Safety Benefits of a Traffic Signal Designed for the Color Deficient

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

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)

3.  7% for males  0.4% for females 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: 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

4. 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 0.136 seconds to red

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

6. stop line case 1 – novel signal D2 speed v2 reaction time T2 case 2 - standard signal now assume reaction time is Δ = 136ms = 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

7. 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 travellingpv slower

8. specific example Δ = 0.136 seconds T1 = 2.5seconds Δ = 0.136 seconds T1 = 2.5seconds A = 16 ft/s2 v1 = 50 mph Δ = 0.136 seconds pv = 1.90 % 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

9. synthesis – benefits to color-deficient drivers Δ = 0.136 seconds leads topv = 1.90 % all crashes injury fatal crashes at signalized intersections 1,244,000393,0002,635xxx 46,028 14,541 97 number color deficient = 3.7% of population = [(7+0.4)/2]% 46,028 14,541 97 value of N 2 3 4 percent increase in risk = 1.90%*N 3.8% 5.7% 7.6% crashes preventable by novel signal 1,749 829 7.4 above for color-deficient drivers – but additional geometric cues help all – but with a lower value of Δ = 0.106 seconds

10. synthesis – benefits to ALL drivers Δ = 0.106 seconds leads topv = 1.48 % all crashes injury fatal crashes at signalized intersections 1,244,000393,0002,635affected population 1,244,000393,0002,635 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 17,449 156

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 footwise@hotmail.com