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From page 53... ... NCHRP Web-Only Document 291: Development of a Posted Speed Limit Setting Procedure and Tool 41 APPENDIX C SPEED LIMIT SETTING APPROACHES A well-developed approach to setting speed limits should consider the factors that affect operating speeds. Read the entire page →
From page 54... ... NCHRP Web-Only Document 291: Development of a Posted Speed Limit Setting Procedure and Tool 42  Are fair in the context of traffic law.  Are accepted as reasonable by a majority of road users. Read the entire page →
From page 55... ... NCHRP Web-Only Document 291: Development of a Posted Speed Limit Setting Procedure and Tool 43 The road risk (engineering) approach uses the risks associated with the physical design of the road and the expected traffic conditions to set the speed limit. Read the entire page →
From page 56... ... NCHRP Web-Only Document 291: Development of a Posted Speed Limit Setting Procedure and Tool 44 Table 7. Advantages and disadvantages for approaches to set speed limits. Read the entire page →
From page 57... ... NCHRP Web-Only Document 291: Development of a Posted Speed Limit Setting Procedure and Tool 45 New Zealand Speed Limits The objective from New Zealand's speed limit policy (dated 2003) was "to balance the interests of mobility and safety by ensuring speed limits are safe, appropriate, and credible for the level of roadside development and the category of road for which they are set" (13) Read the entire page →
From page 58... ... NCHRP Web-Only Document 291: Development of a Posted Speed Limit Setting Procedure and Tool 46 Links available on the FHWA website provide access to the software to run USLIMTS2 along with links to the following resources:  User Guide (15) Read the entire page →
From page 59... ... NCHRP Web-Only Document 291: Development of a Posted Speed Limit Setting Procedure and Tool 47 USLIMTS provides suggested minimum section lengths (see Table 9) Read the entire page →
From page 60... ... NCHRP Web-Only Document 291: Development of a Posted Speed Limit Setting Procedure and Tool 48 Table 8. Input variables required for USLIMITS2. Read the entire page →
From page 61... ... NCHRP Web-Only Document 291: Development of a Posted Speed Limit Setting Procedure and Tool 49 Washington, now have the ability to set a 25-mph speed limit citywide. Portland, Oregon, has the authority to set residential streets at 20 mph. Read the entire page →
From page 62... ... NCHRP Web-Only Document 291: Development of a Posted Speed Limit Setting Procedure and Tool 50 is important to consider people traveling outside of motor vehicles because they are not protected from the impact of crashes." Portland provides the following four methods that the city can use to request speed limit changes:  Alternative method. For use on non-arterial streets with speed limits above 25 mph. Read the entire page →
From page 63... ... NCHRP Web-Only Document 291: Development of a Posted Speed Limit Setting Procedure and Tool 51 12 When a speed limit within a speed zone is posted, it should be within 5 mph of the 85th-percentile speed of free-flowing traffic. 16 Other factors that may be considered when establishing or reevaluating speed limits are the following: o Road characteristics, shoulder condition, grade, alignment, and sight distance, o The pace, o Roadside development and environment, o Parking practices and pedestrian activity, and o Reported crash experience for at least a 12-month period. Read the entire page →
From page 64... ... NCHRP Web-Only Document 291: Development of a Posted Speed Limit Setting Procedure and Tool 52 or both traffic control device criteria and the criteria for setting of speed limits. After review of the survey results and discussion with the NCUTCD Council, the direction was to keep the MUTCD material regarding setting speed limits broad, allowing states/local agencies to define the procedures in more detail. Read the entire page →
From page 65... ... NCHRP Web-Only Document 291: Development of a Posted Speed Limit Setting Procedure and Tool 53 (freeways, principal arterial, minor arterial, collector, and local) and five contexts (rural, rural town, suburban, urban, and urban core) Read the entire page →
From page 66... ... NCHRP Web-Only Document 291: Development of a Posted Speed Limit Setting Procedure and Tool 54 Table 12. Characteristics of roadway contexts. Read the entire page →
From page 67... ... NCHRP Web-Only Document 291: Development of a Posted Speed Limit Setting Procedure and Tool 55 from Texas, but over half are from states other than Texas (see Table 13) Read the entire page →
From page 68... ... NCHRP Web-Only Document 291: Development of a Posted Speed Limit Setting Procedure and Tool 56 Figure 4. Operating speed by posted speed limit for urban arterials. Read the entire page →
From page 69... ... NCHRP Web-Only Document 291: Development of a Posted Speed Limit Setting Procedure and Tool 57 Figure 6. Operating speed by posted speed limit for urban locals. Read the entire page →
From page 70... ... NCHRP Web-Only Document 291: Development of a Posted Speed Limit Setting Procedure and Tool 58 Figure 8. Using box plots to illustrate average operating speed by posted speed limit for city streets. Read the entire page →
From page 71... ... NCHRP Web-Only Document 291: Development of a Posted Speed Limit Setting Procedure and Tool 59  65 mph posted speed limit and LOS A: about 69 mph average speed.  70 mph posted speed limit and LOS A: about 73 mph average speed. Read the entire page →
From page 72... ... NCHRP Web-Only Document 291: Development of a Posted Speed Limit Setting Procedure and Tool 60  Florida, Speed Zoning for Highways, Roads, and Streets (18) Read the entire page →
From page 73... ... NCHRP Web-Only Document 291: Development of a Posted Speed Limit Setting Procedure and Tool 61 Table 14. Factors typically considered by U.S. Read the entire page →
From page 74... ... NCHRP Web-Only Document 291: Development of a Posted Speed Limit Setting Procedure and Tool 62  Maine -- 3 years.  Wisconsin -- 3 to 5 years. Read the entire page →
From page 75... ... NCHRP Web-Only Document 291: Development of a Posted Speed Limit Setting Procedure and Tool 63 reflection that the procedures examined focused on developed areas that would typically only have roads with curbs.  For the arterial streets available for the investigation, the HCM procedure resulted in calculated operating speeds greater than PSL when PSL is 30, 35, or 40 mph and operating speeds less than PSL when PSL is 45, 50, and 55 mph. Read the entire page →
From page 76... ... NCHRP Web-Only Document 291: Development of a Posted Speed Limit Setting Procedure and Tool 64 Table 15. Comparison of input variables used in speed prediction or suggested posted speed limit procedures for urban/suburban (or developed) Read the entire page →
From page 77... ... NCHRP Web-Only Document 291: Development of a Posted Speed Limit Setting Procedure and Tool 65 Table 16. Comparison of input variables used in speed prediction or suggested posted speed limit procedures for urban/suburban (or developed) Read the entire page →
From page 78... ... NCHRP Web-Only Document 291: Development of a Posted Speed Limit Setting Procedure and Tool 66 Table 17. Comparison of input variables used in speed prediction or suggested posted speed limit procedures for urban/suburban (or developed) Read the entire page →
From page 79... ... NCHRP Web-Only Document 291: Development of a Posted Speed Limit Setting Procedure and Tool 67 Table 18. Comparison of input variables used in speed prediction or suggested posted speed limit procedures for urban/suburban (or developed) Read the entire page →

From page 53...

... NCHRP Web-Only Document 291: Development of a Posted Speed Limit Setting Procedure and Tool 41 APPENDIX C SPEED LIMIT SETTING APPROACHES A well-developed approach to setting speed limits should consider the factors that affect operating speeds.