^^RSBM
I have to disagree that the intersection at East Austin & Magnolia Ave (i.e., Hwy 183 or turning southbound -- Hwy 80 & Interstate-10 interchange) is not a busy intersection to catch one's eye. I think there are several clues here that would catch your eye as you approach this intersection:
First, if you are traveling the San Marcos Highway (i.e., Hwy 80) to Luling, that intersection at East Austin and 183 is probably only the third or fourth traffic light in 23 miles after leaving the city limits of San Marcos (passing through Martindale, and Prairie Lea before arriving at Luling).
Second, the speed limit decreases significantly approaching this intersection beginning first with an approaching school, followed by the traffic light where the posted speed limit here is only 30 MPH.
Third, the traffic light is also very well-appointed with signage directing traffic to either 183 and/or alerting motorists to turn right for the I-10 interchange or to continue on with Hwy 80.
It further appears that the traffic signal may also have a mounted traffic camera.
If anything, I think passing the intersection -- especially without noticing the directional roadway signage would seem more like you're taking a detour when East Austin narrows as you cross the road, and it's evident you've entered a truck route, and definitely not continuing on the San Marcos Highway. Within a few blocks, the road forks and East Austin becomes Spruce Ave, and Spruce Ave eventually becomes Salt Flat Road.
It also doesn't follow that you'd even need a navigational app if your journey home requires travel on only two roadways: TX 80 and I-10.
MOO
Google Maps