N N a a t t i i o o n n a Navigation Signing for a l l
R R o o u u n Roundabouts n d d a a b b o Study Performed for: o u u t t
C Traffic Control Devices Pooled Fund Study C o o n n f f e e r r e e n n c c e TRB National Roundabouts Conference e
2 2 0 Vail, Colorado 0 0 0 5 5
D May 24, 2005 D R R A A F F T T
Vaughan W. Inman, PhD. Bryan J. Katz, PE, PTOE SAIC SAIC N N a a t t i i o Problem o n n a a l l
R R o o u u n n d
• Growing and Widespread Adoption of d a a b b o Roundabouts o u u t t
C C o o n • No Standard for Navigation Signing at n f f e e r r e e
Roundabouts n n c c e e
2 2 0 0 0 0 5 5
D D R R A A F F T T N N a a t t i i o Approach o n n a a l l
R R o o u u n n d
• State of Practice Review of Roundabout d a a b b o Navigation Signage o u u t t
C C o o n • Selection of Four Representative n f f e e r r e e
Signing Approaches for Evaluation n n c c e e
2 2 0 • Conduct Laboratory Evaluation of 0 0 0 5 5
D Comprehension of Representative D R R A A F Signs F T T N Four Signing N a a t t i i o o n n a a l Alternatives l
R R o o u u n n d d a • Conventional a b b o o u u t t
C C o • Maryland o n n f f e e r r e e n n c • Diagrammatic c e e
2 2 0 0 0 0 5 5
D •New York D R R A A F F T T N N a a t t i i o o n Conventional n a a l l
R R o Route Number Shields o u u n n d on One Assembly, d a a b b o Destination Names on o u u t t
C C
Separate Guide Sign o o n n f f e e r r e e n n c c e e
2 2 0 0 0 0 5 5
D D R R A A F F T T N N a a t t i i o o n Maryland n a a l l
R R o o u u n n d d a a b b o o u u t t
C C o o n n f f e e r r e e n n c c e e
2 2 0 0 0 0 5 5
D D R R A A F F T T N N a a t t i i o o n Diagrammatic n a a l l
R R o o u u n n d d a a b b o o u u t t
C C o o n n f f e e r r e e n n c c e e
2 2 0 0 0 0 5 5
D D R R A A F F T T N N a a t t i i o o n New York n a a l l
R R o o u u n n d d a a b b o o u u t t
C C o o n n f f e e r r e e n n c c e e
2 2 0 0 0 0 5 5
D D R R A A F F T T N N a a t t i i o Evaluation Method o n n a a l l
R R o o u u n • Study Conducted in FHWA Sign Research n d d a a b Laboratory b o o u u t t
C • Signs Presented in Context with NCUTCD C o o n n f f e Proposed Lane Markings e r r e e n n c c e • 64 Participants, 16 in Each of 4 Sign Type e
2 2 0 0 0 Groups 0 5 5
D D R • Measure Accuracy, Latency, and Confidence R A A F F T in: T – Lane Choice – Leg Identification N N a a t t i i o Anatomy of a Trial o n n a a l l
R R o o u u n 1. Destination Displayed Until Participant n d d a a b Presses Key – Participant Reads Name b o o u u t Aloud t
C C o o n 2. Signs shown for 2 s Each n f f e e r r e e n 3. Roundabout Approach with Lane Markings n c c e e
Shown Until Participant Makes Lane 2 2 0 0 0 0
Selection 5 5
D D R 4. Roundabout Diagram Shown Until R A A F F T Participant Makes Leg Identification T Navigation Sign Route- N N a a t t i i o Destination o n n a a l l
R R o Combinations o u u n n d d a Number of Number of Items of a b b o o u u t Names Route Shields Information t
C C o o n 0 3 3 n f f e e r r e e n 1 3 4 n c c e e
2 2 3 5 2 0 0 0 0 5 5
3 3 6
D D R R A 3 2 5 A F F T 3 1 4 T 3 0 3 Turn Restriction Lane Markings N (5) N a a t t i i o o n n a a l l
R R o o u u n n d d a a b b o o u u t t
C C o o n n f f e e r r e e n n c c e e
2 2 0 0 0 0 5 5
D D R R A A F F T T N 1. Destination N a a t t i i o o n n a a l l
R R o o u u n n d d a a b b o o u u t t
C C o o n n f f e e r r e e n n c c e e
2 2 0 0 0 0 5 5
D D R R A A F F T T 2. Navigation Sign(s) N N a a t t i i o o n n a a l l
R R o o u u n n d d a a b b o o u u t t
C C o o n n f f e e r r e e n n c c e e
2 2 0 0 0 0 5 5
D D R R A A F F T T 3. Lane Choice N N a a t t i i o o n n a a l l
R R o o u u n n d d a a b b o o u u t t
C C o o n n f f e e r r e e n n c c e e
2 2 0 0 0 0 5 5
D D R R A A F F T T 3b. Confidence Rating N N a a t t i i o o n n a a l l
R R o o u u n n d d a a b b o o u u t t
C C o o n n f f e e r r e e n n c c e e
2 2 0 0 0 0 5 5
D D R R A A F F T T 4. Leg Choice N N a a t t i i o o n n a a l l
R R o o u u n n d d a a b b o o u u t t
C C o o n n f f e e r r e e n n c c e e
2 2 0 0 0 0 5 5
D D R R A A F F T T 4b. Leg Choice Confidence N N a a t t i i o o n n a a l l
R R o o u u n n d d a a b b o o u u t t
C C o o n n f f e e r r e e n n c c e e
2 2 0 0 0 0 5 5
D D R R A A F F T T N N a a t t i i o Customized Keyboard o n n a a l l
R R o o u u n n d d a a b b o o u u t t
C C o o n n f f e e r r e e n n c c e e
2 2 0 0 0 0 5 5
D D R R A A F F T T N N a a t t i i o Lane Choice Findings o n n a a l l
R R o o u u n • Participants Chose the Correct Lane n d d a a b b o Only 68.6 Percent of the Time o u u t t
C C o
• Performance Only 3.6 Percent Above o n n f f e e r
Chance r e e n n c c e – With 3 equally probable choices chance e
2 2 0 performance would be 33.3 percent 0 0 0 5 5
D – However, assuming right lane for right D R R A A F turns, left lane for left turns, and either lane F T for straight through, chance performance T would be 65 percent Lane Choice by Number N N a a
of Items on Sign t t i i o o n n a a l l
R • Accuracy with 4 items was better than with 6 R o o u u n 1.0 n d d a a b b o o t u u c t
0.8 t
C C o o n n f f e 0.6 e r r e e n n on Corre i c c e e
0.4 2 2 0 0 0 0 oport 5 5 r
P D 0.2 D R R A A F F T 0.0 T 3456 Items (Destination Names + Route Shields N Speed in Making Lane N a a t t i i o o n n a a l Selection l
R R o o u u n n d
• Younger Group Responded More d a a b b o Quickly Than the Older Group to the o u u t t
C C o Conventional and Maryland Type Signs o n n f f e e r r e e
• Responses to New York and Maryland n n c c e e
2 Sign Responses were Slower than to 2 0 0 0 0 5 5
Conventional or Diagrammatic Signs D D R R A A F F T T Lane Choice Response Times N N a a t t i (< 65 Years of Age) i o o n n a a l Conventional Diagrammatic l
R R o o
Maryland New York u u n n d d a Younger Drivers a b b o 3 o u u t t
C C o o n n f f e e r r e 2 e n n c c e e
2 2 0 0 0 0 5 5
D 1 D R R A A Response Time (s) F F T T 0 3456 Items (Destination Names + Route Shields) Lane Choice Response Times N (≥ 65 Year of Age) N a a t t i i o o
Conventional Diagrammatic n n a a l l
R
Maryland New York R o o u u n n d Older Drivers d a a b 3 b o o u u t t
C C ) s o o n n f f e e r 2 r e me ( e i n n c c e e e T
2 2 0 0 0 0 ons 5 5
p 1
D D s R R e A A R F F T T 0 3456 Items (Destination Names + Route Shields) N N a a t t i i o Confidence Ratings o n n a a l l
R R o o u u n n d
• Despite High Error Rates, Participants d a a b b o Were Confident in Their Lane Choices o u u t t
C C o o n • Confidence in Choices was Significantly n f f e e r r e e
Lower for New York and Maryland n n c c e e
2 Signs than to Conventional and 2 0 0 0 0 5 5
Diagrammatic D D R R A A F F T T N N a a t t i i o Lane Choice Confidence o n n a a l l
R Not at all sure 7 R o o u u n g n d 6 d n a a ti b b a o o
5 u u t t
C C ce R o 4 o n n f f en e e d r r i e 3 e f n n n c c e e o
2 2 2 C 0 0 0 0 5 Very sure 1 5
D D R R
k A c d A ti n r F a a o F T ional m yl T nt r w Y e a e ram M g N onv a C Di Sign Type N N a a t t i i o Leg Choice o n n a a l l
R R o o u u n n d
• Leg Choices Accuracy was High Except d a a b b o for the New York Signs o u u t t
C C o – New York Sign Only One that Contains No o n n f f e e r Leg Information r e e n n c c e e
2
• Best Performance was with 2 0 0 0 0 5 5
Diagrammatic Sign, but Not Significantly
D D R R A Better than with Conventional Sign A F F T T N N a a t t i i o Leg Choice Accuracy o n n a a l l
R 1.0 R o o u u n 0.9 n d d a a b 0.8 b o o t u u c t t
C 0.7 C o o n n f 0.6 f e e r r e e n 0.5 n on Corre c c i e e
2 0.4 2 0 0 0 0 5 5 oport
0.3 r D D P R R A 0.2 A F F T 0.1 T 0.0 Conventional Diagrammatic Maryland New York N N a a t t i i o Leg Choice Speed o n n a a l l
R R o o u u n n d
• Leg Selections Took Significantly d a a b b o Longer for Maryland and New York o u u t t
C C o Signs Compared to Conventional and o n n f f e e r r e Diagrammatic e n n c c e e
2 • Response Time Differences between 2 0 0 0 0 5 5
Sign Types were Limited to Older Driver D D R R A Group and Largest for Signs with 5 and A F F T 6 Items T N N a a t t i i o Leg Choice Speed o n n a a l l
R 2.5 R o o u u n n d d a a b 2 b o o u u t t
C C o o n n me (s) f f i 1.5 e e r r e e n n c c se T e e n
2 2 o 1 0 0 0 0 sp 5 5 e
D D R R R A 0.5 A F F T T
0 Conventional Diagrammatic Maryland New York N N a a t t i i o Leg Choice Confidence o n n a a l l
R R o o u u n n d
• With Conventional and Diagrammatic d a a b b o Signs Drivers were Very Confident of o u u t t
C C o Leg Choices o n n f f e e r r e e
• Drivers were Significantly Less n n c c e e
2 Confident of Leg Choices with Maryland 2 0 0 0 0 5 5
Signs D D R R A A F • Drivers were Least Confident with New F T T York Sign (Significantly Less confident than with Maryland Sign) Confidence in Leg N N a a t t i i o Choice o n n a a l l
Conventional Diagrammatic Maryland New York R R o o u Not at All Sure 7 u n n d d a a b b
6 o o g u u n t t
ti C C a o 5 o n n f f e e r r ce R e 4 e n n c c en e e d
i 2 2 f
3 0 0 n 0 0 o 5 5
C D 2 D R R A A F F T 1 T Very Sure 3456 Items (Destination Names + Route Shields) N Conclusions and N a a t t i i o o n n a a l Recommendations l
R R o o u u n • Conventional and Diagrammatic Signs n d d a a b b o are Recommended over the Maryland o u u t t
C or New York Styles C o o n n f f e e r
• The Turn Restriction Markings were Not r e e n n c c
Effective e e
2 2 0 0 0 – Either because they were noticed in 0 5 5
D context of this experiment, or D R R A A F – Traditional turn restriction markings are not F T appropriate for US roundabouts T – Additional turn restriction research needed