Tunnel tension: To slow or not to slow
Add Axios as your preferred source to
see more of our stories on Google.
How yinzers act when they see a tunnel. Illustration: Aïda Amer/Axios
Let's talk about a classic Pittsburgh nightmare: tunnel traffic.
Why it matters: Overall congestion in the region isn't terrible, but every yinzer dreads getting stuck in gridlock that ends at one of our highway tunnels.
The intrigue: As frustration grows, many say the traffic is caused by drivers irrationally slowing down when approaching the tunnels.
Friction point: The yinzer consensus led Ryan and Chrissy into a fervid argument this month while drinking Super Punch.
- Ryan said it's natural to slow down when approaching tunnels, and with the bevy of on- and off-ramps that surround them, it's prudent to be cautious.
- Chrissy doesn't fear the tunnel monster and said slamming the brakes on the Parkway is a fast track to collisions, road rage and avoidable delays.
Slow dahn!
Decelerating makes sense when the road narrows and drivers' sightlines shrink, said Karen Lightman, executive director of Safety 21 out of CMU.
"Human behavior when the road is more narrow than before is to slow down," she said. "Drivers slow down when there is a fear they might hit other cars or objects, like tunnel walls or barriers."
Zoom in: Lightman added that many SUVs and trucks have grown wider over the years, which means many drivers are closer to hitting the walls or other cars in the tunnels.
- Pittsburghers also aren't great at zipper merging, and tend to get over before they need to, which causes more congestion, Lightman said.
Between the lines: The region's tunnels are surrounded by other merge points that always slow drivers down.
- The Fort Pitt Bridge's exit merges are often the fodder for memes because they're so hectic.
Maintain speed!
Sudden slowdowns don't just kill flow — they cause erratic lane changes and lead to more crashes, Pennsylvania's Department of Transportation said in a statement.
Context: PennDOT has tried everything over the years to keep drivers moving through tunnels — raising speed limits, adding brighter lights, and even lifting a ceiling.
What they're saying: PennDOT says turning the highway into a parking lot isn't any safer than maintaining the speed limit.
- "Slower speeds approaching the tunnel reduces the capacity, causing additional backups that contribute to back of the traffic queue rear-end crashes."
Zoom out: Unfortunately for those in the "keep it moving" camp, tunnel stoppage seems all but certain. One key reason? The lack of a shoulder, says Aleksandar Stevanovic, a professor at Pitt's Swanson School of Engineering.
- "I don't think people appreciate how important the existence of a shoulder is for people to feel comfortable when they drive," he says, likening it to construction zones.
The bottom line: Don't expect tunnel congestion to ease up anytime soon.
- Your best bet? Take alternate routes when possible, leave early, pack some patience, and embrace the zipper merge.