One of the best parts of living in the Bay Area is a thing called Casual Carpool. Here’s how it works: in various parts of the East Bay (Berkeley, Oakland, etc.), there are designated Casual Carpool pick-up spots. You wait in line at the spot, and pretty soon a car will show up. You get in, wait for a third passenger, and head to San Francisco, where you’ll be dropped off at a designated spot in SOMA (South of Market, for non-Bay Area folk).

Before you start imagining serial killers picking up innocent victims, let me assure you that this is an entrenched culture here. People have been doing it for years. There’s even a strict etiquette.

The first few times I was a little giddy, stifling my giggles as I got into a complete stranger’s car, said “Good morning,” and looked out the window. It was pretty much everything I had been taught NOT to do. After the first few times, I was a pro.

The reason why people use Casual Carpool is, of course, convenience: it’s convenient for the driver, who gets to use the carpool lane on the Bay Bridge, avoiding upwards of an hour of traffic, and it’s convenient for the rider, who gets a fast, cheap ride across the Bay.

Before July 1, 2010, it was convenient for the driver for another way, too: people who used the carpool lane on the bridge didn’t have to pay the toll. Starting July 1, 2010, however, carpool drivers were charged $2.50 for the ride (compared to the normal $6).

The change definitely posed a quandary. Before drivers were charged for the toll, riders didn’t feel the need to pay the driver anything. Hey, he was driving across the Bridge anyway, right? I’m saving him the toll money and time!

After the change, it was a free for all. Some riders offered drivers $1 for the toll (my preferred method), and some didn’t. Some drivers refuse to even think about taking the toll, pretty much thinking that the saved time is worth more than the $1 payment (my favorite drivers).

Some people attach a passive-aggressive note on the seat with a cup, pretty much asking for a contribution, but not enforcing.

Then there’s the Old Lady in the Mercedes (I’ll call her OLIM for short). The first time I got in her car, she asked for a $1.25 contribution before my butt-cheeks hit the seat. Thankfully, I had exact change.

She ended up being a regular at my stop, and I ended up riding in her car three or four times. She changed the enforced payment to a $1, probably because people were fishing around for pennies at the bottom of their bags to get the needed 25 cents.

The last time I rode with OLIM was the most memorable. I got into the backseat (the first passenger can choose the front or back, and I generally ride in the back because I carry my computer and a gym bag), and we waited for the third passenger.

A pleasant young man got into the front seat after a few minutes, and said hello.

OLIM: “That will be a dollar.”

PYM (Pleasant Young Man): “Oh my goodness, I’m so sorry, I only have a $100 bill.”

Me in the back (MITB), thinking to myself, “OH SNAP!” as my jaw dropped.

OLIM: “That’s no problem. I have change. When we stop I’ll give it to you.”

PYM: “Um…OK.”

MITB: Jaw practically dragging on the beautiful Mercedes leather seats.

The drive across the Bay Bridge was long, silent, and awkward.

We got to the designated stop, and OLIM hopped out of the driver’s seat, went back to the trunk, and brought back $99 in change.

I guess there’s a reason she’s driving a Mercedes and I’m in a Honda.