First, a confession: I owe Detroit $1.50. My experience as a visitor trying to use public transit in an unfamiliar city may seem benign or comical, but it’s emblematic of inconsistent policies worldwide about how, and even if, riders should pay to get somewhere, and the penalties if they don’t. In extreme cases, it could mean arrests and jail time. It seemed simple enough in Detroit. I was in town for a convention, attending an off-site event with a colleague. A private shuttle was late picking us up, so I suggested walking two blocks to catch the new QLine light rail. The route worked on the honor system: There were no turnstiles on the platform, but a cop or fare collector could approach you on the train and ask for your ticket. We bought one at a self-service kiosk and attempted to purchase another, but it wouldn’t take my credit card. My cash was also rejected. We still only had one as the train approached. I could let my colleague ride ahead — except she didn’t know where she was going, so we both boarded. Some other riders cheerfully assured us, “It’s free today! You don’t have to pay!” Race shouldn’t be a factor in this story except it is. The people telling us not to worry were white, and laughing about the free ride. My colleague and I, both African American, were nervous the whole way. With visions of police encounters in my head, I silently rehearsed a weak explanation about the machine not working, wondering if a fare enforcer would buy it. To our relief, no one materialized, though afterward a QLine spokesman told me that the trolley was by no means free. We would have been allowed to pay if confronted, but in other cities, it could have been grounds for arrest. The experience floats along a continuum of fare evasion scenarios: from obliviously riding free, as my fellow passengers may have done, to jumping a turnstile with unquestionable intent to evade the fare. New York may be the turnstile jumping capital of the U.S., or certainly used to be. In the early 1990s, the nation’s largest subway system reportedly tallied 230,000 fare evasion incidents daily, though not all involving turnstiles and very few prosecuted. That sparked then-New York Transit Police Chief Bill Bratton to step up enforcement as part of his controversial “Broken Windows” policing program. Evasion persists, with 25,000 prosecutions in 2016 and likely fewer than 10,000 this year, following Manhattan District Attorney Cyrus R. Vance, Jr.’s announcement in 2017 that his office would no longer prosecute most evaders. In Boston, the bigger evasion problem is college students swarming into crowded trolleys through all doors, not just the front one by the fare box. It’s a dilemma plaguing transit systems around the world: Should passengers be allowed to use every available door, some paying and some not, to board quickly and get the trains moving? Or should everyone be forced to the front to pay, at the cost of delaying the trains? The same problem affects buses. By their nature, subway stations are harder to breach, leading to more inventive ways of doing so. (The most creative I’ve seen, before electronic passes, was a Boston art student who meticulously drew a replica pass each month to wave to fare collectors.) Yet anti-evasion technology is also constantly evolving, such as sturdier or taller fare gates replacing flimsy turnstiles. New fare technology recently installed in London and being replicated in New York and other U.S. cities might further inhibit evasion, though London saw a slight increase in evasion on some bus routes. George Kocur, a retired Massachusetts Institute of Technology professor who worked on the algorithms for London, says technology allowing payment with a fare card, a credit or debit card, or your phone would render my Detroit experience obsolete. “The excuse of not being able to get a fare card, or not being able to use a ticket vending machine, or the line was long at the machine, etc., is less likely,” Kocur says. He also says systems requiring riders to swipe fare cards both when entering and exiting might lessen evasion. Turnstile jumping is often a crime of opportunity; few would do so in front of a police officer, and chances are low that conditions would be optimal for jumping at both ends of a trip. If a rider evades the fare getting on but pays at the exit, double-swipe systems may impose a significant surcharge for only paying one way. Yet the jury’s out on just how effective technology alone can quel evasion. Subways in Washington, D.C. and San Francisco already require exit swiping, yet a recent San Francisco Chronicle investigation placing a camera at a BART station shows jumping still a healthy pastime. So is the answer just good old policing? The Marshall Project’s analysis of New York enforcement shows arrests roughly coinciding with black and Hispanic communities. One explanation is it isn’t racial, but that’s where the crimes are. But unless the jumpers are one-way riders traveling to similar neighborhoods, why aren’t they arrested at the same rate on return trips? Do they suddenly stop jumping in areas where they work or go to school — or is turnstile jumping not equally enforced at all stops? Some groups defend and even advocate fare evasion as a way to combat regressive fees that disproportionately affect the poor. That may evoke compassion, but it’s like saying it’s fine to steal a loaf of bread rather than buy one with WIC benefits. There are other ways to accomplish equity: Seattle and other systems have already begun discounting fares for low-income riders, a solution increasingly possible with electronic fare technology, says Kocur. In the meantime, fare policies that support rather than hinder a transit system’s basic purpose of getting people where they need to go is a matter of maintaining the social fabric — like everyone agreeing that traffic should keep right. Just as there’s no sympathy for anyone driving on the left, what full-fare-paying rider wouldn’t want to see the book thrown at someone else sneaking through? Sounds good — unless you’re on the QLine in Detroit, attempting to explain a missing ticket. In that case and more broadly, there are no easy answers — as transit systems seeking a truly effective deterrent to evasion know all too well. Robin Washington is Interim Commentary Editor for The Marshall Project and a longtime transportation writer. He may be reached @robinbirk.