The strike has suspended all regular routes starting Tuesday morning, but GET bus officials said those with severe medical needs will have transportation.
GET officials said they negotiated with union officials through the weekend but couldn't reach a deal.
Local 517 is asking for a 4% raise for each year of a three year agreement. GET bus officials said drivers make $14 to $22 an hour.
The union is also fighting for wages and benefit packages for part time employees. Union officials said the part time status doesn't necessarily reflect the number of hours part time employees work.
GET is offering work for employees who want to work Tuesday. The level of service will depend on the number of employees who show up for work.
"We are very aware of what this is doing to our customers. We've had a number of calls. I wish there was something that I could say to them. It is very unfortunate. It is our hope that the strike will be brief and that we will be able to provide service to them very quickly," said Gina Hayden the GET district spokesperson.
GET officials report about 20,000 boardings a day, which includes a person riding to and from a location.
More than six million people use the service annually.
GET officials said the last time there was a strike was in 1980. It lasted two months
More than 250 employees are expected to strike Tuesday.
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