The Boulder Valley School District says it wants to replace its diesel school buses with more environmentally friendly green buses. However, the district is going to buy five new diesel school buses because the electric and propane-powered buses won't hold up on the more demanding routes. The district is set to approve the purchase of five new diesel passenger school buses for $714,876. The district is expected to approve the new school buses at its Oct. 24 meeting. The district said the new diesel buses are needed because, "diesel school buses are essential for mountain routes due to their robust...