Road Design Issues in Motor Vehicle Accidents


Although roadway design has improved significantly throughout the 19th century and through the present, errors in design and construction often still contribute to motor vehicle accidents. Road defect litigation can be very difficult due not only to the technical issues involved, but also due to the assertion of sovereign immunity by the governmental agencies responsible for the design and maintenance of the dangerous road or intersection.

How Road Design Can Contribute to Auto Accidents

Factors in road design that may contribute to the likelihood of an accident include:

  • Banking / Camber - When roads and highways curve, the outside edge of the curve is often raised such that the surface of the road is at an angle. This banking of the roadway takes the speed of traffic into consideration, makes it easier for vehicles to navigate the curve, and makes it less likely that a vehicle will go off the roadway at a curve. When the banking of a roadway is either insufficient or excessive, danger to motorists can increase.

  • Barriers and Guard Rails - Well placed barriers, guard rails, speed bumps, medians, curbs, and other similar devices can help separate lanes of traffic, and help prevent vehicles from crossing the median or otherwise leaving the roadway. Where such devices are inadequate in design or implementation, they can leave drivers vulnerable, or can even contribute to accidents.

  • Entry and Exit Ramps - Although in some areas traffic congestion makes it impossible to avoid backups at highway entry and exit ramps, good design can lessen congestion, provide adequate room for vehicles to merge, and avoid pinch points where vehicle density makes it difficult to change lanes.

  • Road Markings - The markings on a roadway should be visible and understandable to motorists. Sometimes the use of reflective markings and reflectors can help drivers stay in their lanes at night or in poor weather conditions. The proper use of broken and solid lines to designate areas where passing is safe or forbidden, and the proper coloration of lane markings and the fog line, can help make travel safer.

  • Road Surface - Different road surfaces offer different levels of friction. Where a higher level of friction is desired, the use of concrete as a road surface instead of asphalt can make a significant difference. Rumble strips and grooves can be used to help warn drivers of upcoming hazards, or that they are starting to drift out of their traffic lane or onto a shoulder.

  • Shoulder Design - Providing an adequate shoulder can improve the safety of a road by providing a buffer space between vehicle traffic and a barrier or ditch, and by providing motorists with a location to safely pull off the road in the event of mechanical failure. Road design should avoid any sudden drop-off from the paved roadway onto the shoulder.

  • Signage - Well-placed, properly illuminated signs make it easier for drivers to anticipate upcoming intersections and hazards, and make it less likely that they will become lost or confused.

  • Traffic Control Devices - Appropriate placement of traffic signals, stop and yield signs, lights to designate intersections, school crossings, and pedestrian crossings, and other devices to control the flow of traffic, can improve safety for both drivers and pedestrians.

  • Traffic Flow Patterns - When roads are designed, traffic speed and density should be considered. At highway speeds, roads are safest when the traffic lanes for each direction are separated. In dense urban areas, one-way roads may improve traffic flow - but the excessive use of one-way roads can also confuse drivers and impede traffic. Rural highways, with one traffic lane in each direction, tend to be more dangerous than roads with multiple lanes due to unsafe passing and an associated increased risk of head-on collision.

  • Visibility - Road design should take the terrain and local weather into consideration, including whether an area is susceptible to fog or flooding, and should attempt to avoid points of diminished visibility due to hills, curves, or at points of hazard. Buildings and structures should be appropriately set back from the road, and trees and foliage should be trimmed as necessary.

Guidelines and Regulations

There are many published guidelines relating to road design and construction which, if followed, can help make a roadway safe.

All states and the federal government have adopted regulations and guidelines governing the design and construction of public roads, and the design and placement of traffic control signs and devices.

When road design is alleged to have contributed to a motor vehicle accident or injury, state and federal guidelines can provide invaluable evidence of the adequacy or inadequacy of the design of a road or intersection, the placement of signs and traffic control devices, and the design and placement of barriers and guard rails.

Sovereign Immunity

When a claim of inadequate design or construction is made against a governmental agency or unit of government, the defense can be expected to assert sovereign immunity. Although there may be exceptions to governmental immunity that apply to the road, the analysis of immunity issues can be complex and the law varies significantly by state. Where design or construction issues may be raised in litigation, a law firm which is experienced with these issues can help identify the proper defendants, and help find applicable exceptions to the defense of sovereign immunity.

Copyright © 2006 Aaron Larson, All rights reserved. No portion of this article may be reproduced without the express written permission of the copyright holder. If you use a quotation, excerpt or paraphrase of this article, except as otherwise authorized in writing by the author of the article you must cite this article as a source for your work and include a link back to the original article from any online materials that incorporate or are derived from the content of this article.

This article was last reviewed or amended on Jul 19, 2016.