Enhancing Intersection Safety Database in Kentucky
Developing a spatial intersection database in Kentucky to prioritize and analyze intersection crashes for improved highway safety. Utilizing innovative methodologies for data maintenance, safety analysis, and performance functions integration. Addressing issues such as inaccurately located crashes and lack of proper intersection crash prioritization. The project aims to benefit various stakeholders beyond safety, including planning, maintenance, and IT departments.
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ROADWAY INTERSECTIONS DATABASE Eric Green, PE, GISP Jason Blackburn, PE Lindsay Walker, PE, PTOE, AICP Kentucky Transportation Center 09-07-16
Agenda Development of the Database Background Database Description Safety Analysis Reason for Planning Study Planning Study Process Wrap-up Current Project Status Issues and Limitations Additional Uses
Background Approximately 35 percent of all traffic crashes in Kentucky occur at intersections There is a need to prioritize intersection crashes Kentucky s Highway Safety Improvement Program ranks these intersections Crashes are not always properly located Lat/long or Linear Reference System
The New Methodology Create a maintainable spatial intersection database Use with SafetyAnalyst and Safety Performance Functions Tied to KYTC s node usage table (changes are propagated) Dynamically linked to traffic volumes and road geometry Other users: planning, maintenance, IT (not just safety) Includes all roads (state and local) Includes an area of influence
Approach Counts Count the number of s/e points for each unique route ID Odd = 1 approach (route terminates) Even = 2 approaches (route enters & exits) Subsidiary Route-Type (NC, Y, Crossovers) = No approaches
2 2 2 2 1 2 KY 1211 = 5, 1 approach US 60 = 6, 2 approaches
Calculating Entering Traffic If TYPE_OP = 1 and Knu_S_E = S , entering traffic = LAST_COUNT*1 If TYPE_OP = 1 and Knu_S_E = E , entering traffic = LAST_COUNT*0 If TYPE_OP = 2 or TYPE_OP = D, entering traffic = LAST_COUNT*0.5
Type Code Description undivided 3-leg rural full stop undivided 3-leg rural (at least) partial stop undivided 3-leg rural signal undivided 3-leg urban full stop undivided 3-leg urban (at least) partial stop undivided 3-leg urban signal undivided 4+ leg rural full stop undivided 4+ leg rural (at least) partial stop undivided 4+ leg rural signal undivided 4+ leg urban full stop undivided 4+ leg urban (at least) partial stop undivided 4+ leg urban signal divided 3-leg rural (at least) partial stop divided 3-leg rural signal divided 3-leg urban(at least) partial stop divided 3-leg urban signal divided 4+ leg rural (at least) partial stop divided 4+ leg rural signal divided 4+ leg urban(at least) partial stop divided 4+ leg urban signal Count 1 U3rF 2 U3rP 3 U3rS 4 U3uF 5 U3uP 6 U3uS 7 U4rF 8 U4rP 9 U4rS 10 U4uF 11 U4uP 12 U4uS 13 D3rP 14 D3rS 15 D3uP 16 D3uS 17 D4rP 18 D4rS 19 D4uP 20 D4uS 78 37256 96 68 10252 583 77 4202 166 89 2484 1492 729 26 1292 335 459 66 560 832
Intersection Priority List Need to rank all intersections by a safety factor Replace the traditional and inadequate Critical Rate method Regression-to-the-mean Relationship between AADT and crashes Employ state-of-the-art methodologies of the Highway Safety Manual
U.S. Department of Transportation Federal Highway Administration Regression To The Mean Sir Francis Galton, 1887 Sweet pea seed size in successive generations Mean
Model Development 20 SPFs developed for each intersection type Each model included SPFs for all and KAB crashes SPFs and observed crashes were used to calculate a new measure of safety
Potential for Crash Reduction Observed Crashes Crashes per year EB Crashes (Corrected) PCR Predicted Crashes from SPF AADT
Sort by PCR Filter by county or District Calculate the PCR for a new intersection using SPF
Reason For Study (Jason rambles on for a couple of minutes.)
Study Components Existing Conditions Intersection Geometry Manner of Collision Traffic Volumes Improvement Development HSIP Funded Projects (<$500,000) PIF Projects Short-Term Line Items Cost Estimation Documentation Contract Ready Plans
Purpose and Need Purpose To identify potential improvements at 50 identified intersections throughout KYTC District 10. Need Sight Distance Issues Multiple Access Points Signage and Striping Goals and Objectives Improvement options that address identified safety issues Construction quantities and cost estimates Solutions that are less than $500,000 where possible
Terms Critical rate factor (CRF) Crash rate for a spot or segment divided by the critical crash rate KAB Injury scale K = Fatal A = Incapacitating Injury B = Non-incapacitating Injury Potential Crash Reduction (PCR) Estimate of crash frequency reduction
Intersections Top 5 have highest fatality and injury collision rate (KAB) Next 41 ranked in order by PCR Last 4 were identified as locations with safety issues by the District
Crash Rates 40 35 30 25 20 15 10 5 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 -5 All Crashes PCR CRF
Improvement Categories Signage & Striping: 30 Sight Distance: 9 Delineation: 14 Traffic Signals: 5 Turn Lanes: 13 Access Management: 25 Realignment: 19
Improvement Considerations Adjacent Intersections Consistent Typical Section Consistent Speed Access Management Study Multiple Options Line Items for Individual Improvements
Project Cost Distribution Projects < $500,000 Projects > $500,000 33 17 May Require PIF 6 Have Options < $500,000
Additional Study Components Crash Distribution Signal Warrant Analysis Detailed Cost Estimates Standard Drawings
Summary Table County Intersection # Cross Streets Treatments Design Right-of-Way Utilities Construction Total Cost A Realignment Shift intersection away from building to improve sight distance. $50,000 $81,600 Magoffin 36-2 KY 40 at Coal Branch Road $48,000 $25,000 $205,000 B Widening Widen Coal Branch Road. C Signs Install "No Parking" signs (R8-3a) in front of the bank on KY 40. N/A $400 A Signs Sign Coal Branch Road to be one-way. $50,000 $109,600 B Realignment Widen and realign Flint Street and Higgin Street to accommodate new traffic pattern. Magoffin 36-3 KY 40 at Coal Branch Road $75,000 $15,000 $250,000 C Signs Install "No Parking" signs (R8-3a) in front of the bank on KY 40. N/A $400 A Pavement Add full lane rumble strips to slow vehicles through curve. Breathitt 37-1 KY 15 at Thorpe Road $50,000 $55,000 $15,000 $360,000 $480,000 B Sight Distance Improve sight distance with slope removal near corner of Thorpe Road. A Pavement Add new roadway between Thorpe Road and Fish Pond Loop. Breathitt 37-2 KY 15 at Thorpe Road $50,000 $300,000 $25,000 $180,000 $555,000 B Access Management Close Thorpe Road and access points between Thorpe Road and Fish Pond Loop. A Delineation Add delineators to require utilization of the center turn lane. $50,000 $45,300 Menifee 38-1 US 460 at KY 746 $0 $10,000 $106,000 B Pavement Add left turn receiving pocket on US 460. C Pavement Paint stop bar on KY 746. N/A $700 A Access Management Close access points on east side of US 460. $13,300 $50,000 Menifee 38-2 US 460 at KY 746 $0 $10,000 $74,000 B Pavement Paint stop bar on KY 746. N/A $700 A Pavement Add SB left turn pocket. $761,000 $200,000 Wolfe 39 - 1 KY 15 at Swift Camp Creek $0 $10,000 $1,090,000 B Access Management Realign Swift Camp Creek Road. $69,000 $50,000 Wolfe 39 - 2 KY 15 at Swift Camp Creek A Access Management Close road access and provide driveway for resident only. $50,000 $0 $0 $35,000 $85,000 A Pavement Install Stop signs and stop bar on driveways. N/A $3,100 KY 15 at Scuddy Mountain Rd. B Pavement Re-stripe dedicated left turn lanes on KY 15. N/A $39,100 Perry 40 - 1 $0 $10,000 $250,000 C Pavement Improve access for Scuddy Branch Road. $147,800 $50,000 N/A A Pavement Install stop signs and stop bar on driveways. $3,100 KY 15 at Scuddy Mountain Rd. B Pavement Re-stripe dedicated left turn lanes on KY 15. N/A $39,400 Perry 40 - 2 $10,000 $15,000 $305,000 C Pavement Change access to Scuddy Mountain Road from Scuddy Branch Road. $187,500 $50,000 N/A A Sight Distance Trim trees inside of curve on KY 191. $2,700 B Realignment Realign for 90 degree intersection. Wolfe 41 KY 191 at KY 746 $10,000 $25,000 $295,000 $50,000 $207,300 C Realignment Extend driveway to access center of the curve. A Signs Move stop sign on KY 1146 closer to intersection. N/A $800 B Pavement Add stop bar on KY 1146. N/A $700 Perry 42 KY 476 at KY 1146 $0 $35,000 $335,000 C Delineation Delineate KY 476 from parking area. $248,500 $50,000 Link Link
Detailed Cost Estimates INT1 INT1 INT1 INT1 OPTION 1-D (ACCESS) OPTION 2-D (ACCESS) BID CODE UNIT PRICE OPTION 2 ITEM UNIT QUANTITY TOTAL QUANTITY TOTAL QUANTITY TOTAL QUANTITY TOTAL DGA BASE 00001 TON 0 $1,259.25 $0.00 $4,520.11 $1,527.20 $20.00 63 226 76 CEMENT STABILIZED ROADBED 00008 SQ YD 0 0 0 0 $0.00 $0.00 $0.00 $0.00 $3.00 DRAINAGE BLANKET-TYPE II-ASPH 00018 TON 0 0 0 0 $0.00 $0.00 $0.00 $0.00 $43.00 ASPHALT SEAL AGGREGATE 00100 TON 0 0 $228.00 $0.00 $457.27 $0.00 $95.00 2 5 REMOVE CONCRETE MEDIAN 23839EC SQ YD 0 0 0 0 $0.00 $0.00 $0.00 $0.00 $47.00 RELOCATE LIGHT POLE EACH 0 0 0 0 $0.00 $0.00 $0.00 $0.00 $4,000.00 23836EC SAW CUT LF $2,142.00 $1,360.00 $1,360.00 $1,360.00 $3.40 630 400 400 400 20430ED THERMO RUMBLE STRIPS TY 2 24097EC LF 0 0 0 0 $0.00 $0.00 $0.00 $0.00 $30.00 DOUBLE 4' X 4' RCBC LF 0 0 0 0 $0.00 $0.00 $0.00 $0.00 $460.00 N/A 6X5 BOX CULVERT LF 0 0 0 0 $0.00 $0.00 $0.00 $0.00 $400.00 N/A EXTEND 10X6 BOX CULVERT LF 0 0 0 0 $0.00 $0.00 $0.00 $0.00 $1,400.00 N/A 10X6 BOX CULVERT HDWL EACH 0 0 0 0 $0.00 $0.00 $0.00 $0.00 $7,500.00 N/A REDI ROCK/STRONG TIE RETAINING WALL EACH 0 0 0 0 $0.00 $0.00 $0.00 $0.00 $45.00 N/A NEW LIGHTED INTERSECTION EACH 0 0 0 0 $0.00 $0.00 $0.00 $0.00 $65,000.00 N/A PERMANENT DRAINAGE EASEMENT ACRES 0 0 0 0 RIGHT OF WAY ACRES 0 0.135 0.233 0.233 TEMPORARY EASEMENT SQ FT CONSTRUCTIO N COSTS SUBTOTAL: $4,000 $2,000 $7,000 $3,000 MOBILIZATION (ROUNDED UP TO $1000) 02568 LS 3% $1,000 $1,000 $1,000 $1,000 DEMOBILIZATION (ROUNDED UP TO $1000) 02569 LS 1.50% $1,000 $1,000 $1,000 $1,000 SUBTOTAL: $6,000 $4,000 $9,000 $5,000 CONTINGENCY $2,000 $1,000 $2,000 $1,000 (20%): $10,000 $5,000 $20,000 $6,000 TOTAL: Link Link
Detailed Cost Estimates INT1 INT1 INT1 INT1 OPTION 1-D (ACCESS) OPTION 2-D (ACCESS) BID CODE UNIT PRICE OPTION 2 ITEM UNIT QUANTITY TOTAL QUANTITY TOTAL QUANTITY TOTAL QUANTITY TOTAL DGA BASE 00001 TON 0 $1,259.25 $0.00 $4,520.11 $1,527.20 $20.00 63 226 76 CEMENT STABILIZED ROADBED 00008 SQ YD 0 0 0 0 $0.00 $0.00 $0.00 $0.00 $3.00 DRAINAGE BLANKET-TYPE II-ASPH 00018 TON 0 0 0 0 $0.00 $0.00 $0.00 $0.00 $43.00 ASPHALT SEAL AGGREGATE 00100 TON 0 0 $228.00 $0.00 $457.27 $0.00 $95.00 2 5 REMOVE CONCRETE MEDIAN 23839EC SQ YD 0 0 0 0 $0.00 $0.00 $0.00 $0.00 $47.00 RELOCATE LIGHT POLE EACH 0 0 0 0 $0.00 $0.00 $0.00 $0.00 $4,000.00 23836EC SAW CUT LF $2,142.00 $1,360.00 $1,360.00 $1,360.00 $3.40 630 400 400 400 20430ED THERMO RUMBLE STRIPS TY 2 24097EC LF 0 0 0 0 $0.00 $0.00 $0.00 $0.00 $30.00 DOUBLE 4' X 4' RCBC LF 0 0 0 0 $0.00 $0.00 $0.00 $0.00 $460.00 N/A 6X5 BOX CULVERT LF 0 0 0 0 $0.00 $0.00 $0.00 $0.00 $400.00 N/A EXTEND 10X6 BOX CULVERT LF 0 0 0 0 $0.00 $0.00 $0.00 $0.00 $1,400.00 N/A 10X6 BOX CULVERT HDWL EACH 0 0 0 0 $0.00 $0.00 $0.00 $0.00 $7,500.00 N/A REDI ROCK/STRONG TIE RETAINING WALL EACH 0 0 0 0 $0.00 $0.00 $0.00 $0.00 $45.00 N/A NEW LIGHTED INTERSECTION EACH 0 0 0 0 $0.00 $0.00 $0.00 $0.00 $65,000.00 N/A PERMANENT DRAINAGE EASEMENT ACRES 0 0 0 0 RIGHT OF WAY ACRES 0 0.135 0.233 0.233 TEMPORARY EASEMENT SQ FT CONSTRUCTIO N COSTS SUBTOTAL: $4,000 $2,000 $7,000 $3,000 MOBILIZATION (ROUNDED UP TO $1000) 02568 LS 3% $1,000 $1,000 $1,000 $1,000 DEMOBILIZATION (ROUNDED UP TO $1000) 02569 LS 1.50% $1,000 $1,000 $1,000 $1,000 SUBTOTAL: $6,000 $4,000 $9,000 $5,000 CONTINGENCY $2,000 $1,000 $2,000 $1,000 (20%): $10,000 $5,000 $20,000 $6,000 TOTAL: Link Link
Standard Drawings INT1 INT1 INT1 INT1 STD DRAWING # STD DRAWING DESCRIPTION SEPIA OPTION 1-F (ACCESS) OPTION 2-F (ACCESS) 0 OPTION 2 RPM-100-09 RPM-110-06 RPM-115-04 RPM-120-06 RPM-140-04 RPM-152-07 RPM-170-08 RPM-172-06 RPS-010-10 RPX-010-04 RPX-100-02 TPM-105-02 TPM-100-02 TPM-110-02 TPM-115-02 TPM-120-02 TPM-140-02 TPM-145-02 TTC-100-03 TTC-110-02 TTC-135-01 TTD-120-01 TTD-125-01 Curb and Gutter, Curb and Valley Gutter Approaches, Entrances and Mail Box Turnout Concrete Terminal Section Type 1 Island Curb Construction Details (Rigid & Flexible Pavement) Rumble Strips Concrete Entrance Pavement and Sidewalk Sidewalk Ramps Sidewalk Ramp Concrete Pavement Joint Details Preformed Compression Joint Seal for Concrete Pavement Accessible Parking Space Details Pavement Marker Arrangements Mulit-Lane Roadways Pavement Marker Arrangements Multi-Lane Roadways Pavement Marker Arrangements Mulit-Lane Roadways Pavement Marker Arrangements Two-Lane, Two-Way Roadways Pavement Marker Arrangement Two-Lane to Four-Lane Transitions Pavement Marker Arrangements Two-Way, Left Turn Lane Pavement Marker Arrangement Channelized Intersection Lane Closure Two-Lane Highway Lane Closure Using Traffic Signals Shoulder Closure Work Zone Speed Limit and Double Fine Signs Pavement Condition Warning Signs X X X X X X Now Sepia 029 Effective 11/21/2014 Now Sepia 030 Effective 11/21/2014 X X X X X X X X X X Now Sepia 017 effective 12/13/2013 X X X X X X X X X Link Link
Consultant Lessons Learned Need Crash Records Location of Crashes District Preferences Involvement of Agencies / Divisions
Current Project Status 9 of 50 have been advanced to some degree 1 Completed 2 Under Construction 1 In Right of Way/Utilities 5 In Design PCR for Current Projects = 70.1 Projected Total Costs = $2 million
Current Issues and Limitations Unable to Separate Collision Data Crash Locations not always accurate Local Road Data Major/Minor Approaches are currently being assumed Updates are Yearly Local Knowledge
Additional Uses Roundabout analysis Help with vehicle routing (Superload) ADA inventory (Ramp Data in progress) Pavement inventory Signal timing database Expanding Existing HIS Data
