In Austin too, and probably just caused a driver to think the same thing. They were in the left lane on a frontage road which was suddenly turning left even though there was an entire lane opposite the intersection blocked off by those plastic things that seem popular to randomly place in the road these days. I saw them hesitate and figured they wanted to merge right, so i decelerated a bit to add another car length or or so, at maybe 10-15mph. They had plenty of space, flipped on their blinker, and instead of just merging started slowing down, to which I decided I wasn't going to brake more to allow them to block myself and everyone else from rolling through the intersection. They basically stopped in their lane, and beeped as I rolled by, to which someone behind them beeped at them for blocking the lane.

In Austin if you want to merge, decide if you can, blink and then merge.

Don't expect people to stomp on their brakes and stop to let you in, especially if your already traveling slower than the lane you are trying to get into and decide to further slow yourself.

And if you can't merge, deal with it, exit, or miss your exit and go around. Next time you will be more prepared or you will learn how to properly merge.