So here's a practical question I faced the other night:
I was driving home from a shiur on Sunday evening; it was about 10:15 PM, and I was five minutes from home after a very long day. I was on a long, relatively busy street (heading north on Bathurst, just south of Steeles, for those who know Toronto). Two cars in front of me, a Toyota, some sort of SUV, stopped significantly short of the light. I thought it odd, but not unprecedented.
The light changed, and the SUVish vehicle started moving - not only forward, but also veering a little into the lane to its right, then back into its lane, and over to the oncoming traffic on its left side. Then far into its left, so that it nearly hit someone who was coming the other way in a turning lane - they missed colliding by perhaps five feet. Then they veered back into their lane.
So it went for the next couple of blocks, before I turned off of that street, as they continued.
To me, this was pretty clear evidence of an impaired driver. The veering was so consistent that it seemed more likely to be intoxication than texting or poor vision.
I imagined calling the police to give them the plate number and approximate location, but knowing that plenty of people get on and off that street at every light, and that I rarely see patrol cars in that area without a specific cause, I didn't think that it would accomplish anything.
I imagined staying behind that car - but to do what?
And so I did nothing, which isn't my usual approach to problems in a public space. Maybe it was just because I was very tired, from giving 3 shiurim that day, and writing up another 2 shiurim. But it's been bothering me. So my question is: What would you have done? What should I have done?