In the past, coming from Saltillo, I have driven the Hwy 40 truck route that goes north of Monterrey to Cadereyta. It is fast & smooth but seems quite a bit farther than route 40 that runs through south Monterrey. My GPS is recommending taking that south route. It has been 5 years since I have gone though Monterrey & I know improvements could have been made to this south route. This will be midday on Friday Sept 7. Any suggestions or recommendations on which road is better.