If you were anywhere near Boston last week, you may have seen the viral footage: more than 100 bicycles, scooters, and dirt bikes careening into the O'Neill Tunnel on Interstate 93, weaving through cars, cutting across lanes, popping wheelies, and generally treating the highway as their own playground. A police superintendent fumed that the cyclists were “wreaking havoc.” Drivers said it was “scary” to encounter the horde. Social media users called it “terrifying,” “lawless,” and “crazy.” Many wondered why, except for a single rider who crashed into a State Police cruiser, none was arrested.

They’ll get no argument from me: It was idiotic and incredibly dangerous — and a miracle no one was struck by a car or truck.

Fortunately, no one insists that bicycles belong on the interstate. But as I watched the video of the scene, I couldn’t help wondering how long it will be before the unrelenting bicycle lobby begins to demand just that. After all, if it makes sense to carve bike lanes out of Massachusetts Avenue, Beacon Street, and other congested thoroughfares in Boston, Cambridge, and Brookline, why shouldn’t the logic extend to I-93 as well?

I have long argued that busy arterials — built for the cars, trucks, and buses that transport the overwhelming majority of people moving through the nation’s cities — are no place for cyclists. Bicycles can be a charming, even exhilarating, way to get around. So, for that matter, can electric scooters and skateboards. But they shouldn’t be mixed into the flow of motorized traffic on roads that are already too clogged. To pretend otherwise is dangerous and irresponsible.

Yet policymakers in Boston, as in many other cities, have caved to the insistent demands of the bicycle lobby, converting lane after lane to cyclists’ use. The objections that keep bikes off the highway — the roads aren’t designed for them, the constant risk of collisions, the traffic slowed and worsened — are equally true on our surface streets. On I-93, everyone grasps the absurdity. Yet on Mass. Ave., we’re expected to swallow it whole.

This is no minor policy debate. Bike lanes have become a flashpoint in the Boston mayoral race. Incumbent Michelle Wu at times seems to be laying down bike lanes as fast as her public works crews can paint stripes and bolt in flex-posts. While she touts the benefits of converting driving lanes for the benefit of cyclists, it isn’t clear that she has given much thought to the costs.

But the public has. In a Boston Globe/Suffolk University poll last month, half of respondents said bike lanes have made it slower and less convenient to get around. Only 18 percent said bike lanes have made transportation safer or easier. Wu’s challenger, Josh Kraft, has tapped into the backlash, calling the rollout “poorly thought out” and pledging to pause construction — and remove those lanes that have worsened safety. Wu counters that the quick-build barriers are only temporary expedients. But for drivers stuck in traffic that barely creeps along, and for businesses coping with lost loading zones, temporary feels permanent enough.

The politics of bike lanes have become a stand-in for something larger: who city streets are really for. Are they lifelines of transportation, commerce, and emergency response? Or are they canvases for “green” experiments that elevate a minuscule minority of cyclists above the far greater number of drivers, bus riders, and delivery vehicles that keep the city moving?

Cycling enthusiasts love to point to Amsterdam or Copenhagen as proof that American cities could be remade into bike utopias. But Boston isn’t Amsterdam-on-the-Charles, and it isn’t going to be. European cities never sprawled like ours; their dense cores were laid down centuries before the automobile. When they expanded cycling infrastructure, it wasn’t by striping lanes onto their busiest boulevards but by redesigning whole districts, often pushing cars out entirely. And there is a cultural gulf, too. Europeans are more willing to accept sweeping mandates from above. In America, there is a deep-rooted ethos of freedom, space, and near-universal car ownership.

The scene on I-93 last week was rightly condemned as reckless. Dirt bikes and scooters had no business weaving among SUVs and delivery trucks. But if it’s lunacy to imagine a “protected lane” for cyclists on the interstate, how can it be good policy to carve such lanes into the hectic surface roads that keep Boston alive? The hazards and inconvenience don’t vanish just because the speed limit drops from 65 to 35.

Either our roads are for moving the greatest number of people and goods safely and efficiently, or they are stages for a boutique vision that benefits the few while burdening the many. On I-93, everyone sees the folly. On Massachusetts Avenue, it ought to be just as clear.