As anyone who has ever written an online article, blog or posted to a social website knows, observing your readers responses to what you are writing can tell you a number of things. First, are people reading what I am writing? Second, are they interested enough in what I am writing that they want to hear more? When I wrote my series of articles on how to work with contours when building data, I was getting many questions and responses from readers. More so than any previous article that I had written up to that point. This confirmed, at least for me, a long time assumption that I have had: many (most?) data builders rely very heavily on contours for their work. Wanting to write a second series of articles that I thought would get the same response, I chose to tackle the most difficult aspect of data building: heavy highway. The opposite has now happened with this series of articles. There was little response and significantly fewer viewings. For me, this confirms another one of my assumptions: many (most?) data builders use contours as the basis for their work and either do not know how to, or do not want to bother with building a roadway from scratch and instead just use contours. Or maybe they have just grown tired of me rambling on. Yeah, its probably that after all. J

The desire to use contours should not come as a surprise as building heavy highway data is downright tough at times. Its not something you can learn to do quickly. Its something that takes years to learn, and years more to master. On the other hand, working with contours is straight forward and easy to learn and to teach. However, as I have said many times before, most, if not all, projects can not be properly defined by contours alone. Especially roadways. If a project design has plan and profile information in it and you are building it off of contours, you are making a very critical mistake that *will* cause numerous issues in the field. As data builders, our job is to recreate the engineers design. Not approximate it. Not roughly represent it. You are not doing a take-off. You can not built data like you build a take-off. You *must* recreate the engineers design. Perfectly. Unless these are the only things you have to work with, contours are not going to do that for you, especially not for a heavy highway.

Up to this point, my series of articles on heavy highways has covered all the preliminary steps of highway data building. Setting up your HAL's, drawing your VAL's, enduring super elevations, defining edges or hinges of your roadway and establishing your typical sections. It is now finally time to reap the fruits of your labor. With all these components finished, we can now start to lay down our roadway portions. As long as everything was setup correctly and consistently, your roadway sections will be not only correct, but exact. Unlike a parking lot where there is quite a bit of wiggle room for what a grade is at any given location, you mathematically know the exact elevation for a properly defined highway at any exact location. Using your software's roadway building system, you have now recreated the engineer’s roadway. This is the payoff of all your previous efforts. Now its time to clean it up and ship it out.

If you look at your typical heavy highway, you most likely have a mainline with a number of ramps and perhaps a few side-roads. In this case, by this point you would have built a unique roadway for each one. Once you allow your software to actually build them, there are obviously going to be areas which are not correct. For a heavy highway, these areas are going to be the gore transition (paved area between a ramp and the mainline, until the two separate) and any intersections. Outside of a few very, very rare circumstances, these areas are going to need to be built by hand - so don't go crazy with detail or time for these areas in your roadway manager. Once the roadway has been built in the software, simply trim back and/or delete the areas that are not correct. For an intersection, I will clip it back to the PC/PT of the curb return. For a gore point, I will trim back the paved shoulder to where the ramp and mainline shoulders intersect. While there is still some touch up to do with the paved surfaces, as long as you invested the correct amount of time in the previous steps, over 90% of your highway should be correct once you first put it down.

As for intersections, as I mentioned above we will want to build these by hand. Many times the engineer will provide intersection details in the plans. These will usually give you specific elevations and/or contours that define the intersection. If this is the case, then make sure you hit these. If you run into conflicts, you will need to resolve them on a case by case basis as sometimes it is better to go with the spot elevation from the intersection plan, and other times it is better to go with the elevation from the roadway plans. Just make sure there is a smooth transition and the water is going in the right direction. With the intersections done, continue to work through your project detailing out any other paved surfaces that could not be defined by your roadway template. As a rule of thumb, I always define and lock in my paved surfaces locations and elevations first, and them work through the rest of the project.

Now that your paved surfaces are completed, its time for everything else. Depending on your clients needs, you may even be done here as they are working with driving lanes only. Or perhaps your client only wants a subgrade model of the highway. In this situation you would just need to take your work out to the subgrade daylight. When this is the case, I will build a finish grade model first and then use a subgrade template to accurately define the subgrade daylight location. Remember, in super elevations or changes in the recovery slope, this location is going to move around a bit. If your highway includes detention basins, unique ditches, retaining walls or anything else that could not be defined by a roadway template, you will need to now grade them by hand using whatever resources you have. You may have contours, or cross sections, or spot elevations or a combination of sources. Regardless of where you get your information from, if your client needs these areas, you need to get them in correctly and accurately.

As long as you have done everything correctly, you have now recreated the engineers design - exactly. Due to their nature of design, you can be assured that your design is exactly the same for any location the engineer provided plan, profile and a typical section for. This is an assurance that can never come from contours alone. While it certainly will take more time than just converting contours, building a roadway properly will pay off huge dividends because your work is complete and correct. The longer that GPS is used for construction, and the more widely it is used, we will see a much more defined role of data builders throughout the industry. As that time comes closer, the ability to properly build roadways within your software will become a huge selling point and even a requirement for the best data building jobs. If you do not currently know how to do so, learn it as soon as possible. It will be a selling point for your services for years to come. And even more important, it will ensure that your services are correct, complete and above all else, accurate.