“…A distinct line of works has proposed the simultaneous optimization of the route network design, the frequency setting, and the timetabling problems (Yan et al, 2006;Zhao and Zeng, 2008). Other works, such as Furth and Wilson (1981); Gallo and Miele (2001); Peeters and Kroon (2001) and Ávila-Torres et al (2017), proposed the simultaneous optimization of bus frequencies and timetables. Contrary to the above, most works on timetable optimization, such as Sun et al (2015); Wang et al (2017) and Yu et al (2017), decouple the frequency settings problem from the timetabling problem and solve them in sequential order.…”