The bigger question to me, is why doesn't the US do combined gas/electricy/... trenches accessible by manholes, like you can see in most northern European cities? Is it just economic shortsightedness or does it have to do with density (or rather US cities being the opposite of dense)?

(yes there are regulations on minimum distance between electricity and gas pipes, so these trenches have to be pretty big)

> Hmmm, how does the gas company afford to bury the gas pipes then ?

According to Wikipedia, pipelines tend to be buried because soil acts as a thermal insulator, thus reducing thermal fatigue and consequently maintenance costs.

Electricity isn't transported through pressurized pipes, thus it isn't subjected to the same constraints.

Actually, most existing underground transmission cables run through pressurized pipes full of oil. Look up HPFF; it's pretty wild.

Newer cables tend to be solid, though.

Overhead gas lines aren't an option.

Gas pipes are overhead in much of eastern europe.

Looks kind of odd to see the whole city covered in what looks like scaffolding, but it's actually gas pipes and supporting pipes going down to every house.

Gas mains, or just feeder pipes to individual buildings or neighborhoods?

Both. Not sure why they do it - perhaps because the ground is frozen? Or because an above ground gas pipe is easier to inspect and repair?