Jun 24, 2022 - News

Why Austin's traffic lights are horizontal

A view of the Capitol, with a traffic light in the foreground.
Check out that horizontal traffic light. Photo: Travis P Ball/Getty Images for SXSW

Out-of-towners are often surprised at Austin's horizontal — as opposed to vertical — traffic lights.

Zoom out: How unusual is the setup here? Our Axios colleagues in Raleigh, Atlanta, Chicago, Richmond, Salt Lake City, Denver, and Minneapolis-St. Paul told us the traffic lights in their towns were up-and-down.

What they're saying: Horizontal lights offer better vertical clearance — leading to less chance of damage to the signal infrastructure — and are less likely to be tossed about by gales, Jack Flagler with Austin's Department of Transportation told Axios.

  • "When the signal head is more in line with the mast arm on which it is mounted, it will create lower drag when winds are high," Flagler said.
  • ​​In vertically-oriented Atlanta, Axios colleague Thomas Wheatley tells us, "Occasionally you'll see one that's obviously been clipped by a delivery truck. It's just a mangled mess."

Yes, but: Most traffic lights are configured vertically so that people who are color blind know what color the light is, per an explainer by Eltec Corp., an East Texas-based maker of traffic equipment.

  • "Even if a driver can't distinguish the colors in a traffic light, they will know that they can go if the bottom light is illuminated."
  • "If traffic lights are horizontally configured, it's not possible for a color-blind person to know whether the green light is on the right or the left, which can cause serious problems."

Get smart: In some areas of Canada, horizontal traffic lights use different shapes to help drivers — the red light is shaped like a square; the yellow light, a diamond; the green, a circle.

The bottom line: The federal code in the Manual on Uniform Traffic Control Devices permits signals in a vertical or horizontal straight line, so local governments can choose to arrange them either way.

📫 Guess closest the number of traffic lights in Austin — this is like jelly beans in a jar — and you could win an Axios hat or water bottle.

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