It takes crews a bit to get there sometimes, it's not like they have trucks waiting on standby every 5th mile marker to scrape a dead bear out the road. Usually it's just the poor schmucks who happened to be nearby/the new guys on the crew with the particular highway dept whose jurisdiction it's in. Not to mention, they don't know it's there until it's reported...

Source: me, have been the poor schmuck/new guy on a highway dept crew