Narrative:

I was holding short runway xxl full length which is taxiway X. I requested takeoff clearance. Tower had a fast jet coming in and the controller told me to cross runway xxl; but hold short runway xxr at [taxiway] X. I cleared xxl but I was actually holding short [taxiway] Y. Tower called and gave me clearance to depart runway xxr. I took a left on to Y thinking it was xxr and took off. I realized I was on the taxiway Y right as my wheels left the ground. I sidestepped right and than tracked xxr. Luckily for me and everyone else there was no one crossing the taxiway. I believe there were many things that caused the problem. I was late and rushing to get to a project on time. I had become pretty familiar with the airport and their operations. This caused me to be more relaxed and confident. While I normally always use my taxi diagrams I figured I didn't need it right in front of me. I knew exactly where I was going via the same taxiways I used many times. That all changed when I was told to cross to the right side and depart xxr. Next mistake was to take the intersection departure. I was asked if I could accept xxr at X which I agreed to. By taking the intersection departure I took away two things that would have helped me. Since it was an intersection departure I knew I wouldn't see the threshold or the numbers. When I didn't see either it did not bother me. I did a rolling takeoff and while on that roll my right engine shuddered just enough for me to look inside at my engine instruments. I then glanced at the airspeed and rotated. I never looked straight out down the taxiway. I used my peripheral vision. My head was just to inside the cockpit. My heading indicator and compass didn't help either as this was a parallel taxiway. Taxiway is good size which didn't help much either. Not the tower's fault; but I also didn't get any radio calls. I'm almost 99.9 percent sure he actually didn't see it happen. I was the first to notice and I sidestepped the runway. I accidentally keyed the mic and said 'crap' that's when I believe tower first noticed. The whole thing was bad and stupid; dumbest thing I've done in my life; airplane or not. Before this I had never even been close to making a big mistake like that. I will never let my guard down again. I will not accept intersection departures. I will maintain situational awareness and not rush.

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Original NASA ASRS Text

Title: PA23 pilot reported taking off on a parallel taxiway because of lack of situational awareness and time pressure.

Narrative: I was holding short Runway XXL full length which is Taxiway X. I requested takeoff clearance. Tower had a fast jet coming in and the Controller told me to cross Runway XXL; but hold short Runway XXR at [Taxiway] X. I cleared XXL but I was actually holding short [Taxiway] Y. Tower called and gave me clearance to depart Runway XXR. I took a left on to Y thinking it was XXR and took off. I realized I was on the Taxiway Y right as my wheels left the ground. I sidestepped right and than tracked XXR. Luckily for me and everyone else there was no one crossing the taxiway. I believe there were many things that caused the problem. I was late and rushing to get to a project on time. I had become pretty familiar with the airport and their operations. This caused me to be more relaxed and confident. While I normally always use my taxi diagrams I figured I didn't need it right in front of me. I knew exactly where I was going via the same taxiways I used many times. That all changed when I was told to cross to the right side and depart XXR. Next mistake was to take the intersection departure. I was asked if I could accept XXR at X which I agreed to. By taking the intersection departure I took away two things that would have helped me. Since it was an intersection departure I knew I wouldn't see the threshold or the numbers. When I didn't see either it did not bother me. I did a rolling takeoff and while on that roll my right engine shuddered just enough for me to look inside at my engine instruments. I then glanced at the airspeed and rotated. I never looked straight out down the taxiway. I used my peripheral vision. My head was just to inside the cockpit. My heading indicator and compass didn't help either as this was a parallel taxiway. Taxiway is good size which didn't help much either. Not the Tower's fault; but I also didn't get any radio calls. I'm almost 99.9 percent sure he actually didn't see it happen. I was the first to notice and I sidestepped the runway. I accidentally keyed the mic and said 'crap' that's when I believe Tower first noticed. The whole thing was bad and stupid; dumbest thing I've done in my life; airplane or not. Before this I had never even been close to making a big mistake like that. I will never let my guard down again. I will not accept intersection departures. I will maintain situational awareness and not rush.

Data retrieved from NASA's ASRS site as of July 2013 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.