Turtle ta = new Turtle(a.pos, ang);
ta.move(minimumRoadLength*.9);
coords[0] = new Coordinate(ta.pos); //start point
coords[6] = coords[0]; //first element is also last
ta.turn(collisionGeometryAngle);
ta.move(length);
coords[1] = new Coordinate(ta.pos);
ta.angle = ang - 90;
ta.move(collisionGeometryWidth);
coords[5] = new Coordinate(ta.pos);