It's not that easy. Poles vs trenches are a tradeoff discussion. FWIW I was once in construction digging trenches and I'm German, so I might be biased a bit.
Pro poles / open air:
- very, VERY cheap and fast to build out with GPON. That's how you got 1/1 GBit fiber in some piss poor village in the rural ditches of Romania.
- easy to get access when you need to do maintenance
Con poles / open air:
- it looks fucking ugly. Many a nice photo from Romania got some sort of half assed fiber cable on it.
- it's easy for drunk drivers, vandals (for the Americans: idiots shooting birds that rest on aboveground lines [1][2]), sabotage agents or moronic cable thieves to access and damage infrastructure
Pro trench digging:
- it's incredibly resilient. To take out electricity and power, you need a natural disaster at the scale of the infamous Ahrtal floods that ripped through bridges carrying cables and outright submerged and thus ruined district distribution networking rooms, but even the heaviest hailstorm doesn't give a fuck about cable that's buried. Drunk drivers are no concern, and so are cable thieves or terrorists.
- it looks way better, especially when local governments go and re-surface the roads afterwards
Cons trench digging:
- it's expensive, machinery and qualified staff are rare
- you usually need lots more bureaucracy with permits, traffic planning or what not else that's needed to dig a trench
- when something does happen below ground, it can be ... challenging to access the fault.
- in urban or even moderately settled areas, space below ground can be absurdly congested with existing infrastructure that necessitates a lot of manual excavation instead of machinery. Gas, water, sewers, long decommissioned pipe postal service lines, subways, low voltage power, high voltage power, other fiber providers, cable TV...
There's a huge downside to poles where I'm based: permit shenanigans by pole owners that delay projects and allow incumbents to destroy competitors. Granted, some municipalities do the same thing. One local municipality I have to deal with responds to permit requests almost instantly, while another takes weeks of pestering to acknowledge even the most basic of permit requests.
For anyone starting out today, I would strongly recommend having a planned legal / regulatory strategy to fall back on in the event that excessive delays occur by parties you cannot avoid dealing with.
Bell techs have done that and caused outages for customers a number of times. One outage ended up costing close to CAD$7900 to repair that they settled for due to it occurring on a weekend in a rural area during a snowstorm that required third party traffic control to meet the Book 7 requirements (on a weekend at the bottom of a hill in a snowstorm with insufficient visibility for us to work safely while doing a road crossing). Normally that would only be a $1k-2k or so, but traffic control, lack of slack due to the location of the cut and overtime for all parties involved really drove costs up. Less than 30 seconds with a pair of wire cutters can be downright brutal to repair if the conditions hit the worst case.
Meh, here in Germany you got the same issue with trenches. It takes ages to coordinate digging them, I think the worst example simmered for two years until the permits arrived. And then, it's a nightmare because you can't just cut off people's courtyards and parking spots for any time longer than absolutely required, so as soon as you're at depth you gotta cover the trench with steel plates so cars and pedestrians can cross...
those days it's not trench digging (unless it's next to highway with machine that in one pass will trench and lay conduit/cable), it's trench drilling with something like this https://www.ditchwitch.com/directional-drills/
frontier installed fiber in my area using this method. relatively quick and no damage that needs to be "aggressively" paved over.
Can't do that in a century old city street with century old utilities in it.
They dug up the sidewalk with shovels here as a result; though using machinery to move the soil they dug up and handle the asphalt that's covering the sidewalk along part of the street.
Yeah you can directionally drill across a front yard typically; but actual urban areas are just too filled with infrastructure.
before drilling there was a team that mapped and marked all underground utilities.
some of the drilling went between front yards (this is where underground vaults are/were), but a bunch was done below sidewalks and across the streets.
Pro poles / open air:
- very, VERY cheap and fast to build out with GPON. That's how you got 1/1 GBit fiber in some piss poor village in the rural ditches of Romania.
- easy to get access when you need to do maintenance
Con poles / open air:
- it looks fucking ugly. Many a nice photo from Romania got some sort of half assed fiber cable on it.
- it's easy for drunk drivers, vandals (for the Americans: idiots shooting birds that rest on aboveground lines [1][2]), sabotage agents or moronic cable thieves to access and damage infrastructure
Pro trench digging:
- it's incredibly resilient. To take out electricity and power, you need a natural disaster at the scale of the infamous Ahrtal floods that ripped through bridges carrying cables and outright submerged and thus ruined district distribution networking rooms, but even the heaviest hailstorm doesn't give a fuck about cable that's buried. Drunk drivers are no concern, and so are cable thieves or terrorists.
- it looks way better, especially when local governments go and re-surface the roads afterwards
Cons trench digging:
- it's expensive, machinery and qualified staff are rare
- you usually need lots more bureaucracy with permits, traffic planning or what not else that's needed to dig a trench
- when something does happen below ground, it can be ... challenging to access the fault.
- in urban or even moderately settled areas, space below ground can be absurdly congested with existing infrastructure that necessitates a lot of manual excavation instead of machinery. Gas, water, sewers, long decommissioned pipe postal service lines, subways, low voltage power, high voltage power, other fiber providers, cable TV...
[1] https://www.usgs.gov/news/national-news-release/illegal-shoo...
[2] https://ucs.net/node/513