In many cases the at-fault driver is charged with DWI or other intoxicated-related offense. You can use a police report and investigation to show intoxication. However, not all drunk driving accidents are properly investigated by police officers or even investigated for intoxication. Nonetheless, other evidence can prove intoxication, such as eyewitness accounts of erratic driving by the drunk driver. Lay witnesses can testify to knowledge of the driver drinking earlier in the day, as well as observations about the driver’s balance, motor skills, slurred speech, bloodshot eyes, erratic driving, smell of alcohol, and other relevant factors. Granted, it is always better to have a trained police officer testify than a lay witness, but testimony by an eyewitness about what they observed concerning the drunk driver is admissible for a jury to consider.