@MassWineGuy just for your own benefit, I don't think you had your turn signal on for an "extended" amount of time. And, to correct you, if you were going 30mph, for 250' you would have only had your signal activated for about 5.7 seconds. It takes the average person .75 to 1.25 seconds to react once they see an action requiring input of steering or braking. Thanks for being a good motorist!
@falcon back see above...
Most of the motoring public that are, dare I say, "decent" drivers signal way before 100'. At 30 mph, you are traveling at 1.47 feet per second that gives the person behind you about 2.3 seconds to react and add input. 250' isn't bad at all.