Really? My understanding was that the signal is a request to the vehicles behind you in that lane to yield and create space to let you in. That's how I always s

Really? My understanding was that the signal is a request to the vehicles behind you in that lane to yield and create space to let you in. That's how I always see it working here in Vancouver and it's a good system. People are very good about creating space in front of them when someone needs to be let in. Edit: This depends a lot on context. The relative speeds of the two lanes, whether there's a merge, and so forth. If there already had to be enough space to safely change lanes without any other cars slowing down or reacting at all, then turn signals would become unnecessary. Often there's an opening, but to really make it safe the car behind you in your target lane does need to yield to make it safe, and the turn signal is a request that they do so (or at least not speed up).