After a buzz by a passing municipal bus, I looked up the county department responsible and sent off this missive. I post in case anyone else has similar experiences and wants a template letter, and also if you have feedback as to my approach or wording, fire away. Thanks!
The Email I sent:

To Whom it May Concern,
I would like to document a bus driver (Ride On bus) who passed me, while I was on my bicycle, with about 1.5 feet-2 feet of space, inside the required 3 feet of passing space. If there is a department specifically for cyclist safety, please direct this enquiry there. Here are the details:

Bus number: 5031
Route Number: 59
Time/date: Approx 5:00pm today, Wednesday, May 20.
Location: Muddy Branch Rd, 1 block south of West Diamond Ave.
Incident: I was riding in the right lane of the two southbound lanes on Muddy Branch Rd. Driver passed me unsafely by passing within my lane and closer than the legal 3 feet of space.

I request that the driver, and all drivers (if not already standard training) be informed of the 3 feet passing rule and all code related to sharing the roads with bicycles. I am an experienced bike commuter and have taken bicycle safety and training courses through WABA (Washington Area Bicyclist Association). At the time of the incident, I was following all road rules and operating my bicycle vehicle in a safe and predictable manner; riding my bike in a straight course and at a steady pace. The driver had space, time and opportunity to safely change lanes and pass me (I have a rear-view mirror and saw the driver approaching and could also clearly see the traffic pattern behind me) but chose to pass dangerously close. I appreciate your help in making the roads safer for all parties concerned.

Good email.

Nicely written.

That's exactly how a letter should be written. No expletives and very professional.

Also, be thankful that the title of this topic is "Buzzed by a Bus" and not "Hit by a Bus"!

Excellent letter! May I have your permission to paraphrase you when I send this picture to Toronto Transit?

heh, yeah, paraphrase away. Consider the non bus and route specific parts as donated to the public domain.

Well done (I'll be filing that letter away, in case I need it).

Thanks for sharing.

Let us know if you get a reply.

I would be shooting off at least one of those every week if 2ft was the threshold. Around here, buses are the worst at getting a little too close.

Very good. Congratulations on suppressing the rant I'm sure you wanted to write

Good letter. I will file it away for future reference. In my experiences, school buses are some of the worst offenders for passing too closely. I've had some of them pass me so closely that my elbow almost touched the side of the bus.

reminds me of a line of dialogue from a "Zoo Story" scene in acting class from 35 years ago:

"Pop...slapped into the front of a somewhat moving city omnibus,"

Ever since I've been cautious and always on the lookout for a "somewhat moving city omnibus".

Very well written. I particularly like it that you preemptively address any possible excuses that could be made for the driver's conduct (cyclist wobbling/weaving, traffic "forcing" bus (how do you force a bus?) into your lane, etc.). Please do let us know what response you get -- it's always helpful to see how various transit authorities handle these things.

I wrote a very similar letter to MBTA after a hectic couple of days where I had been perpetually buzzed, run off the road, and honked at by bus drivers (in several instances, it was the same driver). I also indicated that this type of behavior was why I stopped using the MBTA and continue to refuse to do so until they get their crap together (in much more polite language). Never heard back. Shocking, I know. I'm sure the MBTA has far better things to do ... like texting.

Very well written. Hopefully you'll get a better response than I did after a metrobus forced me into a curb (while I was pounding on the side of it, and could hear passengers yelling at the driver to stop.) I got a form letter telling me about how much training the metrobus drivers receive, blah blah blah. Basically a statement of "What? Our drivers? No... nobody on our staff would do that."

I'm sorry to hear of your bad experiences guys I drive transit (company will remain nameless) and I always give a wide birth to cyclists. Were I work there is reminders it seems like every month to give cyclists plenty of room.

Just wanted to let you all know that most of us drivers aren't lunatics with a grudge against cyclist. Sorry for the few who are giving the rest of us a bad wrap.

No malice directed towards you. I just wish the bus drivers around here could get pounded into their heads: "Change lanes completely when approaching a cyclist, and don't merge back until you have completely passed the cyclist. Your bus is too big to safely fit in the lane with the cyclist."

It's the same old story though. They don't want to slow down to wait for an appropriate opening to change lanes, so they squeeze in where they can.

Classic. I take it that's a bike lane he's blocking?

Great e-mail. Thanks for sharing. Part of my commute shares roads with Metrobuses and Alexandria's DASH buses, so I've squirreled your well-worded message away as a template, should [knock on wood] it ever become necessary to send such a letter myself. While I hope it doesn't ever prove necessary, I have a sneaking suspicion it will some day...

I'll spare you my thoughts on stereotypical MD drivers vis-a-vis those of DC and VA, although they'd probably be fitting given this was a Ride On bus.

There isn't anything that makes me more nervous to know I'm on a bus route and see a bus in my mirror, especially when a stop is coming up. They're so long and wide, stop frequently, and the driver is often stressed about getting to his stops on time so I have zero expectations that they change lanes to pass only to move back over to the curb 1/4 of a mile up ahead to drop off/pickup riders.

They pass, I catch up, they pass I catch up... CURSE YOU BUSSES AND YOUR NECESSITY!

Here where I live and ride, I'm pretty sure buzzing cyclists is a "sport' among bus drivers. They actually seem to wait on you, and then try to take you out. Happens easily several times a week. Just yesterday, a bus sitting at a stop sign waited... no cars were in front of me, I was travelling at about 20-22mph and just as I got to within about 50' of where he was waiting, he pulled out and took as wide a turn as he could, leaving me no option but to basically stop. He saw me, he was looking right at me. I'd really like to infiltrate their driver meetings to find out how loud the chuckles are when they compare stories.

Unless you drive the Metro 232 in Redmond, WA, I've got no problems with ya. I actually had a chance to try driving a Greyhound bus through a cone-course once... you don't want me driving a bus. It's no easy feat. I can't imagine trying to drive one of the double-long articulateds that Seattle Metro has.

Sometimes, the cause is not even with the drivers. My last fight with the Bus operating company on Oahu, was caused by the company setting an unrealistic schedule and then supervisors jumping on the drivers for not maintaining the impossible schedule. That caused too many drivers to make bad decisions, for fear of losing their jobs. Sadly the operating company blew me off, even with my warning that they would soon hurt or kill someone. The next day a driver ran over one of their own customers. The operating company began listening to me, as I promised to testify on behalf of the injured woman.

So, in my last case, my fight with the operating company, ended up also helping out the bus drivers, by taking away the unreasonable pressure to maintain the impossible schedule.

This is a big problem. The riders get mad when the bus is late, bikes get squashed. It amazes me it doen't happen more often.

The 70A used to buzz me just about every day on my ride in to work. I think it was the same driver - but it doesn't seem to happen so much anymore. Either way - god I hate the MBTA.

The MBTA's customers hate it much more than we ever could ;-) Did you hear about today's power failure? Whole subway system shut down for half an hour during rush hour.

Great letter. I have sent similar emails to MBTA here in the Boston area and gotten a relatively positive response- or at least a "we'll look into and inform the driver".

To balance the scales a bit. I have also written letters praising those drivers that give me or other cyclists proper space and respect.

Positive reinforcement can have at least a noticeable effect as criticism at times. I also have written to the agency which oversees maintenance of the bike path and given lots of positive reinforcement every time they plow the bike path in a timely and effective manner. That way when my emails of "disappointment" come they seem to take them seriously. I have noticed some improvement to the plowing but, of course, that could be coincidental.