Post on 17-Jan-2016
Engineering our Highways for Older Drivers in Minnesota
Factors that affect Older Drivers and SafetyPhysical changes Strength Flexibility Range of motion
Factors that affect Older Drivers and SafetyVision Changes Visual acuity Contrast sensitivity Glare sensitivity
Factors that affect Older Drivers and SafetyCognitive changes Working memory Selective attention Processing speed
Solutions
Make the Turning Movement Easier Increase Intersection Recognition Increase Sign Visibility Improve Contrast Improve Signal Systems
Solution: Make the Turning Movement EasierAnything you do to simplify the
operation of an intersection, particularly the demands on left-turn traffic,
is an elderly mobility countermeasure.
Solution: Make the Turning Movement EasierRealign skewed intersections
Before
After
Solution: Make the Turning Movement EasierEliminate Left Turns Roundabouts
Conventional Intersection Roundabout
High speeds Low speeds
Little response time Situation changes slowly/More PRT
High energy crashes Low energy crashes
Unforgiving environment Forgiving environment
High severity crashes Low severity crashes
Complexity Easier to judge gaps
Wide visual scans Narrow visual scans
Solution: Make the Turning Movement EasierRoundabouts
Solution: Make the Turning Movement EasierIndirect Lefts Avoids interlocking left-turning movements along divided
highways Only always right-hand turns
Solution: Intersection Recognition
Solution: Intersection Recognition Flasher beacons on signs
Solution: Intersection Recognition Intersection lighting
Solution: Intersection Recognition Advance street name signs
Solution: Increased Sign Visibility
Solution: Increased Sign Visibility Larger Signs
Solution: Increased Sign Visibility Brighter signs
Prismatic sheeting that returns nearly twice as much reflected light
Solution: Increased Sign Visibility Use fluorescent yellow or fluorescent yellow-
green for ALL yellow signs
Solution: Increased Sign Visibility Use advance street name signs
Solution: Increased Sign Visibility Use curve and intersection delineation
Solution: Improve Contrast
Solution: Improve Contrast
Wet reflective pavement markings
Solution: Improve Contrast
Rumble stripes
Solution: Improve Contrast
Contrast markings
Solution: Signal Improvements
Solution: Signal improvements LED signals
Brighter than incandescent bulbs Background shields
Easier to see in cluttered environments Left turn signal phases
protects left turners from opposing traffic
All-red clearance intervals Extra time to insure the
intersection is clear
Solution: Signal improvements One signal face per lane
(centered over each lane)
Solution: Signal improvements Supplemental signal heads – always 2 signal indications for left turn
12” Lens Mast arms instead of span wire
What is good for older drivers is almost always good for all
categories of drivers.
Contact Information
Mn/DOT Office of Traffic, Safety and Technology
Sue Groth, State Traffic Engineersue.groth@state.mn.us
Dave Engstrom, Safety Engineer david.engstrom@state.mn.us
or traffic.dot@state.mn.us