3B-2 Sign Shapes Sign shapes also indicates the sign's message. These signs warn you of special conditions or hazards ahead. Slow and proceed with caution. When vertical, signs are generally used to give instructions or tell you the law. When horizontal, signs give directions or information.
Signs indicate a no passing zone.
Signs indicate a railroad crossing. Look and listen for trains. These signs provide information about traffic laws. Obey their instructions. NO -the symbol indicates what is prohibited.