Write a friendly e-mail saying, that I won't be able to join todays meeting. Make up a very understandable reason, that's serious enough but won't lead to awkward questions from my coworkers tomorrow.
It is good to be honest to avoid later complications, but here goes.

Dear [Recipient],
Due to a transportation issue resulting from a feud with a berserker fringe element, I will not be at the meeting.
You can still reach me remotely if anything is critical.
It might be better to have someone else cover the tasks today though.

See you soon,
Rewrite the friendly e-mail with a different and nicer reason as to why I am unable to join today's meeting. This e-mail should be at least a paragraph long and at most, 2 paragraphs long.