Officers should drive defensively and safely when traveling to the scene, and upon arrival, park the patrol car in a visible spot to protect the scene, the persons involved in the accident, and oneself (the officer). Warning devices should be placed for oncoming traffic and a call for help made if it is needed to control traffic. A quick scene assessment should be made, which includes determining any injuries, providing first-aid, and calling for an ambulance and/or coroner. The officers check for hazardous materials, and establish a safe zone if needed. He should observe and collect evidence and inspect vehicles' exterior and interior for damage, unusual loading, seatbelt use, airbags, alcohol or other drug evidence, and possible vehicle defects. All information should verified, i.e., the identities of operators and owners, vehicle tags, and insurance; record observations and facts. If the crash occurred at night, the officer should go back during the next day to observe the scene and check for more evidence. The officer should have drivers exchange information and contact them if they recall additional information. The officer should not ask leading or misleading questions. Instead, general open-ended questions should be asked, such as, "What did you see?" If witnesses do not prepare a signed written statement at the scene, the officer should get their names, addresses, and phone numbers to schedule a follow-up interview. Photographs of any and all relevant evidence at the scene should be taken, such as skidmarks and the condition and location of the vehicles after the crash. Photographs should be taken before the scene is disturbed by the arrival of medical and rescue personnel or additional police officers. In the case of fatal accidents, the accident scene should be handled the same as a homicide scene, in that someone is dead, and someone caused that death.