Analysis of Inconsistencies Related to Design Speed, Operating Speed and Speed Limits

The objective of this research was to examine the relationship among design speeds, operating speeds and speed limits and address safety and operational concerns regarding the presence of disparities among these speed metrics. Roadway sections were selected throughout Kentucky based on the relationship between design speed and posted speed limit (greater or lower) and on the number of lanes (2 or 4). Speed data and roadway geometry data were collected along these sites to allow for the development of the appropriate models. The general conclusion for 2-lane highways is that the operating speed is different than the design speed indicating that there is no agreement between them. For the 4-lane highways there was an agreement between operating and design speeds indicating the absence of any differences. The relationship between operating speed and posted speed limit showed that for all roadways these two speed metrics were different and the posted speed limit was lower than the 85th operating speeds. The safety analysis showed in general that there were no significant safety consequences from the inconsistencies among the various speeds metrics. A set of recommended guidelines is proposed that aim in alleviating potential inconsistencies among these speed metrics focusing on selecting the design speed based on desired operating speeds to avoid possible inconsistencies that could lead to driver errors.

[1]  Andrew P Tarko,et al.  Reconciling Speed Limits with Design Speeds , 2004 .

[2]  R R Blackburn,et al.  UPDATE OF ENFORCEMENT TECHNOLOGY AND SPEED MEASUREMENT DEVICES. FINAL REPORT , 1989 .

[3]  S-P Miaou,et al.  MEASURING THE GOODNESS-OF-FIT OF ACCIDENT PREDICTION MODELS , 1996 .

[4]  Eric T. Donnell,et al.  CONCEPTUAL APPROACH TO RELATE DESIGN SPEED, OPERATING SPEED, AND POSTED SPEED LIMITS , 2002 .

[5]  R. Krammes,et al.  Speed-Profile Model for a Design-Consistency Evaluation Procedure in the United States , 2000 .

[6]  R W Stokes,et al.  Setting Speed Limits on Kansas Two-Lane Highways: Neuronet Approach , 2000 .

[7]  Marie Walz,et al.  Data analysis of the speed-related crash issue , 1991 .

[8]  Daniel R. Jessen,et al.  Operating Speed Prediction on Crest Vertical Curves of Rural Two-Lane Highways in Nebraska , 2001 .

[9]  Michael Kyte,et al.  Effect of Environmental Factors on Driver Speed: A Case Study , 1998 .

[10]  Paul J Carlson,et al.  DESIGN SPEED, OPERATING SPEED AND POSTED SPEED LIMIT PRACTICES , 2003 .

[11]  C Zegeer,et al.  EFFECT OF LANE WIDTH, SHOULDER WIDTH, AND SHOULDER TYPE ON HIGHWAY SAFETY , 1987 .

[12]  David Shinar,et al.  The Effectiveness of Stationary versus Moving Police Vehicles on Compliance with Speed Limit , 1986 .

[13]  Christo J. Bester.  Truck Speed Profiles , 2000 .

[14]  Nicholas J Garber,et al.  IMPACT OF DIFFERENTIAL SPEED LIMITS ON THE SPEED OF TRAFFIC AND THE RATE OF ACCIDENTS , 1992 .

[15]  Paul J Carlson,et al.  DESIGN SPEED, OPERATING SPEED, AND POSTED SPEED PRACTICES , 2003 .

[16]  Kerry Victoria Perrillo.  Effectiveness of speed trailers on low-speed urban roadways , 1997 .

[17]  A K Lund,et al.  The effect of laser speed-measuring devices on speed limit law enforcement in Charleston, South Carolina. , 1993, Accident; analysis and prevention.

[18]  Kenneth R. Agent,et al.  Analysis of Traffic Crash Data in Kentucky (2000 – 2004) , 2005 .

[19]  B J Mostyn,et al.  A NATIONAL SURVEY OF DRIVERS' ATTITUDES AND KNOWLEDGE ABOUT SPEED LIMITS , 1980 .

[20]  Jian John Lu,et al.  Criteria for setting speed limits in urban and suburban areas in Florida , 2003 .

[21]  J A Cirillo,et al.  INTERSTATE SYSTEM ACCIDENT RESEARCH STUDY II, INTERIM REPORT II , 1968 .

[22]  Lily Elefteriadou,et al.  Formulation and Validation of Operating Speed-Based Design Consistency Models by Bootstrapping , 1997 .

[23]  Nikiforos Stamatiadis,et al.  Safety Consequences from Design Flexibility in Rural-to-Urban Transitions , 2006 .

[24]  Kay Fitzpatrick,et al.  Design Speed, Operating Speed, and Posted Speed Survey , 1996 .

[25]  Rune Elvik,et al.  Optimal Speed Limits: Limits of Optimality Models , 2002 .

[26]  Max Cameron,et al.  Evaluation of the speed camera program in Victoria , 1994 .

[27]  Abishai Polus,et al.  Review of international design speed practices in roadway geometric design , 1998 .

[28]  Paul J Carlson,et al.  Selection of Design Speed Values , 2002 .

[29]  Kay Fitzpatrick,et al.  Design Speed, Operating Speed and Posted Speed Relationships , 1997 .

[30]  M Whitten.  HOW ARE SPEED LIMITS SET? AN EXAMPLE FROM TXDOT , 1996 .

[31]  H C Joksch,et al.  Velocity change and fatality risk in a crash--a rule of thumb. , 1993, Accident; analysis and prevention.

[32]  Kay Fitzpatrick,et al.  COMPATIBILITY OF DESIGN SPEED, OPERATING SPEED, AND POSTED SPEED. FINAL REPORT , 1995 .

[33]  Abishai Polus,et al.  Predicting Operating Speeds on Tangent Sections of Two-Lane Rural Highways , 2000 .

[34]  Said M. Easa,et al.  PREDICTION OF OPERATING SPEED ON THREE-DIMENSIONAL HIGHWAY ALIGNMENTS , 2001 .

[35]  Douglas W Harwood,et al.  Summary of Design Speed, Operating Speed, and Design Consistency Issues , 2000 .

[36]  Ezra Hauer,et al.  PREDICTION OF THE EXPECTED SAFETY PERFORMANCE OF RURAL TWO-LANE HIGHWAYS , 2000 .

[37]  Patrick T McCoy,et al.  RELATIONSHIP BETWEEN DESIGN, OPERATING AND POSTED SPEEDS UNDER HIGH-POSTED SPEED CONDITIONS , 2000 .

[38]  G. Maycock,et al.  SPEED, SPEED LIMITS AND ACCIDENTS , 1994 .

[39]  Ezra Hauer,et al.  SPEED ENFORCEMENT AND SPEED CHOICE , 1982 .

[40]  J Stuster,et al.  SYNTHESIS OF SAFETY RESEARCH RELATED TO SPEED AND SPEED MANAGEMENT , 1998 .

[41]  S M Casey,et al.  The effects of mobile roadside speedometers on traffic speeds. , 1991, Accident; analysis and prevention.

[42]  D Solomon,et al.  Accidents on main rural highways related to speed, driver, and vehicle , 1964 .

[43]  Pedro Jose Andueza.  MATHEMATICAL MODELS OF VEHICULAR SPEED ON MOUNTAIN ROADS , 2000 .

[44]  M. J. Norušis,et al.  SPSS 13.0 Guide to Data Analysis , 2000 .

[45]  R A Krammes,et al.  HIGHWAY GEOMETRIC DESIGN CONSISTENCY EVALUATION SOFTWARE , 1995 .

[46]  Parker,et al.  Effects of raising and lowering speed limits on selected roadway sections , 1997 .

[47]  C M Saunders.  THE EFFECT THE AERIAL PATROL HAS ON VEHICLE SPEEDS , 1979 .

[48]  Yasser Hassan,et al.  Modeling Operating Speed and Speed Differential on Two-Lane Rural Roads , 2005 .

[49]  James Migletz,et al.  THE EFFECT OF RADAR DRONE OPERATION ON SPEEDS AT HIGH CRASH RISK LOCATION , 1993 .

[50]  William W. Hunter,et al.  EVALUATION OF THE HALO EFFECT IN SPEED DETECTION AND ENFORCEMENT (ABRIDGEMENT) , 1976 .

[51]  F M Streff,et al.  EFFECTS OF DRONE RADAR AND POLICE ENFORCEMENT ON TRAVEL SPEEDS: TEST ON A 65 MPH FREEWAY AND 55 MPH CONSTRUCTION ZONE , 1995 .

[52]  K C Sinha,et al.  AN ANALYSIS OF SPEED LIMIT POLICIES FOR INDIANA , 2000 .

[53]  Mashrur Chowdhury,et al.  ANALYSIS OF ADVISORY SPEED SETTING CRITERIA , 1991 .