How long does it take to build a road?

Answer 1

Depends upon the municipality and/or region where the road is to be built. Also must take into consideration the length of the road to be built, any rights of way that must be dealt with if the roadway needs to encroach other peoples property.

Also depends on the contractor and how many people they assign to a particular task or job.

Answer 2

I've worked on dirt crews asphalt paving crews, and curb and gutter crews... what I know about the subject of road building could constitute a few books worth of information. There are aspects of road building I haven't been involved in, also, and what I don't know could fill volumes more. I'm going to try giving you an abridged version here.
First off, I'm going to say that there is no definitive answer to your question, as we don't know the things which factor into it - type of road, type of earth it's being built on, anticipated weather concerns, width and length of the road, etc. There simply isn't enough information to even begin to try answering your question. But I can explain some of what goes into it, if you're interested.
If you're building a new road completely from scratch, the first step is going to be engineering. They have to engineer with a mind towards things such as noise control, drainage control, etc. Before a blade so much as touches the soil, there's a couple years of that invested already.
Then there'll be clearing... how much, depends on what needs to be cleared... bare earth without too much vegetation will typically be quicker than dense forest, all other things being equal. In the case of the latter, the forest will be commercially logged, because, after all, waste not, want not.
Then the surface of the road has to be given a rough grade and fill to fit the contour desired for the road. How long this takes depends on a number of things, such as density of the earth being graded, weather conditions, and overall width and length of the road.
Then a rough cut will be made to form the basis of the road shape and contour. If utilities are going to be run under the road, then a lot of this work will be done during this time.
At this point, you'll see your curb and gutter crews come in if they're building curbing and sidewalks alongside it. They'll go through a similar process as the dirt crew, figure out the contour of the curbing and where the top back of curb (TBC) should be, they'll make their cuts for the curb, put in their forms, pour the curb, and let it cure.
After that, the finishing (dirt) crew will come in and make their final grade.. how long this takes is also a variable... if they have to raise manhole and sewage covers and water valves (such as they do on residential roads), that factors in... if there's a lot of soft spots in the grade where the ground pumps under the weight of a vehicle, those will have to be dug up and refilled until it no longer does that..
Then the dirt crew will shoot hubs along the center of the roadway, and how high or shallow these hubs sit is going to depend on the depth of the road from the top back of curb (even on roads without curbing, TBC is still measured, and represented by stakes used in place of a curb)... so, if there's going to be four inches of asphalt and two inches of road base, the cut will be six inches, and then the grade will be factored in... no road is laid perfectly flat, and there'll always be a grade for drainage purposes. Where the hubs sit is a very precise thing, measured by laser, and the top of the hubs after they're set ultimately represents where the height of the crown in that road will be.
Once that's done, then comes the finishing grade, where dirt will be graded out or filled in as needed to bring the surface to the appropriate height and grade, the quarter crown is completely graded out, etc. Rollers will follow behind the grader to ensure the dirt is compacted. How long this takes really depends on the material they're working with.. really rocky dirty and soils infused with either cement powder or polymer tend to be much more difficult to cut.
Then, if there's road base to be laid on top of it (which could be limestone, ABC mix or processed fill, crushed bedrock, crushed concrete, asphalt millings, etc.), that'll be shipped in and graded... one that's graded and rolled out, then manhole covers, water valves, et. al will have to be raised again to be level with the grade of the road base.
At this point, the paving crew comes in.. asphalt is laid in layers... except in the case of small driveways, it's almost never laid out as a single, homogenous mat. How many layers and what type depends on the type of road and what type of mix they're using... a street in a residential subdivison - which will be generally lower and lighter traffic - might have two layers of surface mix, whereas an Interstate Highway is going to have layers of base, binder, and surface mix (and the latter will be a couple feet thick).
Once that's all said and done, then manhole covers, water valves, etc. have to be raised again, and a follow-on crew will level those with the road surface once the final layer is laid, and fill back in what they had to cut out in order to do so.
The final touches will be your road painting, signage, and guardrail crews... having never worked for any of those, I can't say what kind of productivity you can expect from them.
So, it all boils down to length of road, type of road, type of material the dirt crews are working with, weather, and also assets available to the crews... not all construction companies are created equal and the company which can dedicate one dirt or paving crew to a single project will have faster turnaround than a company which has to bounce those crews and assets between multiple projects.
People like to complain about how long roads take to build, and that really boils down to them simply having no idea of how much actually goes into building a road... there's a whole lot more to it than simply throwing down some asphalt and rolling it.