Safety Benefits of a Traffic Signal Designed for the Color Deficient Devoted to adding reason and knowledge to public policy ScienceServingSociety.com Leonard Evans Bloomfield Hills, Michigan Jay Wiseman Bountiful, Utah Dearborn, Michigan please make sure sound is switched on

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 )

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 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 approximate prevalence in US:  7% for males  0.4% for females

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

case 1 – novel signal stop line D1D1 assume driver stops just in front of stop line by applying maximum braking producing constant deceleration A D 1 = v 1 T 1 + (v 1 2 )/2A speed v 1 reaction time T 1

case 1 – novel signal stop line D2D2 speed v 2 reaction time T 2 case 2 - standard signal now assume reaction time is Δ = 136 ms = T 2 - T 1 slower to standard signal can still arrive just in front of stop sign if travels at lower speed, v 2 D 2 = v 2 T 2 + (v 2 2 )/2A because D 2 = D 1 we can solve for v 2 obtaining v 2 = -A(T 1 + Δ) + [v Av 1 T 1 + (A(T 1 + Δ)) 2 ] 1/2

color-deficient driver can keep risk unchanged by reducing speed from v 1 to v 2 with novel signal driver has level of safety as if he were travelling p v slower express as % reduction in speed, p v, given by p v = 100 x {v 1 + A(T 1 + Δ) - [v Av 1 T 1 + (A(T 1 + Δ)) 2 ] 1/2 }/ v 1

Δ = seconds T 1 = 2.5 seconds specific example percent change in risk = N x p v = N x 1.90 % for any crashN = 2 for serious-injury crash N = 3 for fatal crash N = 4 Δ = seconds T 1 = 2.5 seconds A = 16 ft/s 2 v 1 = 50 mph Δ = seconds p v = 1.90 %

all crashes injury fatal crashes at signalized intersections 1,244, ,000 2,635 xxx 46,028 14, number color deficient = 3.7% of population = [(7+0.4)/2]% synthesis – benefits to color-deficient drivers Δ = seconds leads to p v = 1.90 % value of N234 percent increase in risk = 1.90%*N3.8%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 46,028 14,541 97

all crashes injury fatal crashes at signalized intersections 1,244, ,000 2,635 affected population 1,244, ,000 2,635 value of N234 percent decrease in risk = 1.48%*N3.0%4.4%5.9% crashes preventable by novel signal 36,82217, synthesis – benefits to ALL drivers Δ = seconds leads to p v = 1.48 %

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 summary and conclusions