Roads vary not only in their width and purpose but also in their form and height. For example, some people might wonder why residential roads are higher in the middle and lower at the curb. For this assignment, I took an in-depth look into the reasons behind asphalt designs in residential areas. The answer, however, is not entirely apparent since there are several important reasons behind this design.
The initial reason for such a slope is the water drainage. This method of asphalt layout not only prevents puddles from appearing but also ushers water towards storm drains, preventing most of the floods (“Transportation & storm water design manuals,” 2017). The exact angle depends on the number of lanes, although it usually does not exceed 2-3% (“Transportation & storm water design manuals,” 2017). Such an angle also makes underground vapors less harmful to the road surface (Virginia Asphalt Association, n.d.). Residential areas must be able to withstand weather conditions without taking any damage.
At the same time, this slope gives another advantage in design. Such a method allows heavyweight vehicles, such as school buses or garbage trucks, to utilize these roads with the required frequency without severely damaging them (Virginia Asphalt Association, n.d.). Their weight is transferred to the curb, discouraging road deformation towards the middle. Moreover, even a slightly uneven road serves as a natural barrier to speeding. Residential streets must be designed in such a way so they prevent high speed and do not accept high traffic (Virginia Asphalt Association, n.d.). Low traffic makes roads last longer without repair, reducing upkeep costs. In conclusion, there are several benefits of slightly elevated middle of residential roads, such as decreased wear rates, efficient drainage, and more pedestrian-friendly traffic.
References
Transportation & storm water design manuals. (2017). The City of San Diego. Web.
Virginia Asphalt Association. (n.d.). Residential street design. 2021, Web.