How to Improve Bus Service
Bus schedules cannot be easily maintained on busy lines with short headways: Experience shows that buses offering this type of service usually arrive irregularly at their stops, often in bunches. Although transit agencies build slack into their schedules to alleviate this problem, their attempts often fail because practical amounts of slack cannot prevent large localized disruptions from spreading system-wide. This paper describes a more resilient control scheme that overcomes this problem. The method also produces even headways with less slack than the conventional approach. Thus, buses can run faster and be more productive.