Passengers aboard a Megabus were forced to steer the bus to safety Monday after their driver passed out at the wheel.

The bus was traveling from Philadelphia to Pittsburgh along the Pennsylvania Turnpike when the bus started to swerve. Passenger Stefon Braxton told Channel 4 News Pittsburgh that when he looked out the window ,he saw two tractor trailers driving alongside the bus keeping it from swerving more.

The driver, who was without her blood pressure medication, had blacked out.

"I was first alerted when people started to shout to stop the bus, slow down, pull over. This was on the turnpike, which is two lanes. There was a tractor trailer on our right and a tractor trailer on our left and we were traveling at a very high rate of speed,” passenger Michael Dunn told CBS Pittsburgh.

As it turned out, one of the passengers had just received his commercial drivers' license. Taking matters into his own hands, he jumped into the driver's lap and started steering the bus while other passengers moved the driver. According to WXPI, the tractor trailers helped the passenger steer the bus -- which was literally bouncing between the two trucks -- off the road.

Megabus sent a relief driver to pick up the passengers and bring them to Pittsburgh.

"The driver who took ill is doing well and will receive further checks from the doctor,” a Megaus representative told local media. “Safety is our absolute priority and, as a matter of course, we are investigating the incident. We apologize to Megabus passengers for the disruption to their trip."

In August, a Megabus crashed into a bridge support pillar on an Illinois interstate after blowing a tire, causing one death and dozens of injuries. A number of lawsuits have resulted from the wreck. A Megabus also crashed into an overpass in upstate New York in 2010, and the driver was acquitted of homicide this February.

In 2011, a Megabus driver was charged with a repeat DUI while on duty.