Context? there are multiple words so there are more than one "definition" . Sounds like you got into a scrape or fender bender!?
Ugh hope you didnt get DUI and werent drinking. Seems to be common with that lane maintaining thing you talk about.
What is the exact definition of failing to maintain a lane?
As a licensed driver, you’re probably well aware of the rules of the road. One of the many traffic offenses is failure to maintain lane. This simply means that a driver should remain within their designated lane and not cross over or touch the lines. When changing lanes, a driver must wait until it is safe to do so and signal properly to alert other drivers. If you were stopped by police for this traffic offense and were arrested for drunk driving after police conducted a DUI investigation, it is in your best interest to seek the advice of an attorney.
http://www.failuretomaintainlane.com/
Definitions of this offense probably vary by state, but here's the link for New Jersey's law:
http://www.expertlaw.com/forums/showthread.php?t=137720
Look at the first answer on the link.