Thanks to everyone for their advice. I was actually turning right from a highway service road lane, not an intersection. There is a yield sign, not a stop sign. Here it is: http://maps.google.com/maps?hl=en&tab=wl I was going south on the service road beside the Clearview Highway and turning right onto Union Turnpike.
The way I was taught...many years ago and it may vary from state to state...is that it is illegal to change lanes when approaching or entering an intersection. Specifically because of this situation.
Pull up the location on google maps, then click "Link" on the right side, in the blue bar directly above the map. That will give you a hyperlink that will show us what you want.
Google Maps Ok. I think this works. I was driving south on the service road to the west of the Clearview and made a rt. turn onto Union Turnpike, from the lane curving right. There is a yield sign. Union Turnpike had 3 lanes in each direction.
It's not always that bad in practice though. As qbee mentioned many such places have the solid white line separator to prevent lane changes in critical merging sections. Another thing to remember is that you can still safely turn into a clear right lane with a smaller gap to the cars in the left lane than would otherwise be safe if it were only a single lane. What I mean is that if you were turning in to a single lane road with oncoming traffic at say 50 MPH then you need to wait for a large enough gap so that you can make the turn and accelerate to at least somewhere near 50 MPH before the oncoming traffic catches you, at least if you want to not inconvenience (or minimally inconvenience) the other traffic. Now if you've got two lanes oncoming but the right lane is clear then, even though you still have to give way, the situation is much better for you. Ok you still absolutely DONT want to pull out into what would be a direct collision course with an oncoming vehicle should they decide to change lanes just at that point. But at least you can now get away with a considerably smaller gap to the oncoming traffic than would have been desirable in the single lane situation. This time you don't really need a gap large enough to get fully up to speed, just large enough so that you are in the lane and accelerating before the traffic catches you. Because once you're in the lane, even though not up to speed, if a driver changes to that lane after this point then it's his bad luck, he's the one that has to slam on the brakes and wear it, and if he's so inattentive that he rear ends you then it's his fault. (remember that this is providing that you've completed the turn and are travelling straight in the lane before he actually changes lane). So this really lets you safely turn with a smaller gap, but you still need a gap!
Good advice. When I looked, the right lane was clear at that moment, but the cars in the center and left lane were coming on fast. I decided to go even without much gap, thinking the right lane was safe. At that very same time, the guy in the center lane decided to move right, just in order to pass. (New Yorkers have very little patience, including me). Luckily, he honked, I stopped and there was enough room for him to avoid me. The lesson is that you cannot assume the driver in the center lane will remain there. I like to learn from these incidents. If, on the other hand, I were the driver in the center lane, I would not have moved into the right lane, seeing someone at the yield.