Streets around the United Center and McCormick Place will close, access around the sites will be restricted and CTA riders could see changes when the Democratic National Convention comes to town. Security and transportation plans came into sharper focus Thursday, when DNC officials unveiled measures that will limit movement through the area around the two primary convention sites as an expected tens of thousands of visitors, delegates, politicians and protesters arrive in Chicago. CTA President Dorval Carter separately answered questions from aldermen about how the beleaguered agency would balance transporting official convention participants and getting Chicago residents about their daily business. The picture that emerged was of plans with implications for drivers, ride-share passengers, food delivery services, cyclists and CTA riders in the days before and during the Aug.