More than Metro Transit buses 25 percent of a typical transit agency’s bus drivers do not have regular work assignments. These reserve drivers cover work resulting from both planned and unplanned work assignment changes.
A dispatcher assigns planned open work to reserve drivers a day in advance, but unplanned work is assigned as it becomes available without knowledge of which pieces of work may become available later that day—giving rise to the challenging problem of online interval scheduling.
Making assignment decisions is a balancing act that requires choosing between reserve operators or regular operators receiving overtime pay. To help address this trade-off, U of M researchers designed an algorithm that increases the amount of work covered by same-day reserve drivers.