I've seen these kinds of complaints a lot and the answer is always to use your best judgement when using google bike maps.

That said I like to look at it from google's/developer's perspective. How do you know which roads are good for biking on? Traffic and shoulder width are huge factors for cyclists, however, that data might not be in Google's database (for the shoulders at least).

This is a huge problem for us. How are you supposed to know which roads to take if you haven't been there before? When I went on tour I liked to ask people what the traffic is like on the route ahead. Usually the answer was: really bad. Having that information never changed my route though because my maps only showed one road so taking detours weren't possible (adventure cycling maps).

I don't think I could have done much better in most circumstances though. The worst roads are so bad because nobody has a choice when they need to get from point A to point B. You have to take road X.

I suspect that it's really bad in TX.