Ron , do you think they ran from you because your calling was off key or you implied the wrong thing to them . I doubt it very much .
I think those same turkeys are familiar with the traffic . Their familiarity with the traffic over time has become a daily or maybe a weekly experience without pressure . We don't really know just how many trucks stop where you did to watch or even call to the birds , now do we ?
Step over here a moment .
You or I could go out into a favorite feeding ground dressed in blue jeans and red plaid shirt . Find a good seat and sit down . Become very still and remain motionless and quiet . We may have to sit there a week or 10 days but those turkeys will be along . Sure they'll look you over but as long as you don't move or make any turkey sounds from your calls they will not spook . Over and over we read a story from deer hunters that were sitting in their stand and along comes a flock of turkeys and the turkeys paid no attention to the blaze orange blob in the tree . Now had this or probably most , if not all deer hunters that experience this would ease out a call and make a few yelps or such , I'd bet that those turkeys would leave in a hurry .
They see things very well . And grow accustom to some things like autos . But when a turkey sound comes from that auto ,,or tree stand ,,,or red plaid shirt , what do they see ?,,,not a turkey . This is why it is best to blend in with your surroundings when hunting , and make no calls when the turkey can see your position .
Many times my wife and I would be way off in the hills driving in places unseen by our eyes before that day . Eventually we'd spot a turkey somewhere . One particular bird comes to mind as I write this . A hen was feeding alone at around 250 yards from the road . I pulled over and shut off the engine . We sat there glassing the ol' girl for quite a while without her showing any concern at all. Then I put in a mouthcall and made one series of keekee's . She stopped , looked our way for not quite one second and took to running hard ,,,,,away from us .
This goes along with that other thread about how well turkeys see and hear . If they hear it , they know where to look .