October 11, 2016 Yung Koprowski, PE, PTOE Project Manager, Lee - PowerPoint PPT Presentation

October 11, 2016 Yung Koprowski, PE, PTOE Project Manager, Lee Engineering

Overview  The UIIG story  UIIG information  UIIG toolkit  Using the UIIG

The UIIG Story

NCHRP Project 03-104  Problem statement:  Develop comprehensive guide to enhance safe operation for all users of unsignalized intersections  The Guide should be practical and multimodal and aid practitioners in selecting design, operational, maintenance, enforcement, and other types of treatments to improve safety, mobility, and accessibility  NCHRP Sr. Program Officer— Ray Derr

UIIG project team  Independent consultants:  NCHRP Oversight Panel  Tony Giancola  Technical Advisory Group  Capt. Glenn Hansen  Frank Spielberg

What is an unsignalized intersection?  Any at-grade junction of two or more public roads whose traffic movements are not controlled by a traffic signal interchanges signals

Why the UIIG 21K 2010 - 2012 fatal intersection crashes 7 of 10 w/o traffic signal Many agencies lack professional Majority transportation engineers locally-maintained

Why the UIIG  Recognition of nationwide safety issue  NHTSA data shows a 7.7 percent increase in motor vehicle traffic deaths in 2015. An estimated 35,200 people died in 2015, up from the 32,675 reported fatalities in 2014.  Recognition of local road/local agency need

Target audience of UIIG PRIMARY SECONDARY  Local road-owning  State DOTs, large local agencies agencies, consultants • Majority of • Comprehensive nature unsignalized • Provides references on intersections under variety of intersection- their control related topics • Especially useful to • Valuable resource for those without individuals without transportation safety training engineers on staff

Benefits of web-based UIIG  Allows continuous revisions (e.g., MUTCD updates)  Enables user interaction  more likely to be used  Offers hyperlinks to other internet resources that provide additional information on variety of related topics  Capitalizes upon internet-based innovations such as aerial imagery & street-level photography to illustrate real-world examples  Conducive to sharing tools to assist user in addressing intersection safety

UIIG Structure—Two main sections

UIIG Information  Background technical content that is “static” but will change as necessary  First-time UIIG users should become familiar with content  Relies heavily on links to primary resources that provide further details

Types of Unsignalized Intersections

UIIG intersection typology  Traffic control Uncontrolled YIELD STOP

Uncontrolled intersection  No approach controlled by STOP or YIELD sign  Per § 11-401 of Uniform Vehicle Code:  Driver of the vehicle on the left shall yield the right- of-way to the vehicle on the right.  Driver must also yield to any vehicle or pedestrian already in intersection  Frequently found in residential areas and very rural areas

Yield-controlled intersection  Entrance into intersection from one or more approaches controlled by YIELD sign  Drivers must decrease speed and concede R/W to users in the intersection  Adequate sight distance required  Roundabouts are only intersections at which YIELD signs control all approaches

Stop-controlled intersection  Entrance into intersection from one or more approaches controlled by STOP sign  Complete stop always required  Stop condition can apply to all approaches or minor road only

Nontraditional designs  Alter customary vehicular paths to reduce the no. and/or severity of conflict points  Two main unsignalized groups:  Circular intersections:  Full roundabout  Mini-roundabout  Residential traffic circles  U-turn-type intersections (i.e., RCUT, J-turn)

Users of Unsignalized Intersections

Unsignalized intersection users Motor Vehicle Bicyclists Pedestrians Operators • Skill & experience • Bicycle travel on the rise in U.S. vary • Compose largest user group at most • Surrounding land use • Must adhere to rules intersections of road when riding affects nos. and on it demographics • Vehicle characteristics must • Kids, seniors, persons • Skill & experience be considered vary widely w/ disabilities are often of particular • Majority of UIIG • Vulnerable users concern treatments target drivers • Vulnerable users

Improvement Process

Improvement process  UIIG’s purpose:  Assist agencies in addressing problems at unsignalized intersections  Problems can relate to safety, operations, or access for motorists and non-motorists  Problem identification and treatment implementation should follow basic improvement process, regardless of agency size

Improvement process Identify problem intersection(s) Analyze location(s) to quantify & characterize problem Identify potential treatments that may address problem Select/implement cost-effective treatment(s) Monitor over time & evaluate treatment’s effectiveness

1 - Identify problem intersection(s) Identify problem intersection(s) Analyze location(s) to quantify & characterize problem Identify potential treatments that may address problem Select/implement cost-effective treatment(s) Monitor over time & evaluate treatment’s effectiveness

1 - Identify problem intersection(s)  Nature of intersection problem can vary …  Single intersection  Several intersections along a corridor  Jurisdiction-wide

1 - Identify problem intersection(s)  Agencies learn of problems in several ways: a) Notification by public * b) Observations during police patrol or crash investigations * c) Systematic monitoring by agency staff d) Crash data analysis * Need communication channels & protocols

Improvement process Identify problem intersection(s) Analyze location(s) to quantify & characterize problem Identify potential treatments that may address problem Select/implement cost-effective treatment(s) Monitor over time & evaluate treatment’s effectiveness

2 - Analyze the intersection  Once potential problem intersection has been identified, it should be analyzed via … a) Crash analysis b) Site review and observation

2a - Collision diagrams  Crash type  Direction of travel  Approximate location

2a - Crash tabulations  Develop tabulations across multiple variables  Day vs. night  Day of week/time of day  Driver condition (belt, alcohol)  Driver age  Crash type • Right-angle • Sideswipe, same direction • Left-turn • Sideswipe, opposite direction • Rear-end (major/minor) • Pedestrian • Head on • Bicyclist

2b - Site review & observations  Internet imagery is valuable, but site visit is necessary  RSA principles offer guidance on field approach

2 – Analyze the intersection Field Crash Observations Analyses  Potential Problem Types

Improvement process Identify problem intersection(s) Analyze location(s) to quantify & characterize problem Identify potential treatments that may address problem Select/implement cost-effective treatment(s) Monitor over time & evaluate treatment’s effectiveness

3 - Identify potential treatments  This step aligns with the UIIG’s main purpose:  Describe various treatment alternatives applicable to unsignalized intersections  75 treatments identified, ranging from low-cost traffic control devices to more extensive road construction  71 engineering  4 enforcement  Education efforts also discussed  More on this later …

Improvement process Identify problem intersection(s) Analyze location(s) to quantify & characterize problem Identify potential treatments that may address problem Select/implement cost-effective treatment(s) Monitor over time & evaluate treatment’s effectiveness

4 - Select & implement treatment(s)  Step 3 likely identified multiple treatment options  Benefit-cost analysis required Estimated Estimated Benefits Costs - Crash reduction - Construction & R/W - Operational improvement - Maintenance / lifecycle

4 - Select & implement treatment(s)  Because many UIIG treatments are low-cost, potential exists to apply on a wide scale  Look for opportunities to apply systemic approach  Identify combinations of risk factors that may increase likelihood of severe crash even if one hasn’t occurred  Interjects proactive approach  May be applicable when crashes are widely scattered over many intersections (e.g., in very rural areas)

4 - Systemic example  Consider STOP AHEAD pavement marking  Published research:  Particularly effective at 3- legged and all-way stop- controlled  Low-cost strategy can easily achieve 2:1 B-C ratio  By identifying road and traffic characteristics of some hot spot intersections, this low-cost strategy could be more broadly applied across jurisdiction

Improvement process Identify problem intersection(s) Analyze location(s) to quantify & characterize problem Identify potential treatments that may address problem Select/implement cost-effective treatment(s) Monitor over time & evaluate treatment’s effectiveness