People with Autism

Speak calmly - use direct, concrete phrases with no more than one or two steps, or write brief instructions on a pad if the person can read.
Allow extra time for the person to respond.
The person may repeat what you have said, repeat the same phrase over and over, talk about topics unrelated to the situation, or have an unusual or monotone voice. This is their attempt to communicate, and is not meant to irritate you or be disrespectful.
Avoid using phrases that have more than one meaning such as "spread eagle" "knock it off" or "cut it out".
Visually check to see if there is a wrist or arm tattoo or bracelet that identifies the person as having an autism spectrum disorder.
Some people with autism don't show indications of pain - check for injuries.

Approach the person in a calm manner. Try not to appear threatening.
The person may not understand typical social rules, they may be dressed oddly, invade your space, prefer to be farther away from you than typical, or not make eye contact. It's best not to try and point out or change these behaviors unless it's absolutely necessary.
The person may also look at you at an odd angle, laugh or giggle inappropriately, or not seem to take the situation seriously. Do not interpret these behaviors as deceit or disrespect.
Because of the lack of social understanding, persons with autism spectrum disorders may display behaviors that are misinterpreted as evidence of drug abuse or psychosis, defiance or belligerence. Don't assume!

If possible, turn off sirens, lights, and remove canine partners. Attempt to find a quiet location for the person, especially if you need to talk with them.
Avoid touching the person, and if necessary, gesture or slowly guide the person.
If the person is showing obsessive or repetitive behaviors, or is fixated on a topic or object, try to avoid stopping these behaviors or taking the object away from them, unless there is risk to self or others.
Make sure that the person is away from potential hazards or dangers (busy streets, etc.) since they may not have a fear of danger.
Be alert to the possibility of outbursts, impulsive, or unexplained behavior. If the person is not harming themselves or others, wait until these behaviors subside.