INDIO, Calif. -

Officials say a mechanical problem may have contributed to the horrific tour bus crash in Yucaipa.  Records show the California company that owns the charter bus failed more than a third of its random safety inspections.

So, how do you know that the bus you're riding in is safe?

Not every crash can be prevented but there are systems in place to make sure that the bus you are getting on is safe. California Highway Patrol is one of them, it's in charge of physically checking these buses.  But, there are things that you can do, too.

Tim Bannister, president of Celebrity Tours, says,"We are a the mercy of the mechanics.  sometimes you can't foresee something but we try to cover everything we can."

Celebrity Tours in Cathedral City says it inspects their buses daily.

"Before it ever leaves and that is the responsibility of the drivers, but we follow the guidelines that are set forth by federal regulators," said Bannister.  

State law requires charter buses to undergo maintenance every 45 days.

"I don't think there are a lot of companies that are out there necessarily ignoring rules or regulations and things I think they are all trying to do the right thing. Mistakes happen, it's human nature.  We try to avoid as many as we can," said Bannister.

The California Highway Patrol randomly inspects buses to make sure they are safe.

"We are the ones that have an inspection program in place to make sure that they are keeping up on their maintenance, the drivers aren't driving too many hours, and that they're properly licensed," said Officer Joe Zagorski with the CHP.

All bus drivers, must have a commercial license.

"A commercial driver is considered a professional driver.  They require a lot longer driving experience they also require a much cleaner record," said Zagorski.

Celebrity Tours gives it's drivers an additional test.

"You don't want just anyone sitting behind the wheel from the standpoint of the cost of the bus but also the safety of the people you're dealing with lives," said Bannister.

In Yuciapa, 7 people died.  The NTSB continues to investigate, but witnesses say the charter bus lost its brakes while driving down the steep mountain road.  Tim Bannister said that can happen when breaks over heat.
 
"The brakes over heat from over use on a downhill and all of a sudden they lose breaking power," he said.

Bannister says he won't allow his buses to drive on a steep road without an additional engine break installed on the bus.

"Its a restricter, basically it will slow the bus down without even applying the breaks," said Bannister.

Right now it's not a state requirement to have that type of break installed, but Bannister believes it should be.

"You are talking about a minimal investment, but I think as bus owners it ought to be something that we take upon ourselves or own personal responsibility and not wait for he state to make that a mandatory item," said Bannister.  

But what can you as a passenger do to make sure you get to your destination safely?  The CHP says if you see a problem don't hesitate to pickup your phone and call 911.

"Our officers have no problem stopping a tour bus with 35 people that is exceeding the speed limit and giving a ticket to the driver.  Our concern is to get everyone home alive," said Zagorski.

"I think that it is up to us as bus companies to be responsible for the lives that we are moving around on a day to day bases.  That is a big responsibility and we don't take it lightly," said Bannister.

At this point we don't know if the charter bus involved in the deadly accident had that engine break, but the investigation is ongoing.