Compared to other common transit modes such as light rail transit (LRT) or a mass rapid transit (MRT), bus rapid transit (BRT) bus service is attractive to transit authorities because it does not cost as much to establish and operate: no track needs to be laid, bus drivers typically require less training and a lower stipend as compared to rail operators, and bus maintenance is less complex than rail maintenance. Moreover, buses are more flexible than rail vehicles; a bus route can be altered, either temporarily or permanently, to meet changing demand or contend with adverse road conditions with comparatively little investment of resources.