Beginning in the late 1930s, a policy guide for designing highways was published under the name A Policy for Geometric Design of Highways and Streets. However, individual states must adopt these policies, as there is no federal mandate for highway design. The book is referred to as the Green Book within the industry and includes suggested dimensions for medians, width of traffic lanes, turning radius information, width of shoulder, and suggestions for unobtrusive areas.
Highway design is planned and evaluated during three different phases:
1. During initial construction
2. During reconstruction
3. While resurfacing and restoring the highway
Basic Function of Highway Design
Highway design is intended to handle traffic in an efficient manner and minimize accidents. In designing a highway, the first consideration is the purpose of the highway. There are three basic functions of a highway:
1. Arterial: Longer stretches of roadway with travels traditionally moving at maximum recommended speeds
2. Collector: A road that facilitates traffic between local highways and arterial highways
3. Local: Anything not classified at a collector or arterial, usually not providing thoroughfare access.
However, functions of roads can change and this can lead to problems for travelers when the road’s initial reason for construction changes.
Proper highway design should avoid the following, as these can lead to defective highway design and potential accidents and injury:
1. Sudden changes in road speed
2. Short transitions in roadway cross section
3. Narrow lanes, shoulders or bridges
4. Ingress and egress areas with limited sight
Highway Design Defect
Faulty road construction is one form of a highway defect. This could involve the design or material used in the construction. Inappropriate, nonexistent or misleading road signs are another form of highway defects. In addition, improper design of construction areas is another highway design defect and a common cause for accidents.
Highway Design Failure
Highway design may fail in numerous ways including:
Faulty Construction: In addition to defective materials, this category includes design issues, especially those which could have been anticipated.
Signage: This highway defect could include missing signs or those that have not been properly maintained. Cantilever signs are prevalent on most highways. These signs have a pole on the side of the road and the sign hangs above the actual highway. Unfortunately, there is no federal mandate to inspect these road signs at regular intervals.
Construction Area: Highways seem to be perpetually under construction. It is the highway designers’ responsibility to properly identify the construction area and make necessary accommodations for roadway traffic including construction zones and rolling road blocks.
Pavement drop-offs in construction zones account for 160 deaths and 11,000 injuries per year. These accidents are preventable with proper signage and planning. Many highways and bridges across the county are in disrepair. In Massachusetts, over half of the bridges in the state are “structurally deficient or functionally obsolete.”
In 2008, a cantilever sign fell on 1-65 in Tennessee. There was no obvious reason for the sign to fall. Unfortunately, the sign had not been inspected on a regular basis.
In 2007, a rolling roadblock in a construction zone in Florida was to blame for the death of an 11 year old boy. Instead of slowing down traffic, this roadblock abruptly stopped in a sight-impaired area on a bridge which caused a chain reaction pileup.
Those involved in an accident related to defective highway design may be entitled to compensation for medical bills, pain and suffering. Injured parties may wish to file a lawsuit to seek damages, often due to the following issues:
1. Poor road design
2. Defective guard rails
3. Improper signs or misplaced construction alerts
4. Road drop offs
5. Faulty traffic signals
- Federal Highway Association (FHWA). (2009). Highway design standards. Retrieved from http://www.fhwa.dot.gov/environment/flex/ch02.htm
- Federal Highway Association (FHWA). (2009). Functional classification. Retrieved from http://www.fhwa.dot.gov/environment/flex/ch03.htm
- Federal Highway Association (FHWA). (2008, February 8). Federal lands highway project development and design manual: Chapter 8. Retrieved from http://www.wfl.fhwa.dot.gov/design/manual/Chapter_08.pdf
- Finley, J. (2008, July 8). TDOT to inspect signs after collapse: Collapsed sign last inspected in 2000. Retrieved from http://www.wsmv.com/news/16813368/detail.html
- McIntire, M. (2009, December 22). Efforts lag at making highway work zones safer. Pittsburgh Post Gazette. Retrieved from http://www.post-gazette.com/pg/09356/1022772-84.stm.
- Tedesco, W. (1998, October 2). Liability of state highway departments for defects in design, construction, and maintenance of bridges. Retrieved from http://pubsindex.trb.org/view.aspx?id=188902
- TRIP. (2008, June). Future mobility in Massachusetts: Meeting the state’s need for safe and efficient mobility. Retrieved from http://www.ma-smartgrowth.org/policy/FINAL_TRIP_report.pdf