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Engineers and planners face a variety of challenges when planning and designing new roadways. Although many of these challenges apply to the widening and expansion of existing roads, certain obstacles are unique to roadways along new alignments. When planning for roadway design projects, it’s helpful to have a general understanding of potential barriers so delays, cost increases, and headaches may be minimized. Here are a few challenges to consider:
When determining the width of right-of-way needed for a new roadway, it’s essential to take into account the cross-section of the new roadway, new utilities, and possible accommodations for cyclists or pedestrians. It’s also valuable to consider additional right-of-way that may be needed as a buffer from existing residences or for a future widening. Purchasing additional right-of-way now can undoubtedly result in future cost savings. Also, when establishing the centerline of the new road, consideration should be given to the location of the centerline so that the project doesn’t create remnants of property that are not economically viable following the purchase of new right-of-way.
Connections to Surrounding Street, Rail, and Trail Systems
When planning for a new roadway to accommodate future streets and driveways, it is prudent to establish access management standards for these future connections. In some cases, to restrict crossing access, medians can be constructed with desirable spacing between median breaks. In other cases, it may require creating a standard that limits the spacing of future access points along the corridor, if no median is present. Since new intersections will be created at either end of the new roadway, and possibly at crossroads along the roadway, the proximity of these intersections to existing intersections should be taken into account when setting the alignment. Different types of intersections should be considered to provide the safest and most efficient alternative. When railroad crossings are necessary, early coordination should be initiated, since it may be necessary to close other rail crossings to permit the new one. Since this process tends to be slow, it’s beneficial to begin this coordination as soon as a crossing is considered.
Stream Crossings and Wetland Impacts
When selecting an alignment for a new roadway, the location of existing streams and wetlands will have a significant influence on the final decision. The cost of bridges versus culverts will need to be considered, and impacts to streams and wetlands will need to be coordinated and permitted by the US Army Corps of Engineers (USACE) and Federal Emergency Management Agency (FEMA), where applicable. In some cases, mitigation costs must be paid for these impacts. Streams that include FEMA regulated floodways and floodplains will need to be studied in detail, and the time and costs associated with this study and FEMA’s review may have a substantial effect on the schedule and budget of the project. Before selecting a project alignment, it’s often well worth the time and cost to perform a preliminary delineation of the streams and wetlands along the corridor so that these effects can be minimized or avoided.
In order to proceed with survey and design of the proposed roadway, access will be needed along the corridor. The following tasks may need to be completed to determine the feasibility of the alignment and the appropriate design for the roadway: topographic and property survey, field investigations for cultural resources and endangered species, delineation of streams and wetlands, geotechnical borings, and staking of the new road centerline for review in the field. Although Alabama law allows for professional land surveyors to access the property of others prior to purchase, there are conditions for what work that may be performed by the surveyors.
As a result, right of entry agreements with property owners may be necessary to complete the desired surveys and investigations. Denial of access to a property, as well as the time-consuming process of getting right of entry agreements, will cause significant delay to a project. By having conversations and negotiating right of entry agreements with affected property owners early in the process, much of this delay can be avoided. In some cases, it may become necessary to perform some surveys and investigations after the project right-of-way has been purchased.