Hello,
Global turns are never automatically generated. I think what you want is a default turn penalty imposed upon, for example, your DriveTime attribute. To do this, open the network dataset properties, select the attribute on the Attributes tab, and click Evaluators... On the Default Values tab, select the Turn row, and for Type, select Global Turn Delay. Then click the properties button to set the various time delays.
Then at solve time when transitioning between two edges in the network, these delays will be included.
If you have explicit turn features added at these pairs of two edges, these will take precedence and override the default delay.
Let us know if you still need help.
Jeff