A flashing red signal means:

Like a stop sign, a red flashing light at an intersection means that you must come to a complete stop before entering the intersection. If you are facing a red flashing light at an intersection at which cross traffic is not required to stop, you may proceed only when the intersection is clear and when you will not interfere with the right-of-way of cross traffic.

• Slow down.
• The same thing as a stop sign.
• Caution, there may be danger.
• Look both ways and then proceed.