Yellow reflective traffic signal border was an award-winning idea: Roadshow

Q: Do you know the backstory of the thin yellow border you see around many stoplights? It’s amazing how such a small border can make the stoplight pop out visually from the background. Whoever came up with this idea deserves an award.

Tom Darby, San Jose

A: The yellow frames around the perimeter of traffic lights are called reflective backplates. They are designed to help motorists see the signals more easily during morning and evening hours, in areas of visual clutter where the lights might otherwise be obscured, and in areas where lights are oddly spaced.

Another major reason for adding reflective backplates is to make traffic signals more visible when a utility company shuts off power to reduce the risk of a wildfire. While many traffic signals have battery backups, an extended blackout could drain those batteries. Priority for installing reflective backplates is given to signals in areas where wildfires are more likely to break out.

Q: Could you get some numbers from the CHP on collisions relative to rainfall? I’m wondering about this because in the last week, two close friends and one sister were involved in collisions. Everyone survived and, thank you airbags, injuries were trivial. Usually, it’s only every two or three years that someone I know is involved in a collision.

In my sister’s case, she was driving on the freeway when a pickup truck behind her lost control, clipped a rear corner of her car and sent her car spinning off the road. She said, “Until something like this happens, you don’t really understand just how much control you don’t have. Everyone is hurtling down the freeway, the littlest thing can go wrong and cars collide.” She added, “It was heavy rain. The traffic was going about 65. It should have been going 50.”

I had to drive home from San Francisco in heavy rain a few days ago. I chose Interstate 280, even though it was longer, because Highway 101 is more prone to flooding. I also drove 55, in right-hand lanes, the whole way.