Date: 201311
Local time of day: 1201-1800
Location: ORD.Airport, IL
Flight conditions: VMC
Aircraft: MD-83
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Taxi
ATC / advisory: Ground ORD
Second aircraft: EMB ERJ 145 ER/LR
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown
Second reporter function: Pilot Flying; First Officer
Anomaly: Conflict Ground Conflict; Critical
Detector: Person Flight Crew
When detected: Taxi
Result: Flight Crew Took Evasive Action
Contributing factors: Human Factors; Airport
Primary problem: Human Factors

Narrative: After landing on Runway 28C and clearing at P1; we were cleared to taxi east on P to GG and hold short of Runway 28R. Approaching GG on P; the Ground Controller cleared us to cross Runway 28R; turn left onto N; right on EE and hold short of D. The First Officer's read back was not quite correct; so the Ground Controller repeated the instructions; except that he said we were no longer required to hold short of Taxiway D and we were cleared to taxi to our gate. I proceeded as instructed and when we turned right from N to EE there was an Air Carrier leaving the international ramp moving towards Taxiway A to the west out of our way. As we approached Taxiway D; out of the corner of my eye; I saw an E-145 taxiing west bound on D at a very high taxi speed. We were both going to reach the intersection of EE and D at the same time. I aggressively applied the brakes and flashed my taxi light to get the pilot's attention but he did not slow at all. Had I not seen him; we would have been impacted in the cockpit area on our right side. As it was; when I stopped; their left wing tip passed no more that 20 to 30 feet from our nose. As I was stopping; the Ground Controller noticed the conflict and thanked me for giving way. He said the RJ was being moved by Maintenance and was 'not supposed to be there.' I never heard any radio call from the Embraer and I surmise that they were on a different Ground Control frequency then we were. I do not know if the conflict was the result of a coordination mistake made between two ground controllers or if the Embraer did not follow the clearance they were issued? I do know that the Embraer was taxiing at an excessive speed and that they did not see us prior to arriving at the intersection. With the introduction of the new Runway 28C/10C; the new taxi routes seem to me to send a lot of arriving and departing aircraft through a very congested area around taxiway EE. In my 20 plus years based in ORD; I have never understood the logic; with respect to safety; of using multiple Ground Control frequencies for arriving and departing planes that are physically moving in close proximity to each other. With the addition of this new runway and a third Ground Control frequency; I think these types of conflicts are likely to continue to occur.


Second narrative: While taxing on Taxiway EE; fuel farm between Taxiway N and D; blocked our view of an EMB-145 taxing west on D. As the Embraer passed by I could see clearly into the cockpit and the mechanic in the left seat didn't even see us; and appeared to be on a cell phone. Ground told us they should have given way and he would look into it.I suggest they move the fuel farm off the airport for better vision between crossing taxiways. Use same ground frequency for better situational awareness. Have mechanics tow aircraft; or have it done by pilots.


Synopsis: An MD80 taxiing to the gate after landing at ORD had to stop abruptly for an E-145 being taxied by Maintenance; which taxied in front of their cleared path at a high rate of speed.