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26 CHAPTER 5 REVISED RECOMMENDATIONS FOR THE MUTCD AND RELATED CHANGES INTRODUCTION (x) mph or more below that of the first curve then a curve or turn warning sign and an advisory speed plaque should be used. In this chapter, revised recommendations are presented. The revisions are prompted by two things: (1) the responses of This recommendation had good support from the practitioners practitioners to the originally proposed recommendations in the follow-up survey. Exceptions to this came from prac- and (2) the reconciliation of the changes to the MUTCD that titioners who interpreted the "may to should" as a rule that must are needed because of the differences between the millennium be followed with at least one state indicating that this is the and 2003 editions of the MUTCD. way that a state attorney general had interpreted it. Given that It is again noted that the proposed changes to the MUTCD states have the option of adopting the MUTCD in a whole- are modest in scope. This is due to several reasons: the results sale manner or with exceptions, states that have significant from the study indicated that the basic guidelines for using problems with the language can make an exception. These curve-related TCDs are not seriously "broken" and do not need problems notwithstanding, most respondents indicated that major revision; results from this project, as well as more spe- they were supportive of the change. cific results from previous work, are sometimes inconsistent; it is virtually impossible to develop guidelines that would apply Existing Statements in the MUTCD to all situations and still be explicit (e.g., if a speed reduction of X is desired, use sign Y with chevrons and centerline markings); The precise wording of the first option in 2C.06 of the and, perhaps most importantly, most practitioners have mixed millennium edition (ME) and 2003 edition are shown below feelings regarding more explicit guidelines. Concerning the with additions in the 2003 version shown in italic: latter, there was some resistance to even listing elements of what should be considered in an engineering study, let alone ME: The horizontal alignment Turn (W1-1), Curve providing guidelines regarding how the results of such a study (W1-2), Reverse Turn (W1-3), Reverse Curve (W1-4), would be interpreted to determine the appropriate TCDs for or Winding Road (W1-5) signs may be used in advance a given horizontal curve. of situations where the horizontal roadway alignment In the paragraphs that follow, the three basic recommenda- changes. A Large Arrow. . . . tions are reiterated and discussed individually. In each instance, 2003: The horizontal alignment Turn (W1-1), Curve the original recommendation is presented and then discussed. (W1-2), Reverse Turn (W1-3), Reverse Curve (W1-4), or Winding Road (W1-5) signs (see Figure 2C-1) may be used in advance of situations where the horizontal FIRST RECOMMENDATION roadway alignment changes. A One-Direction Large Arrow. . . . Initial Proposed Statement The initial proposed statement is as follows: The messages regarding use of the noted signs are basically the same in both of these versions with only clarifying comments The first option in 2C.06 of the millennium edition of the added. MUTCD should be changed to read that horizontal alignment signs may be used in advance of situations where the roadway Final Proposed Statement alignment changes, and should be used when the alignment change would result in an advisory speed equal to or lower than the posted speed limit. The proposed revised version that results from implement- ing the first part of the first recommendation, using the 2003 The Winding Road (WI-5) sign should be used where there version as the base and showing changes in bold, is as follows: is a series of turns or curves that requires driving caution and where curve or turn signs would be too numerous to be effec- The horizontal alignment Turn (W1-1), Curve (W1-2), Reverse tive. Where any of the curves has an advisory speed that is Turn (W1-3), Reverse Curve (W1-4), or Winding Road (W1-5)