It also likely aims to slow down bikes and scooters

It certainly succeeded with that!

No, not looking at their smartphone

Humans don't have superfast reaction speed and that metal gate could have been open on their prior trips through the area so they likely where on autopilot coupled with human reaction timing while at speed meant not enough time to course correct

Don't assume everything bad happening to a person is caused by looking at a smartphone

Are you a boomer ?

Sorry if my comment comes off as aggressive, I'm just sick and tired of older generations stereotyping younger people and the "younger generations always staring at a smartphone" is a typical boomerism