Drunken-driving experts and bus safety officials will join witnesses to a bus crash that killed 27 people when testimony gets under way Tuesday in a National Transportation Safety Board hearing. The May 17 accident occurred when a pickup truck going the wrong way on Interstate 71 slammed into a bus owned by the Radcliff First Assembly of God church. Authorities contend the driver of the pickup was drunk at the time. NTSB spokesman Allan Pollock said accident survivors probably will not testify because the agency doesn't want to traumatize them. The pickup driver, Larry Mahoney, 35, has been indicted on 27 counts of murder, 13 counts of first-degree assault, 44 counts of first-degree wanton endangerment and one count of drunken driving. It will be the worst drunken-driving accident in U.S. history if he is convicted on the final charge, according to the NTBS and Mothers Against Drunk Driving. The board will hear testimony on six issues, five of which concern drunken driving, Pollack said. The sixth involves bus safety. Pollock said testimony will be taken on the performance and capabilities of drivers under the influence of alcohol; the extent of the drunken-driving problem; and the effectiveness of alcohol education and treatment programs. He said the witnesses also will address the adequacy of sanctions Kentucky's courts impose on drunken drivers and the development of effective alcohol countermeasure programs like jail terms, fines and license revocation. The accident has raised questions about bus safety because all 67 passengers on board survived the impact but the victims died when the bus's gas tank was punctured, causing a fire that quickly engulfed the vehicle. The fire blocked the front door, leaving the rear emergency door as the only escape route. The safety issues to be discussed include emergency exits; the upgrading of buses built before April 1977 when stricter federal safety rules became effective; the flammability of seats; and the placement and protection of the fuel tank. The board will draft a report on the probable causes of the crash and make recommendations for avoiding similar accidents. The recommendations could be directed toward federal, state and local officials, as well as bus manufacturers, but the safety board has no power to require that any of them be implemented.