A bus driver who drove the wrong way on an I-25 carpool lane has resigned.The Regional Transportation District is not identifying the driver, whom the agency suspended after he drove about 5 miles north in HOV lanes intended for southbound traffic early Wednesday morning.7NEWS has learned that the driver drove around a closed gate and ignored two do not enter signs.For whatever reason the bus driver ignored those and went around the gate, said RTD Assistant General Manager Scott Reed.The incident was reported at about 5:30 a.m. when another RTD bus driver heading northbound spotted the wayward bus on I-25 at 58th Avenue and called dispatch.Once dispatch was notified, they told him to pull over and then to proceed at five to ten miles an hour, until he could get off the highway.Several motorists called 911 to report the wrong-way bus."I was just on the HOV lane near 58th Avenue and I-25 and there's an articulated bus that's heading northbound in the slow lane with its emergency flashers on, one man said, according to a 911 recording obtained by TheDenverChannel.com. "It's a little dangerous out there when you're hitting 55 and all of a sudden the bus is in front of you," the man said.State Patrol spokeswoman Trooper Heather Cobler said the agency did not have a patrol car in the area at the time.Denver police also received a report about the wrong-way bus."We did receive a call stating somebody saw a bus going the wrong direction," department spokesman Sonny Jackson said. "So we sent officers to the area, but were not able to locate the bus. No one was cited because the bus was never located."Reed said the driver normally worked in the East Metro area.He said the driver brought some passengers down to the market street station earlier that morning and was on his way back north in an empty bus when he drove onto the incoming HOV lanes.He drove down the 16th Street Mall to the mall shuttle turnaround behind Union Station, then got back on the Mall and turned left onto the HOV entrance ramp, Reed said.Traffic was light at that time of the morning. No cars were hit and no one was hurt."RTD takes this very seriously," said Reed. "We are conducting an investigation to determine how this could have happened."In the mean time, Reed said, Were doing safety refresher training and are sending bulletins to all drivers who operate in the HOV lanes, to remind them that gates being down and lighted signs on clearly mean do not enter.When asked how this incident reflects on RTDs safety reputation, coming on the heels of several recent accidents.Reed responded, We are very concerned about our safety record. There have been some accidents recently, but there is no real trend and nothing tying the accidents together. In this instance the driver did not follow procedures.Reed said theyre still trying to learn why the driver ignored the gate and signs.The results of drug and alcohol tests have not been released.