Signal light debate: tower crane or mobile crane - which one takes priority?

I was on a job site in Phoenix a few months back and had a near miss with a mobile crane operator who didn't give way when I was slewing. He said his signal light was on, but I thought tower cranes always had priority. How do you guys handle that situation when both operators think they're in the right?

3 comments

3 Comments

wells.karen23h ago

Whoa hold up, that's a common mix-up but you've got it backwards. In my experience, mobile cranes almost always have the right of way over tower cranes, not the other way around. The reasoning is that a tower crane operator has a fixed, limited swing radius and can see the whole site from above, so they should be able to stop or slow down easier. A mobile crane has less visibility and more ground hazards to deal with, so they need the priority to keep things moving safely. Your mileage may vary depending on local rules, but every site I've worked on that follows OSHA standards gives the nod to the mobile crane operator unless they've got a specific agreement otherwise. That near miss you had sounds like the mobile guy was actually following standard protocol, and the tower op might need a refresher on priority rules.

kim.zara21h ago

Another thing nobody brings up is that mobile cranes usually have a spotter on the ground, while tower cranes rely purely on radio communication, so the tower op should have an easier time coordinating the slowdown. That extra set of eyes on the mobile crane side shifts the whole safety dynamic in their favor.

umar5918h ago

Alright, let me play full devil's advocate here @wells.karen. That "limited swing radius" argument cuts both ways - a tower crane's fixed path means if a mobile crane wanders into its arc, the tower operator has zero room to dodge, so they should get priority to keep that load moving through their zone without having to second-guess every swing. Meanwhile, a mobile crane can actually reposition or adjust its path on the fly, which gives them more flexibility to yield without halting the whole lift. On every site I've run, we actually gave the right of way to the tower crane because their loads are usually heavier and higher risk if they have to brake suddenly. That near miss you mentioned sounds like a classic case where the mobile guy should have waited for a clear radio signal from the tower op, not the other way around. OSHA rules are vague on specific priority, so it really comes down to the site superintendent's call, and in my book, the crane with the most limited options gets the nod.