Some Infected are found wearing blue shirts with the insignia of the Harran Police Department. Some are found carrying Police Batons, or nothing. They can be identified by their blue shirts with the insignia, and in rarer cases, a cap. They can be found in the Slums , but can be found more frequently in Sector 0 (Old Town).
Paramedics can be identified by their Yellow/Orange and Red uniform. They often wander near the Overpass, and near ambulances.
Tourists can often be identified by t-shirts which have their flag insignia on it, or are often found near buses. They aren't always easy to identify.
Runners can be identified with less difficulty. Runners are often Virals, and often wear jackets and runner equipment.
Some look like generic survivors wearing filtering masks, and jackets with tactical pouches. They are almost always Virals.
Hazmats are infected that have tried to control and contain the outbreak. They are presumably part of the police, or the military. They are harder to defeat, but their weakpoint is the tank on their back. But it can be a wise decision to take it head on - as the tank explosion can attract Virals.