The problem of providing a rational procedure for allowing exceptions to current design guides for secondary roads is discussed. Many paved secondary roads in iowa are in need of considerable work, mostly as rehabilitation, resurfacing, and reconstruction. Some will need considerable investment to bring them up to current design guides, sometimes when the amount of investment cannot be economically justified. The iowa design exception process, a rational decision process for determining the bases for allowing exceptions to meeting current design guides, is described. Information is also included on how the process has worked in iowa, and a case study is discussed to examine some of the issues arising during the application and reviewprocess. The procedure has proven to be a success. What remains lacking is a court test of the procedure. As of the date of writing, notort claim has been made on the basis of exceptions granted to the current design guides. This paper appears in transportation researchrecord no. 1291, Fifth international conference on low-volume roads, may 19-23, 1991, raleigh, north carolina, volume 1.
Samenvatting