In most large cities in developingcountries, buses continue to be the public transport optionof choice, carrying a large share of urban travelers.However, transit bus companies in these countries are oftencash-strapped. In many cases, the operating cost per buskilometer exceeds revenues and bus fares are often kept lowirrespective of the cost of providing service. Many citiesare dominated by old and fuel-intensive buses with highoperating costs. Transit systems are also often plagued byovercrowded and undependable service, congested roadways andchaotic operating environments. Across the board, cityofficials in developing countries are under strong pressureto improve the efficiency and enhance the attractiveness ofbus transportation. Fuel makes up a relatively largefraction of total bus operating costs, especially when laborcosts are low, as in many developing countries. Fuel costscan be reduced by improving the driving style of bus driversand through sound maintenance practices. A safe andeconomical driving style can reduce variable costs, decreasedown time due to repair work and maintenance, mitigatenegative environmental impacts and improve road safety. Thisguidance note1 provides detailed and practicalrecommendations on how city bus operations managers andtheir technical staff can plan and implement suchenhancements to their fleets through Operations andMaintenance (O and M) practices without significant capitalinvestments. By implementing such recommendations, municipalofficials and bus operators can increase the efficiency andfuel economy of their bus systems and reduce theircities' energy consumption, congestion and pollution.This guidance note provides detailed and practicalrecommendations on how city bus operations managers andtheir technical staff can plan and implement suchenhancements to their fleets through O and M practiceswithout significant capital investments.