eli5 why are manhole covers in the middle of the road and not on the sidewalk?

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eli5 why are manhole covers in the middle of the road and not on the sidewalk?

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19 Answers

Anonymous 0 Comments

Other answer covers why they are in the middle of the road but in my large neighborhood we have manhole covers on the sidewalks. Our neighbor has it in front of his house. The same reasons apply.

Anonymous 0 Comments

Utility locations vary widely based on jurisdiction. There are pros and cons to each layout configuration. The major draw back from placing sanitary in the middle of the street has to do with it being under paving. You then need to be worried about getting proper placement and compaction of the trench. If this doesn’t happen you compromise the pavement. I’ve always preferred to do my sanitary designs with sanitary on the edge of row placed in an easement.

Anonymous 0 Comments

Yes. I meant plat – a term for an official document that shows the property line, all of the distances and directions of all of those lines and the precise amount of property contained within. This record is filed with (usually) the county or city that contains the property.

Anonymous 0 Comments

At some point that was the sidewalk. Like back when the city was getting the sewer, water, electricity…

Then, decades passed, people multiplied, bought more cars, and roads needed to be widened.

Anonymous 0 Comments

I think the city determines placement. The parents of a school friend had property they were developing. They made streets and service tunnels. All services had to be underground but power and communications were under the sidewalk with man holes on one side of the street. The pipes we’re about 24 inch across and had bunkers for the workers to access junctions for maintenance. Tees were installed for each property edge. Deeper were the water and sewer pipes capped at the property edge but down the middle of the road with manholes for the sewer. Storm drains were above the power then dipped down to a common drainage down the middle of the street and gas lines were the shallowest down one side of the street but installed by the gas company on one side of the street and teed off to the property edge.

Anonymous 0 Comments

Manhole covers are all over the place. Have you never seen a storm drain built into the sidewalk next to a road? Most of them have manhole covers on top so they can be unclogged when too much debris washes into them.

You think manhole covers are in the middle of the road and not on the sidewalk because of your confirmation bias: you only remember the ones that fit your foregone conclusion.

Anonymous 0 Comments

The manholes you see in the middle of the road are generally to access stormwater pipes. Roads generally slope very slightly from the center to each side to drain rainwater to the kerb. The water then gets collected by a drain, and makes it’s way through a small pipe to the main pipe in the center. This arrangement ( main pipe in center with small pipes connecting to the drains at the edges) makes it easier to design the pipes with the optimal slopes to drain rainwater. Also, as you have drains on each side of the road, rainwater moves more quickly from the road surface.

Manholes that you see on the pavement /sidewalks are generally to access utilities such as electricity, gas, and communications cables, as there is no reason to put them in the road. Access to pavement areas is easier for obvious reasons.

Ultimately, access points to utilities and stormwater drains are placed based on both easy access for maintenance and design / construction constraints.

Source: I’m a civil engineer

Anonymous 0 Comments

Wow, all these answers are kind of bad. Actual civil engineer here. There are many reasons, none really take precedence over any other. Sometimes manholes are in the sidewalk but not always. Here are some of the most common reasons. 1. The utilities need to be accessible and in the public right of way. Due to American construction the right of way always includes the road from curb to curb. It does not always include the sidewalk. 2. Space, underground utilities can turn into rats nests real quick. Take a look at a NYC cross section some time. Most companies try to separate their services from one and another but there is only so much space and a lot of things go under ground. The area under the sidewalk might have storm drainage under it, or electric, but that might mean their isn’t space for anything else. So maybe sanitary sewer and potable water need to go in the street.
3. Ada, this is a newish consideration (20-30) years now. Putting utility boxes and grates in the sidewalk is frowned on now because they can create triping hazards that can cause issues for accessibility and walkability.
4. It’s possible the utilities were under the sidewalk when they were originally built. But then they widened the road and now the new lanes are where the sidewalk was. 5. Landscaping (tree roots) can damage utilities. ain’t no landscaping in the middle of the road.
6. Access, utilities are serviced by vehicles and its a lot easier to block a lane of traffic for a few hours then to potentially need to go offroading with a maintenance vehicle or walk your equipment and material from your truck.

Anonymous 0 Comments

I work in utilities: manhole access to the sewer has to be a certain distance from each other, as well as at any change of direction in the sewer line. The reason they’re in the road and in alleyways (where you have them) is for access reasons. Checking flow up and downstream of problem areas for instance. Most sewer mains are centrally located for easier tapping for new service lines. In a lot of places, the street was there before the sidewalk was ever planned, so that’s where the Main is.

Anonymous 0 Comments

sometimes they are on the sidewalk. It’s less about being “in the middle of the road” and more about being where the underground pipes are.