Because of family and my wife's job I am limited to a very specific search radius when looking for openings or companies/institutions with possible openings. I also want to turn in high quality applications as well as follow-up repeatedly with prospective employers during my search, so I don't want a lot of search results that are clearly too far away from home to be practical.

Given that I will be traveling by car with access to one major highway, and living in a city of roughly 90k people, is there a way ([rule of thumb](https://en.wikipedia.org/wiki/Rule_of_thumb)) that I can use to convert distance to commute time? (Disclaimer: I know this will depend greatly on things like geography and population density.) For example, does a 30 mile search radius roughly translate into a 1 hour round-trip commute, give or take?