On December 23, 1998, at 0905 Alaska standard time, a Cessna 207 airplane, N1864, sustained minor damage when it dropped into a ditch while taxiing for takeoff at the Ralph Wein Memorial Airport, Kotzebue, Alaska. The airline transport pilot and the sole passenger were not injured. The airplane was being operated under 14 CFR Part 135 as Grant Aviation, Inc., Flight 501 from Kotzebue to Noatak, Alaska. Night visual meteorological conditions prevailed at the time of the incident, and a company VFR flight plan was filed. The pilot told the NTSB investigator-in-charge (IIC) during a telephone interview on December 23, that when he called for taxi, the FAA Flight Service Station (FSS) told him that the main runway 08-26 was closed due to a vehicle sweeping snow, and that runway 17 was available. The pilot said he then attempted to taxi to runway 17, and followed tire tracks in the snow on what he believed was the taxiway. He saw automobile headlights coming toward him, then the runway 17 edge lights to his right side, and recognized he was no longer on the taxiway. He turned the airplane toward the runway lights, and the airplane fell into a ditch. Investigation revealed that the airplane had taxied off the taxiway, onto a road which parallels, and then crosses the taxiway at a shallow angle. The intersection is unmarked. The taxiway distance from the edge of runway 08, to the threshold of runway 17 is 1,463 feet. There are no taxiway lights or reflective markers along this route. Both the taxiway and the road were plowed. The pilot said that he had been stationed in Kotzebue since September. He had only used runway 17 three times, and always in the daylight. The FAA Alaskan Region Airports Division, and the State of Alaska-Department of Transportation have the installation of taxiway lights for this route depicted on the blueprints of a nonfunded, future project. Runway 17/35 is not used by air carrier aircraft seating more than 30 persons, and consequently it is not governed by 14 CFR Part 139. FAA Advisory Circular AC 150/5340-24 - Runway And Taxiway Edge Lighting Systems, states in section 4, Taxiway Edge Light Configurations: "lights should be spaced longitudinally not more than 200 feet apart to define the lateral limits of the taxiing path.... Closer spacing of the lights should be provided on ... entrances to taxiways from runways or aprons.... For low activity airports, elevated L-853 reflectors may be used in lieu of edge lights for outlining taxiing areas." No NTSB Pilot / Operator report was received from the pilot.