A full-size charter bus filled with children barrels up Mount Diablo, honking as it whips around blind turns while taking up both lanes of the narrow road and nearly running cyclists off the pavement.

The rear wheels of a school bus descending from the top of the mountain slip off the side of the road after the driver says he wouldn’t take his children on the ride.

Frightening new videos of wide buses carrying school children up and down the narrow roads and through the tight curves of Mount Diablo make clear that the state must act before motorists, cyclists or scores of children are killed.

The good news is that the videos (here and here) have grabbed the attention of state Sen. Steve Glazer, D-Orinda, and Assemblywoman Catharine Baker, R-Dublin, who have called for meetings to discuss vehicular safety on the mountain.

“These videos clearly show unsafe conditions for cyclists and bus riders,” Glazer wrote. “These are unacceptable circumstances and the parks department and highway patrol must give this matter urgent attention.”

State parks spokeswoman Gloria Sandoval admits “there is a public safety issue.” The bad news is that the person who should be leading the charge, park Superintendent Ryen Goering, generally dismisses the concerns. As he has with past safety issues, Goering drags his feet, resisting change.

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It’s a shame that it consistently requires political pressure to ensure safety on Mount Diablo. But if that’s what it takes, so be it. With increasing numbers of cars and bikes navigating the two narrow roads up the mountain, safety must be paramount.

Administrators at The Athenian School, a private school at the bottom of the road leading up the south side of the mountain, got ahead of the curve, so to speak. Last summer, school leaders stopped sending their students up in full-size buses, opting instead for carpooling and vans.

That’s the right solution. The reality is that the roads on Mount Diablo cannot safely accommodate full-size buses. It doesn’t take a traffic engineer to recognize that buses cannot negotiate the blind, hairpin turns without taking up both lanes — a recipe for a collision with oncoming traffic, whether it’s a car or a bicycle.

That should be clear to anyone navigating the mountain or watching the newly released videos, shot by Al Kalin, leader of Mount Diablo Cyclists, who usually rides on the mountain three times a week.

If not for his tireless pursuit of records and data, we would not have known that from 2010-14, there were at least 20 collisions on the mountain in which cars on the wrong side of the road hit cyclists. That prompted Glazer and Baker to lead the successful charge for lane striping on the two roads and the warning signs to drivers not to pass on blind turns.

Now Kalin, after seeing and videotaping the buses full of children on the mountain, is pushing for more changes. I’m right there with him and grateful for his tenacious efforts for safety — as should all motorists, cyclists or parents with children who have traveled the narrow roads. He’s doing what Goering should be.

To be sure, no one wants to keep kids off the mountain. Quite the contrary. The goal should be to encourage their visits to one of the Bay Area’s great destinations but also ensure that their transportation is safe for them and everyone else.

Unfortunately, some bus drivers seem oblivious to the danger. Like the one at the wheel of the white Charter Brothers bus who increased the already high risk by driving at 25-30 mph up the mountain on July 17, nearly running cyclists off the road.

The bus was carrying school age kids from a Pleasanton science and nature program. When City Manager Nelson Fialho on Thursday saw the “obviously very disturbing” video of the speeding bus, he immediately canceled the planned Friday trip up the mountain and the contract with the bus company.

“The owner of the company needs to be responsive to me in terms of what the hell is going on,” Fialho said. The company didn’t return calls seeking comment.

At Michael’s Transportation, the operator of the bus that scooted off the road on the descent from the top in May, Chief Operating Officer April Brown hung up on me when asked to discuss the dangers of driving on the mountain.

The kids on that bus were from Stratford School in Pleasanton, where Adam Brown, a school director, did not return calls seeking comment. As a school official, he owes the public and parents an explanation.

Ignoring the problem won’t make it go away. For the sake of everyone on the mountain, there must be immediate changes.