Help! Question

My husband is a firefighter and works 24 hr shifts. I am 38w5d with our third child. Supposed to deliver via c section  10/23.  However if I go into labor before then I wanted to know what you all suggest I do.  Hubby works about an hour and half away.  If I do go into labor on my own how long should I wait call him  to have him start driving home. Until contractions are like 10mins apart?