The city of Bangor is considering a series of changes to improve the safety along a busy section of Broadway where drivers exit from and enter Interstate 95, a short corridor a fifth of a mile long that has seen dozens of crashes in recent years. An outside engineering firm has recommended relocating an Interstate 95 on-ramp and remaking how drivers can reach two residential roads from Broadway, changes meant to minimize the chances of vehicles crashing into each other or gumming up traffic.