This page last updated February 16, 2024
Below are answers to some of the most common questions or complaints I get about San Antonio roads and freeways.
The following projects have FAQ sections on their own pages:
Road construction generally
- See the FAQ section on the TransGuide page.
- See the FAQ section on the HOV lanes page.
- See the FAQ section on the Loop 1604 page.
- Why aren't traffic signals in San Antonio synchronized?
Actually, most of them are. See the City of San Antonio's traffic signal management page for details and see this video to see it in action.
That said, if you're on a road and it doesn't seem like the signals are synchronized, here are some possible reasons why:
- You're traveling faster than the speed limit. Signals are synchronized for to allow a group of cars (a "platoon") moving at the speed limit of the roadway. If you're speeding and get out ahead of the platoon, you could arrive at the next signal when it's still red.
- You're traveling significantly slower than the speed limit (either because you're lollygagging or due to traffic.) If you fall behind the platoon, you could arrive at the next signal as it turns yellow or red.
- The road you're on intersects with another road where signals are synchronized. If the synchronization on one roadway conflicts with that on the other, then one will have to prevail over the other.
- You're headed in the opposite direction of the timing. Sometimes, signals on a roadway are only timed for traffic headed in one direction (i.e. the direction with the heaviest flow of traffic.)
- The traffic volumes on the road you're on exceed the capacity of the traffic signals. For a more in-depth explanation, see the related question in the FAQ on the Bandera Road page.
- Congestion in San Antonio could be solved by just timing the signals better.
This is a common assertion and can be true in some specific cases. But most of the time, it's way more complicated. At most busy intersections, there has to be sufficient green time for eight different movements on every cycle, so the signals can only be optimized so much before the laws of physics win. For example, the green time on road A could be extended to help clear out the backups that occur there, but that means the light will stay red longer for road B, which then increases the congestion there. If the green time for road B is then increased to ease those backups, that means the light will now stay red longer for road A and you're right back where you started. So as you can see, it's really not as easy as it sounds. Then scale that zero-sum complexity over an entire corridor and you see just how naive "just time the lights better" really is.
- If I'm at a red light and nobody is coming on the intersecting road, why doesn't the light turn green for me right away?
There are several reasons why this can happen:
- If the intersecting road has synchronized traffic signals, then your signal will have to wait for scheduled gaps in that "green wave" before it can change. When signals are synchronized, the green times on the major road are fixed by design and typically can't be preempted except for emergency vehicles.
- The minimum green time on the intersecting roadway hasn't yet expired. Whenever a signal turns green, there is a set minimum amount of time it will stay green. If a pedestrian signal has been activated, the minimum green time will usually be longer.
- Why don't they plan and build new roads before new developments are built?
This is answered in detail on the Why don't developers have to expand the roads first? page.
- What was the first freeway built in San Antonio?
The section of the lower level of I-10 (then just US 87) between Woodlawn and Culebra. It quietly opened in July 1949. See the San Antonio Freeways History page for a complete history of the freeway system.
- Why doesn't TxDOT upgrade Bandera Rd. through Leon Valley?
Since the late '80s, various upgrades to Bandera Rd. in that area have been proposed, including adding flyovers at major intersections and an elevated tollway, but the City of Leon Valley vetoed all of the plans on the belief that such upgrades would hurt local businesses by speeding traffic through the city (a serious fallacy in my opinion; congestion hurts businesses more than improved access would.) Fortunately, fresh leadership in recent years has resulted in a change to Leon Valley's official position and will hopefully result in much-needed improvements. See the Bandera Road proposals page for more details on current planning for that corridor.