I fantasize honking a horn at them but yeah I don't want to get shot either.

DC has great public transit so

1. You probably didn't need to bring your car. Also, the speed limit can be pretty low in certain areas so in many cases it's better to be riding an ebike or scooter, and ebikes and scooters don't cost like $14k/year.
2. DC has great public transit so generally the expectation is that people will get home on their own. Expected social dynamic is that people get home on their own. Uber can be expensive but Metro is $2-6 one-way. People are tripping if they can't afford $2-6. I'm assuming here that your friends aren't particularly poor or anything though. The main exception to the expectation I mentioned is places that aren't Metrorail and Metrobus accessible.

It's the reason they avoided giving tickets for fare evasion on Metro. It was seen as creating an inequitable environment.

My recommendation? Just run and do your best to be aware and assume that drivers are not paying attention.

I wouldn't recommend starting a fight. Someone might be bigger or stronger than you or have a gun. It's not going to make a difference. It's like walking into an open office and telling people to shut up. It's a waste of your energy.

As stated, enforcement only goes so far. You really need roads to be designed to make dangerous driving difficult. This includes speed bumps and narrow roads. Dutch roads are designed like this.