April 7, 2009 Presented by: Tom Welch State Transportation Safety Engineer

April 7, 2009Presented by:

Tom WelchState Transportation Safety Engineer

Prepared with the Assistance of:

Dr. Tom Maze & Joshua Hochstein – Iowa State University

Iowa State University’s Center for Transportation Research and Education (CTRE) administers the following programs: Bridge Engineering Center • Center for Portland Cement Concrete Pavement Technology • Construction Management & Technology • Iowa Local Technical Assistance Program • Iowa Statewide Urban Design and Specifications• Iowa Traffic Safety Data Service • Midwest Transportation Consortium • Partnership for Geotechnical Advancement • Roadway Infrastructure Management Systems

IA-330/US-65/IA-117 & IA-330/F-17 Jasper County Intersections

Discussion of Design Alternatives

DEFINING THE PROBLEMWith Traditional Expressway Intersection Design

• Typical Problem: Far-Side Right-Angle Collisions

Typical Far-Side Right-Angle Collision

* Courtesy of University of Minnesota Intersection Surveillance System Test Bed at US-52 & CSAH-9, Goodhue County, MN

DEFINING THE PROBLEMWith Traditional Expressway Intersection Design

6:42 AM CDT

Fatal Crash at US-151 & X-20, Springville, IA (Feb. 4, 2009)

Locations:

IA-330 at County Road F-17 &

IA-330/US-65/IA-117

Jasper County

F-17

US

-65

IA-3

30

US-

65

IA-3

30

IA-1

17

Fatalities:

Major Injuries:Sheridan, Wyoming84Betty SpanglerColfax, Iowa74Norma SmithChariton, Iowa82Walton CainNewton, Iowa34Christopher Carver

Broken Arrow, Oklahoma66Louise YoderMarshalltown, Iowa55Catherine LeonardColo, Iowa20Jennifer KnissMarshalltown, Iowa56Becky DeimerlyMarshalltown, Iowa78John MeadMarshalltown, Iowa66Mary MullIndianola, Iowa31Tiffany CooperChariton, Iowa77Betty CainWhitten, Iowa44Leslie HobsonEldora, Iowa46Lori Ledger

IA-330/US-65/IA-117

IA-330/US-65 & US-65/IA-117Collision Diagram

2003 - 2008

Total = 43 or 7.17/year

4 Fatal

22 Injury

17 PDO

38 Right-Angle (88%)

36 Far-Side

2 Near-Side

2 Left-Turn Leaving (5%)

3 Rear-End (7%)

CRASH TYPES: IA-330/US-65 & US-65/IA-117

Far-Side Right-Angle Crashes ARE a Problem!

95% of Right-Angle are “Far-Side” at IA-330/US-65 & US-65/IA-117

CRASH SEVERITY: IA-330/US-65 & US-65/IA-117

Maze et al., 2004

[page 79]

More Fatal & Major Injury Crashes Occur at IA-330/US-65 & US-65/IA-117 Than on

Average

MINOR ROAD DRIVER AGE IN RIGHT-ANGLE CRASHES AT IA-330/US-65 & US-65/IA-117

Elderly Drivers More Involved in these Collisions

Fatalities:

Major Injuries:

Indianola, Iowa47Brian Cole

Nevada, Iowa79Opal Kassel*

Collins, Iowa16Craig Hudson

Kamrar, Iowa73Dorothy Donahue

Kamrar, Iowa78Walter Donahue

IA-330 and Co Rd F-17

* Driver was former DOT Director

IA-330 & F-17Collision Diagram

2003 - 2008

Total = 15 or 2.50/year

2 Fatal

8 Injury

5 PDO

15 Right-Angle (100%)

11 Far-Side

4 Near-Side

CRASH TYPES: IA-330 & F-17

Far-Side Right-Angle Crashes ARE a Problem!

73% of Right-Angle are “Far-Side” at IA-330 & F-17

CRASH SEVERITY: IA-330 & F-17

Maze et al., 2004

[page 79]

More Fatal & Major Injury Crashes Occur at IA-330 & F-17 Than on Average

MINOR ROAD DRIVER AGE IN RIGHT-ANGLE CRASHES AT IA-330 & F-17

Elderly Drivers More Involved in these Collisions

Highway Crashes are Complex

Driver conditions and behavior A contributing factor in 95 percent of crashes Primary factor in 67 percent of crashes

Roadway design and environment A contributing factor in 28 percent of crashes Primary factor in 4 percent of crashes

Vehicle A contributing factor in 8 percent of crashes Primary factor in 4 percent of crashes

YOUNG & ELDERLY DRIVERS Vision and Cognition

Challenges

Peripheral Vision is important to making judgements about placement, speed, and gaps in moving traffic– Young drivers are still developing peripheral

vision– Along with other vision changes, older drivers

also begin to lose peripheral vision

The Teen Brain Is Still Under Construction

• Recent Scientific studies reveal that the teen brain is still under construction until about age 25.

• The Prefrontal Cortex is the last part to develop. It also controls: – risk-taking– judgment– impulse control– speed assessment– distance assessment– ability to handle distractions

Medical Factors - Aging Drivers

Eye Lens

• The lens of the eye becomes cloudy and yellow with age, giving faulty information for driving decisions.

Depth Perception • With age, people lose depth perception and peripheral

vision making it harder to judge distance and speed

Needed Light

• A 50-year-old needs 5 times more light to read than a 20-year old.

• At 60 he’ll need 10 times more light

ALTERNATIVES:

National Academies of Science Transportation Research Board

Project 15-30 Median Intersection Design for Rural High-

Speed Divided Highways 2009

Principal Investigator:Dr. Thomas Maze PHD, P.E.

Joshua Hochstein, Ph.D. StudentIowa State University

SIGNALIZATION

1) Creates Expressway Traffic Delay

2) Not Expected by Expressway Drivers

3) Don’t Necessarily Improve Safety (Change Crash Types, Not Severity)

4) Signals at the bottom of a hill are not desirable

DRIVER EDUCATION:

Does Driver Education Reduce Crashes?... No.

“The DeKalb County project-conducted in the U.S. in the late 1970s and early 1980s to evaluate the effectiveness of a comprehensive driver education program-stands as the most large scale, well-designed and ambitious effort to assess the impact of formal instruction.

Despite the different methods and statistical procedures that have been applied to the data, however, the findings have been extremely consistent and disappointing to the driver education community- driver education was not associated with reliable or significant decreases in crash involvement.”

Effectiveness And Role Of Driver Education And Training In A Graduated Licensing System:D. R. Mayhew and H. M. Simpson; • Date: 1996-09-09

Supported by the Insurance Institute for Highway Safety

The full report at www.Drivers.com

Why Doesn’t Driver Education Reduce Crashes?

The studies conclude that typical driver training does not change behavior.

For example it: • does not motivate drivers to use what they have learned;• does not offset inherent risk behaviors;• does not address lifestyle and related psychosocial factors;• does not carry a sustained knowledge or performance expectation

that the driver will be tested or held accountable. (“Study only for the test and forget the rest.”)

Even worse, instruction• may encourage some drivers to feel over-competent enough to take

more risks, off-setting the value of learning safety tactics.

Drivers Reality Check

• Knowledge doesn’t always translate to correct actions

• There is no substitute for experience

INCREASED ENFORCEMENT:

“It is generally considered that fear of arrest and punishment causes drivers to conform better to traffic laws and regulations and thus reduces accidents. On the other hand, there is evidence to suggest that enforcement crusades have little lasting effect. For example, in several experiments vehicle speeds and driver behavior were recorded before and after an intensive enforcement effort. No significant changes were found either in speeds or in the number of law violations. Other studies have shown that many drivers ignore speed limit and speed zone signs that do not conform with their usual driving habits.”

Dr. Clarkson H. OglesbyStanford University

Jasper Co. Sherriff Department Comments

Failure To Yield Right-of-Way Crashes2004 -2008

5-year average per/year

Vehicle Type that got pulled in front of Average annual crashes reported

This depicts crashes involving a causal driver who failed to yield the right-of-way to another vehicle at an

intersection

8 ft

16ft

16 ft

17 ft

18 ft

66 ft

149 Motorcycle

738 Van or mini-van

1224 Pickup, van, small bus

4742 Passenger car

815 Sport utility vehicle

269 Large Trucks

Cost Estimate: ≈ $7-10 Million

Safety Effectiveness Estimate:

≈ 60 – 80%

Diamond Interchang

e

(Right-Left Configuration)

Cost Estimate: ≈ $3 Million ±

Safety Effectiveness Estimate: ≈ 40% Reduction

OFFSET T-INTERSECTION

Reduces Conflict Points from 42 to 26

OFFSET T-INTERSECTIONS

26 Conflict Points

10 Crossing 16 Merge/Diverge

OFFSET T-INTERSECTIONS

J-TURN ALTERNATIVES

THE J-TURN INTERSECTION

The J-Turn Intersection utilizes a directional median opening which closes the median to minor road traffic, but still allows all maneuvers (including left-turns) from the expressway.

Closing the median eliminates direct crossing and left-turn maneuvers from the minor road, thus preventing far-side right-angle collisions. Emergency vehicles can still cross median.

THE J-TURN INTERSECTION

All minor road traffic must turn right at the main intersection. Minor road drivers who wish to cross or turn left must do so indirectly via a downstream U-turn.

THE J-TURN INTERSECTION

Out-of-the-way travel distance depends on spacing of U-turns, but 1500 to 5000 feet extra travel can be expected for a J-Turn Intersection.

However, because the movements involved are less complex, the total delay time for indirect left-turn & crossing maneuvers may be equivalent to that of direct maneuvers at a traditional at-grade intersection.

THE J-TURN INTERSECTION

Interchanges also involve out-of-the-way travel

Typical Diamond = approximately 750 feet extra

Typical loop ramp = approx. 2200 feet extra

The J-Turn Intersection reduces the total number of intersection conflict points from 42 to 24, reduces the crossing conflicts from 24 to 4, and spreads out the conflict points over a larger area.

THE J-TURN INTERSECTION

J-TURN INTERSECTION SIGNAGE EXAMPLE

J-TURN ALTERNATIVE (IA-330/US-65/IA-117)

≈ 2250 feet ≈ 1100 feet

Approximate Proposed U-Turn Spacing From Main Intersection:

J-TURN ALTERNATIVE (IA-330/F-17)

Approximate Proposed U-Turn Spacing From Main Intersection:

≈ 900 feet ≈ 1600 feet

J-TURN INTERSECTION MARYLAND TESTIMONY

• City Council Members Initially Opposed to the J-Turn Design Option (Wanted Overpass/Interchange)

Couldn’t imagine how it could possibly work

Thought it would be too complex for elderly

• After J-Turn was constructed, it became obvious safety was improved

“Can’t deny that it was a measure important for safety”

U-Turn improves sight lines (provides a better visibility angle for viewing oncoming traffic in both lanes)

• J-Turn cheaper than an Overpass/Interchange

$800,000 vs $8,000,000 (Allows DOT to spend same $ on more projects across the state – Approximately 10 J-Turn Intersections can be built for the price of 1 interchange).

Video Clip

J-TURN INTERSECTION SAFETY EVALUATION

All statistically significant reductions (90% confidence).

MARYLAND (US-301 & MD-313) 4 Years Before, 6 Years After

• 92% crash reduction overall (8.25 to 0.67 crashes/year)

• 100% reduction in right-angle collisions (22 to 0)

• 100% reduction in fatal/injury crashes (23 to 0)

4 YEARS BEFORE

1/1/1997 – 10/31/2000

MARYLAND EVALUATION

33 Crashes Total

Right-Angle = 22 (67%)

FS = 18

NS = 4

In Median = 6 (18%)

Single-Vehicle = 4 (12%)

Mainline Rear-End = 1 (3%)

Fatal/Injury = 23 (70%)

85% “Preventable”

Includes 22/23 Fatal/Injury

6 YEARS AFTER

1/1/2001 – 12/31/2006

MARYLAND

EVALUATION

4 Crashes Total

Right-Angle = 0

FS = 0, NS = 0

In Median = 0

Single-Vehicle = 3

Mainline Rear-End = 1

Fatal/Injury = 0

Site #1 6 years before & after

Sites #2 & #3 3 years before & after

J-TURN INTERSECTION SAFETY EVALUATION

North Carolina (3 Site Average)

• 57% Crash reduction overall

• 97% reduction in right-angle collisions

• 100% reduction in far-side right-angle collisions

• 55% reduction in fatal/injury crashes

J-Turn Intersection at IA-330/US-65 & US-65/IA-117 could…

Prevent 93% (40/43) of the collisions which occurred there over the last 6 years (38 right-angle & 2 left-turn leaving).

These collisions include the MOST SEVERE CRASHES (all fatal and minor injury as well as 4/5 major injury and 11/12 possible/unknown injury collisions).

THE J-TURN INTERSECTION

J-Turn Intersection at IA-330 & F-17 could…

Prevent 100% of the collisions which occurred there over the last 6 years.

THE J-TURN INTERSECTION

OTHER IOWA PROPOSED J-TURNS

US-151 & X-20, Springville, IA – Linn County

US-151 & Springville Rd.

Janesville

Cedar Falls

US-218 & C-57 (W. Cedar Wapsi Road)

Black Hawk County

OTHER IOWA PROPOSED J-TURNS

QUESTIONS?

Iowa State University’s Center for Transportation Research and Education (CTRE) administers the following programs: Bridge Engineering Center • Center for Portland Cement Concrete Pavement Technology • Construction Management & Technology • Iowa Local Technical Assistance Program • Iowa Statewide Urban Design and Specifications• Iowa Traffic Safety Data Service • Midwest Transportation Consortium • Partnership for Geotechnical Advancement • Roadway Infrastructure Management Systems

IA-330/US-65/IA-117 & IA-330/F-17 Jasper County Intersections

Discussion of Design Alternatives

OTHER OPTIONS

Offset T-Intersection at

IA-330/US-65/ IA-117

(Right-Left Configuration)

(Alternative 1b)

US-

65

US

-65

IA-3

30

IA-3

30

IA-1

17

OTHER OPTIONS

(Alternative 2a)

One Quadrant Interchange with T-

Intersection at IA-330/US-65/IA-117

OTHER OPTIONS

(Alternative 2b)

One Quadrant Interchange with

Roundabout & T-Intersection at IA-330/US-65/IA-117

OTHER OPTIONS

Two Quadrant Interchange at IA-330/US-65/IA-117

with Right-In, Right-Out Access

(Alternative 2c)

OTHER OPTIONS

(Alternative 3b)

Folded Diamond Interchange at

IA-330/US-65/IA-117