Masters Theses

Date of Award

8-1994

Degree Type

Thesis

Degree Name

Master of Science

Major

Civil Engineering

Major Professor

Jack B. Humphreys

Committee Members

Arun Chatterjee, William L. Grecco

Abstract

Unfortunately, roadways are often resurfaced without restoring the shoulder surface up to the resurfaced roadway elevation. When a vehicle's tires drop off a roadway with shoulders that are lower than the roadway, the act of reentering the roadway can lead to an accident.

This study sought to determine the extent of the pavement edge dropoff problem and to recommend changes in contract scope or performance that will eliminate or mitigate such occurrences. The study involved extensive interviews with city and county engineers, public works directors, transportation consultants, governmental legal departments, resurfacing contractors, and public risk managers nationwide. In addition, a questionnaire was sent to public risk managers and resurfacing contractors to determine the experience and opinions of those that had and had not been involved in litigation involving pavement edge dropoffs.

The findings of previous research was that dropoffs of 4 or more inches were unsafe if the roadway edge is at a 90° angle to the shoulder surface. Unsuspecting drivers whose tires slip off a resurfaced roadway and onto an unimproved shoulder are likely to lose control of the vehicle as they attempt to climb back onto the roadway. This can result in the vehicle entering the oncoming lane of traffic where it may strike another vehicle head-on or in a side-swipe type collision, or the driver may lose control of the vehicle and have a one-vehicle accident.

Using a 45° angle fillet of asphalt provides a surface that may allow vehicles to climb back onto the resurfaced roadway without loss of control. Resurfacing contractors can attach a special edging device to their paving equipment.

Contract recommendations concerning scope of work in roadway resurfacing contracts to minimize the pavement edge dropoff hazard are to:1. Perform shoulder resurfacing at the same time as the roadway resurfacing, resulting in no shoulder dropoff; or2. Where resurfacing contracts must be bid separately, require the contractor to provide a 45° angle fillet of asphalt along the edge of the roadway as a part of the scope of work; and3. Install signs warning the motoring public of the existence of a low shoulder. These signs are only effective for a short period of time, and the problem should be corrected shortly after the resurfacing is complete.

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