The "Frontage Road" flanking a high-speed suburban highway

Frontage roads are the awkward waiting rooms of the American highway. They exist because we built roads so fast that stopping for a taco would literally cause a pileup.

It’s a clever, slightly desperate hack. By peeling off the "stop-and-go" traffic into a parallel lane, engineers protect the high-speed flow of the main road. It keeps the highway moving, but creates a weird purgatory of strip malls and gas stations that are technically accessible but physically hostile.

We basically built a second road just to apologize for how fast the first one is.

If it's so 'hostile,' how does a person actually get around?

You’re not just invisible; you’re an obstacle. These roads are designed for the 'turning radius' of a semi-truck, not the stride of a human. To get from a hotel to a diner, you’d often have to dodge three lanes of merging traffic and trek across a sun-scorched asphalt desert.

There are rarely sidewalks because, to an engineer, why would a person ever be outside of a two-ton metal box? It’s a landscape built strictly for machines, where being a pedestrian feels like being a glitch in the simulation.

Who actually signed off on a design that ignores humans entirely?

It all comes down to a metric called "Level of Service." To a traffic engineer, success isn't measured by how happy you are walking; it's measured by how many cars can zoom through without touching their brakes.

In this math, a pedestrian isn't a neighbor; they are a "conflict point." You are literally a variable that messes up the flow. Engineers treated these roads like high-pressure plumbing for vehicles, and you don't put sidewalks inside a pipe.

If the cars stay at 50mph, the engineer gets an A+. If you have to trek through a muddy ditch to get a sandwich, that simply wasn't on the grading rubric.

Wait, so a road with zero people on it is a perfect score?

Exactly. In the world of LOS, an 'A' grade looks like a post-apocalyptic movie where the hero drives through a deserted city at top speed. It’s the 'Goldilocks zone' of asphalt: no brakes, no pedestrians, just pure velocity.

If you add a crosswalk or a bus stop, the grade drops because those things might make a driver tap their brakes. To an engineer, a vibrant street full of people is just a 'failing' pipe that needs to be 'unclogged.'

We’ve essentially optimized our cities to be most successful when they are completely devoid of human life.

How do they actually 'unclog' a street that has too many people?

They perform what I call "urban liposuction." If a sidewalk is too popular, they’ll narrow it to add a turn lane. If a crosswalk slows down an SUV, they’ll just remove the paint and tell you to walk half a mile to the nearest light.

It’s all about "capacity." They’ll chop down shade trees to gain six inches of asphalt, turning a neighborhood stroll into a high-speed gauntlet where you're constantly checking your blind spot for a bumper.

The goal is to create a "stroad"—a miserable hybrid that’s too fast for humans and too cluttered for cars. It’s like "fixing" a park by paving it over so nobody trips on the grass.