By Tim Willert Staff Writer twillert@oklahoman.comOklahoma City Public Schools is experiencing a high number of operations-related vacancies that are affecting the district's ability to address issues that include bus service, The Oklahoman has learned. "The district currently has a lot of vacancies in operations which is unfortunately resulting in a lot of frustrations across the district because it causes delays in our response time to school issues and issues with getting students to school and home on time," Superintendent Aurora Lora said in an email sent Friday to principals, assistant principals and district administrators. Lora told principals the district is short on bus drivers and will need to replace 20 teachers who are resigning at the semester break, which begins Dec.Read more on NewsOK.com