number of people who have had to pay a $50 fine.

Last year, the fare inspectors wrote 4,751 warning citations and 545 state citations.

In 2013, there were only 2,102 warning citations written and 304 state citations. Of those state citations, 254 resulted in a $50 fine.

The Lynx carried 4.8 million passengers last year and 5 million passengers in 2016. That's about 15,000 passenger trips on an average weekday.

Krystel Green, a CATS spokesperson, said fare inspectors are able to determine whether it's a passenger's first offense without a ticket. If they have been cited before, it's less likely they will receive a warning the second time.

While proof of payment is common, other cities have higher penalties to discourage cheating.

Denver's fine can reach $106.50. In Norfolk, Va., the fine is $250. San Diego fines ticket-less passengers $75 for a first offense and $500 for a second offense. Minneapolis has a $180 fine and Houston's fine is $75.

Phoenix's fare-evasion fines range from $50 to $500.

On the low end, Cleveland has a $25 fine and Dallas has a $50 fine.

Green said CATS hasn't discussed increasing its fines.

A common complaint among Lynx passengers is that people are bypassing the station's ticket-vending machines and riding for free.

But there are numerous ways to ride legally without buying a ticket at the machines.

Many have weekly or monthly passes that allow them unlimited rides. Passengers can also buy tickets on a new cellphone app. And when the Blue Line extension opens Friday, UNC Charlotte students can ride for free. They will pay a mandatory fee of $25 per semester.

In 2016, CATS received $10,500 from people who paid their $50 fines. That year, CATS had $4.5 million in revenue from its ticket-vending machines.

Last year, the transit system received $12,500 in fines. Total Lynx revenue from the ticket machines fell significantly, to $3.6 million.

It's unclear why revenue fell so steeply. CATS said the old ticket machines – which have since been replaced – were often broken. It's also possible more people are buying tickets on a mobile app instead of the ticket machines.