As you mentioned, @james put together a great post on how to generate a traffic map using Bing. But as James noted in the How To, Google doesn’t officially provide an option for overlaying traffic.
If I understand correctly, he may have just meant to literally search for “St Louis Traffic” on Google as one of the first things they display is an image snapshot of traffic in the area.
Which results in something like:
https://www.google.com/maps/vt/data=Cycy18z-lUgh-1BuD9iI-Wqmp6219wePy8Z_aMmLGyi21fYrZLafuV4_UuyWpI1TKXr0kkVwcFU1yqM7sG_wX1sdACY_pTWtVIorERuxsOGhrRrwOG-KNghYrRR3WD30NOhACFPDyklbuJJCS2FrcUPx2eR9mCb5ZdJHa4tAy95gsSCt1O00pumGkH_h0Hm3FLoFKxjT7ivAP_XpakBTLFhLMgm1KaSbEhhowBru2czzLhm8FMTH3mmSmThpxLEUt7PpXRYDS9RnWcj5Wxg
I’m not sure how long these URLs last, if they’re actually ‘live’, their usage rights or anything though… but that’s how I interpreted the other person’s suggestion.