Week 4: Experimenting on Signal Timing

This week, I got into the actual Synchro files that Wells + Associates used for the BASIS intersection study. The model was already built, so I spent time figuring out how it was set up and trying some basic experiments with the signal timing. I changed the cycle length from the original to 120 seconds to see what would happen to the level of service. The results were interesting but also confusing because some of the delay calculations started throwing errors, which means I probably messed up the phase timing somewhere.

I also experimented with changing some of the left turn movements from permissive to protected. The eastbound left turn into the school is in a shared lane with through traffic, which means if someone’s waiting to turn left, they’re blocking everyone behind them. I thought making it protected would help, but when I ran the analysis, the LOS actually got worse in some places. I’m still trying to figure out exactly why that happened and whether it’s a timing issue or if I assigned the phases wrong.

Right now, I’m out of town on break, so I’m not actively working on the model. When I get back, I need to go through the original configuration more carefully and understand what Wells + Associates actually recommended before I start changing things. I think I was making changes without fully understanding how the ring and barrier system works, which is probably why I kept getting errors. Next week, I’ll reset and approach it more systematically.