Monday, September 9

I-10 & SH 46 In Boerne: 'Split Phase' Signal To Alleviate Backups

It was a tough call.

As part of our project on I-10 improvements between Scenic Loop Road and SH 46 in Boerne, our contractor (Texas Sterling Construction Company) has been steadily working on the retaining wall at the I-10 & SH 46 intersection, part of the work on that overpass and new turnaround bridges.

The tough part of this measure in terms of impact on the traveling public was that it had to take away the dedicated left-turn lane on northbound SH 46 at the overpass to get onto the I-10 westbound frontage road. That in turn created significant backups at the intersection and beyond.

That was the bad news -- now time for some good news. 

Even though it was temporary for this phase of construction, we determined the backups had to be addressed now and not left for later.

Hence the decision to bring back the northbound SH 46 dedicated left-turn option, using what our traffic folks call "split phasing." 

What does this mean? While the full dedicated left-turn lane still cannot be brought back, drivers at least will not have to keep waiting for their southbound counterparts to clear out before being able to turn. Instead, they'll have a protected turn arrow while southbound traffic waits for the light to change (see graphic for details).

The split-phase traffic light phasing change is being put in place today (Monday, September 9). 

As with just about everything else in traffic configurations, there's an upside and downside. In the case of this intersection, putting in place the protected turn arrow will of course give northbound SH 46 drivers better and quicker access to I-10 westbound. But it also means more overall delays as southbound SH 46 drivers will now have to wait their turn to go.

So again, it's all about give and take. We're hoping at least the overall flow at the intersection will improve with this move, resulting in great part from us taking public sentiment and input to heart.