[hr0m]

I can confirm all of it for Germany as well (except the Italian serpentine road synchronization hack).

I flash lights for oncoming traffics because of danger or police checks.

I flash warning lights (or raise right hand) for thank you. Others do as well (especially buses, when you let them out of the bus stop, since in Germany they don't have the right of passage leaving a bus stop)

I learned that truck drivers (and buses) flash left, when it's not safe to overtake.

There are also some official rules regarding bus flashing at a bus stop (right, warning). But most of drivers ignore that.

[kriro]

I'm pretty sure I learned that if a bus has the blinker on when leaving the bus stop you are supposed to let them into traffic. A quick check seems to confirm it (§20/5 StVO).

[paledot]

Here in Montreal the buses leave the right signal on while stopped at a stop, then activate the left signal as soon as the doors close, even if they're in a bus lane that they don't intend to leave. To complicate matters further, they use the hazard lights while stopped at a timing point, so you can't tell just by looking at the left side if the bus is about to merge or if it's going to be stationary for the next 10 minutes.

Parts of this make sense, and I appreciate the consistency, but the execution leaves something to be desired.

[Aissen]

Somewhat tangentially related, but the french government did an interesting ad on this (very entrenched in France too) habit of flashing lights after police checks: https://www.youtube.com/watch?v=VNsVZu-2IaA

[fho]

It's somewhat common among truck drivers in Germany to flash the turn signals left-right-left-right to say "thank you" after overtaking (another truck).

[sva_]

I think it's usually right-left-right-left.

[matja]

Maybe it's the other way when driving on the left? :)

[hengheng]

Is that saying thanks? I thought they were just fumbling with the blinker control.

[YeahThisIsMe]

It's saying thanks as a response to the slower truck flashing its high beams to let the faster truck know it's now safe to move back over to the slower lane.

[londons_explore]

yes, that's saying thanks. It's equivalent to the hazard lights, but in some vehicles the hazard lights button isn't very accessible.

[matsemann]

> I flash lights for oncoming traffics because of danger or /police checks/.

Why? Do you want dangerous drivers on the roads?

[throwaway0a5e]

Attitudes like yours are what embolden governments to engage in revenue enforcement the proliferation of which leads to people tipping each other off about said revenue enforcement (e.g. flashing their lights to warn of speed traps). People wouldn't be warning each other about the cops if "people the cops shake down" and "people who were doing dangerous things just prior to being shook down" had more overlap.

[Dayshine]

I'm not sure I understand your point, unless you're arguing that national speed limits are deliberately low so that police can fine people driving at the "correct" speed? Or that police lie about your speed and fine you anyway?

[Firehawke]

The former is definitely true. There are towns out there in the United States that are on an interstate and play games with their speed limits. You'll see a speed limit of 60-70 up until you hit city limits then it suddenly drops to 30-40, with enforcement lined up at the city limits waiting to nab people.

They're making good money off of these fines.

[Dma54rhs]

But why wouldn't you want lower speed inside the city?

[Firehawke]

You normally would, but this is just predation on through traffic. It's not like you're going through the middle of main street, these may be off to the side of town with several exits but close enough for the city to dictate speed limits.

[niij]

Flashing lights is meant to communicate to others they need to slow down or otherwise obey the traffic laws. How does that have a negative effect on safety?