1. Safety Benefits of a Traffic Signal Designed for the Color Deficient
Leonard Evans
Bloomfield Hills, Michigan
Jay Wiseman
Bountiful, Utah
please make sure sound is switched on
THE 6th THE EYE, THE BRAIN AND THE AUTO WORLD RESEARCH CONGRESS
Monday, September 16, 2013
(Presentations are 20-minutes long, plus a 10-minute Q & A - Challenge period)
Devoted to adding reason and
knowledge to public policy
ScienceServingSociety.com
Dearborn, Michigan 1

2. annual numbers of crashes at signalized intersections *
total = 1,244,000
injury = 393,000
fatal = 2,635
* From Crash factors in intersection-related crashes (NHTSA, Sept. 2010)
“There are nearly 350,000 traffic signals in the United States.”
[1] NHTSA. (2009). Traffic Safety Facts DOT HS Washington, DC: National Highway
Traffic Safety Administration. Available at
Table 29
DOT HS September 2010
Crash Factors in
Intersection-Related Crashes:
An On-Scene Perspective
On my C-drive Below is for study - above data for 2008 2 2

3. color vision deficiency – decreased ability to see color ( the incorrect term color blind is unacceptable)
various forms – but most common is inability to distinguish red from green
approximate prevalence in US:
 7% for males
 0.4% for females
68.5% of pop has driver licenses
possible safety issue when over 8 million drivers who cannot distinguish red from green are driving in nation with >> one million red/green traffic signals 3 3

4. In 2012 Jay Wiseman received U. S. Patent No
In 2012 Jay Wiseman received U.S. Patent No. 8,154,423 TRAFFIC CONTROL SYSTEM (traffic signal lights designed for the color deficient and normal vision)
Laboratory tests, designed and administered by Jay under the direction of David Strayer, found color-deficient subjects had reduced reaction time of seconds to red 4

5. case 1 – novel signal D1 = v1T1 + (v12)/2A
stop line
speed v1 reaction time T1 D1
assume driver stops just in front of stop line by applying maximum braking producing constant deceleration A
D1 = v1T1 + (v12)/2A 5 5

6. v2 = -A(T1 + Δ) + [v12 + 2Av1T1 + (A(T1 + Δ))2]1/2
case 1 – novel signal
stop line
speed v2 reaction time T2
case 2 - standard signal D2
now assume reaction time is Δ = 136 ms = T2 - T1 slower to standard signal
can still arrive just in front of stop sign if travels at lower speed, v2
D2 = v2T2 + (v22)/2A
because D2 = D1 we can solve for v2 obtaining
v2 = -A(T1 + Δ) + [v12 + 2Av1T1 + (A(T1 + Δ))2]1/2 6 6

7. express as % reduction in speed, pv, given by pv =
color-deficient driver can keep risk unchanged by reducing speed from v1 to v2
express as % reduction in speed, pv, given by pv =
100 x {v1+ A(T1 + Δ) - [v12 + 2Av1T1 + (A(T1 + Δ))2]1/2 }/ v1
with novel signal driver has level of safety as if he were travelling pv slower 7 7

8. percent change in risk = N x pv = N x 1.90 %
specific example
Δ = seconds
Δ = seconds T1 = 2.5 seconds
Δ = seconds T1 = 2.5 seconds
A = 16 ft/s v1 = 50 mph
pv = %
percent change in risk = N x pv = N x 1.90 %
for any crash N = 2
for serious-injury crash N = 3
for fatal crash N = 4 8 8

9. synthesis – benefits to color-deficient drivers
Δ = seconds leads to pv = 1.90 %
all crashes injury fatal
crashes at signalized intersections 1,244, , ,635 xxx 46, ,
number color deficient = 3.7% of population = [(7+0.4)/2]%
46, ,
value of N 2 3 4
percent increase in risk = 1.90%*N 3.8% 5.7% 7.6%
crashes preventable by novel signal 1,
above for color-deficient drivers – but additional geometric cues help all – but with a lower value of Δ = seconds 9 9

10. synthesis – benefits to ALL drivers
Δ = seconds leads to pv = 1.48 %
all crashes injury fatal
crashes at signalized intersections 1,244, , , affected population 1,244, , , value of N 2 3 4
percent decrease in risk = 1.48%*N 3.0% 4.4% 5.9%
crashes preventable by novel signal 36,822 17, 10 10

11. summary and conclusions
have estimated safety benefits for color deficient population
these additional geometric cues benefit all road users (like many changes designed to help older drivers - help all)
for information about signal
contact Jay Wiseman 11