Spot Speed Study Engineering 1281H Autumn, 2015
Leo Steinkerchner, Seat 12
Sam Rankin, Seat 17 Casey Schomer, Seat 7 Zarius Shroff, Seat 11
! Rice
"hurs#ay 8$00 A%
&ate of E'(eriment$ 0)*0+*15 &ate of Sumission$ 0)*2-*15
1. Intr Intro odu duct ctio ion n
Any uni.ersity must a##ress the inherent issue of traffic f/o! t is necessary for e.ery uni.ersity to (ro.i#e routes for stu#ents, staff, an# guests that is not on/y oth efficient an# safe, ut a/so costeffecti.e! Accor#ing to the S(ot S(ee# Stu#y 3rite4(, "he 6hio State 4ni.ersity ha# recei.e# com(/aints from se.era/ (e#estrians a/king on stretches of 3oo#y Hayes &ri.e an# 6/entangy Ri.er Roa# concerning the s(ee# of traffic in these areas9 2! "herefore, the (ur(ose of this e'(eriment as to use a s(ot s(ee# stu#y to measure the s(ee# of traffic f/oing through these areas, then make a recommen#ation on hether or not a##itiona/ safety (recautions are necessary! Section 2 of this re(ort co.ers the metho#s use# to carry out the e'(eriment! "his inc/u#es the e:ui(ment use#, the setu( #on (rior to testing, an# actua/ (roce#ure of the e'(eriment! Section + (ro.i#es a// of the #ata gathere# #uring the e'(eriment an# statistica/ ana/yses an# re(resentations of it! Section - #iscusses the significance of this #ata in the conte't of this s(ot s(ee# stu#y! ;ina//y, Section 5 summari
2. Experimental Methodology 2.1.
Equipment "o measure the s(ee# of the cars, on/y a sto(atch an# (remarke# /ines of orange (aint s(ace# 17= ft! a(art on 6/entangy Ri.er Roa# ere use#! "he #ata ere then recor#e# on the S(ot S(ee# Stu#y > ;ie/# Sheet, shon in A((en#i' A!
2.2.
Setup
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?rior to the e'(eriment, a 17= ft! inter.a/ as marke# ith orange (aint at @ocation as shon in ;igure 1 e/o! As in#icate# y the figure, the s(ee# /imit at @ocation is +5 m(h! As a##itiona/ (recautions, a// #ata ere taken from a safe #istance aay from the roa#, a// traffic /as concerning (e#estrians ere oeye#, an# the e'(eriment as #esigne# so as to not #isru(t the #ri.ers of the cars going (ast!
Figure 1: @ocation of S(ot S(ee# Stu#y 2!
A/so, each team memer as assigne# a ro/e for the e'(eriment, as #escrie# in "a/e 1 on the fo//oing (age! 6nce ro/es ere assigne#, the grou( #eci#e# on a han# signa/ that the ;/agger cou/# use to in#icate to the timer hen a car entere# the measurement range #escrie# in Section 2!+ E'(erimenta/ ?rocesses, on ne't (ageB!
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a!le 1: &escri(tion of ro/es for the S(ot S(ee# Stu#y 2!
Mem!er %ole
&e$cription
Recorder
Make a tally mark on the feld sheet in the row that corresponds to the time determined by the timer.
2.".
Flagger
Signal the timer when the vehicle passes the frst marker.
Exp
Timer
Start the stopwatch when he/she receives the signal rom the agger and stop the stopwatch when the vehicle passes the second marker.
Saety ngineer
!eep all members o the team sae and o"t o the road.
e ri m
ental #roce$$e$ 4(on arri.ing at the /ocation, the eather an# roa# con#itions, /ocation, time, an# (oste# s(ee# /imit ere a// #ocumente# on the fie/# sheet! At /ocation , the ;/agger stoo# at the eginning of the s(ee# tra( on the South si#e of ;igure 1B, hi/e the "imer an# Recor#er stoo# at the en# of the s(ee# tra( on the orth si#e of ;igure 1B! "he Safety Engineer mo.e# eteen these to (ositions, often staying in the mi##/e eteen them! As (er the agree#u(on signa/, as a car a((roache# the s(ee# tra(, the ;/agger raise# one arm straight into the air, signa/ing the "imer to e rea#y to start the sto(atch! "hen, (recise/y hen the car front e#ge (asse# the first orange /ine, the ;/aggerDs arm as rought sift/y ack #on to their si#e! 3hen this ha((ene#, the "imer starte# the sto(atch! f there as a grou( of cars c/ose together, the signa/ a/ays referre# to the car that as /ea#ing as it (asse# the ;/agger! 3hen the car (asse# the secon# orange /ine, 17= ft! #on the roa#, the "imer sto((e# the sto(atch! "he rea#ing on the sto( atch as to/# to the Recor#er, then #ocumente# in the a((ro(riate in of the fie/# sheet! "his (rocess as re(eate# as often as (ossi/e for rough/y +0 minutes!
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". %e$ult$ and &e$cription "esting egan at 8$-5 A% on Se(temer +, 2015 ith sunny eather an# #ry roa# con#itions! A tota/ of =- cars ere measure# #uring the time inter.a/! "he s(ee# each as tra.e//ing shon e/o in "a/e 2B as #etermine# y the time it took for each to (ass through the s(ee# tra( an# the con.ersions /iste# on the S(ot S(ee# Stu#y > ;ie/# Sheet A((en#i' B! A/so shon is the fre:uency of each s(ee# grou( as a (ercentage of a// the cars measure#, as e// as the cumu/ati.e (ercent fre:uency, hich re(resents the sum of a// cars u( to an# inc/u#ing that s(ee# grou(! ecause the #ata (ro#uce# a imo#a/ #istriution that as not re(resentati.e of the situation, the si
Speed #mph$ ()*+( +(*+ +*21 21*22 22*2) 2)*0( 0(*0 Total
Fre%"en cy ( (3 ,0 ,1 ( ( 2
&ercent Fre%"ency +.,+.+)2(.,(+.22,0.++.,++.,+,11.11-
'"m"lative &ercent Fre%"ency +.,+,(.0102.3).,++.30.)),11.11,11.11-
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a!le 2: ;re:uency of cars tra.e//ing ithin .arious s(ee# grou(s!
"hese #ata ere then (/otte# on to gra(hs ith same 'a'is one shos the (ercent fre:uency of cars tra.e//ing at a (articu/ar s(ee# aB, hi/e the other shos the cumu/ati.e (ercent fre:uency of these same cars B See A((en#i' B! 6n gra(h aB, here fre:uencies re(resent a sing/e .a/ue for s(ee#, #ata as (/otte# accor#ing to the mi##/e .a/ue of each s(ee# range ecause this as the (oint that est re(resente# each range e!g! the 28+2 m(h range as (/otte# as +0 m(hB! %eanhi/e, gra(h B re(resents #ata u( to an# inc/u#ing each s(ee# grou(, an# so its .a/ues ere (/otte# accor#ing to the to( .a/ue of each s(ee# range e!g! the 28+2 m(h range as (/otte# as +2 m(hB! 4sing these gra(hs, = significant .a/ues aout the #ata ere a((ro'imate#! "his information, as e// as the a.erage s(ee# of the cars an# the ca/cu/ate# an# estimate# stan#ar# #e.iation is summari
a!le ": Stati$tical data o' the mea$ured $peed 'requencie$.
Fra(hica/ A((ro'imations
Ca/cu/ations
&ata ?oint
Ga/ue
&ata ?oint
Ga/ue
%o#e
+) m(h
A.erage S(ee#
-0!-- m(h
+-!5--!5 m(h
Estimate# Stan#ar# &e.iation
-!00 m(h
15th ?ercenti/e S(ee#
+7 m(h
Ca/cu/ate# Stan#ar# &e.iation
-!88 m(h
85th ?ercenti/e S(ee#
-5 m(h
50th ?ercenti/e S(ee#
-0 m(h
?ercent of .ehic/es in ?ace
7+
10 m(h ?ace
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;rom gra(h aB the mo#a/ s(ee# of traffic can e seen, as it as the (oint hich corres(on#e# to the highest (ercent fre:uency! A/so #etermine# from gra(h aB as the o.era// (ace of the cars, i!e! the 10 m(h range at hich the most cars ere #ri.ing! "o fin# this, 10 m(h as (er the 'a'is of the gra(hB ere marke# on a straight e#ge, hich as then mo.e# #on from the to( of the cur.e to fin# the (oint here the /eft an# right si#es of the cur.e ere 10 m(h a(art! "o signify (ace on the gra(hs, these (oints ere marke#, an# .ertica/ /ines #ran through across the entire figureIecause the to gra(hs use the same 'a'is, the (ace can e marke# the same on oth of them! 4sing gra(h B, the 15th an# 85th (ercenti/es ere #etermine# y fin#ing the s(ee# .a/ue that reache# 15 an# 85 on the cumu/ati.e fre:uency cur.e, res(ecti.e/y shon y so/i# /ines at these .a/ues! Simi/ar/y, the 50th (ercenti/e hich as a/so the me#ianB corres(on#e# to the s(ee# .a/ue that reache# 50 on the cur.e! ;ina//y, gra(h B as use# to fin# the (ercent of cars tra.e//ing ithin the (ace! "o fin# this .a/ue, e sutracte# the .a/ue here the /oer oun# of the (ace meets the cumu/ati.e cur.e )B from the .a/ue here the u((er oun# of the (ace meets the cumu/ati.e cur.e 82B!
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//ustrate# y E:uation 1 e/o, the a.erage s(ee# as foun# y #i.i#ing the sum of a// of the carsD s(ee#s y the tota/ numer of cars! "he stan#ar# #e.iation as first estimate# y #i.i#ing the #ifference eteen the 85th (ercenti/e an# the 15th (ercenti/e y 2 E:uation 2 on ne't (ageB, an# then ca/cu/ate# using the acce(te# stan#ar# #e.iation e:uation for a sam(/e of a (o(u/ation, shon in E:uation + on the ne't (age! Sam(/e ca/cu/ations for each of these e:uations can e foun# in A((en#i' C! Σ ( n∗ s ) c P85− P 15
'J
S est = S=
√
1B 2B
2
Σ ( x i− x )
2
+B
c −1
(. &i$cu$$ion Centra/ ten#ency is the ten#ency of sam(/es of a gi.en measurement to c/uster aroun# some centra/ .a/ue9 +! y oser.ing the (ercent fre:uency cur.e, it can e note# that the #ata as c/ustere# aroun# the mo#a/ .a/ue of +) mi/es (er hour! y #efinition, this meant the #ata e'hiite# centra/ ten#ency +! %eanhi/e, the #is(ersion aroun# this centra/ (oint as fair/y sma//! "his as ecause the stan#ar# #e.iation of -!88 m(h as on/y 20 of the entire range 2- m(hB! f there stan#ar# #e.iation ere higher, it ou/# suggest the #ata ere further s(rea# out from the mean, an# therefore that the #is(ersion as higher! "he /o #is(ersion as further e.i#ence# y the fact that the (ercent of .ehic/es in the (ace as 7+, i!e! the maKority of the cars ere tra.e//ing aroun# the same s(ee#! "hese #ata, focuse# aroun# +) m(h, suggeste# that the genera/ f/o of traffic e'cee#e# the (oste# s(ee# /imit of +5 m(h! Hoe.er, accor#ing to the 6hio &e(artment of ?u/ic Safety %otor Gehic/e @as,9 in +5 m(h
minor s(ee# infraction -! "herefore, ith -0 m(h eing oth 5 m(h o.er the s(ee# /imit an# the me#ian of the #ata, 50 of measure# #ri.ers ere either oeying the (oste# s(ee# /imit or on/y committing a minor s(ee# infraction! t fo//os that 50 of measure# #ri.ers ere committing a maKor s(ee# infraction! "his #ata agree# ith stu#ies #one y the ationa/ Highay "raffic Safety A#ministration, hich foun# that -0 of #ri.ers a#mitte# to sometimes s(ee#ing, hi/e + 0 of #ri.ers a#mitte# to regu/ar/y s(ee#ing 5! "he measure# #ata referre# s(ecifica//y to traffic f/o at this (articu/ar /ocation, at this (articu/ar time of #ay an# #ay of the eek, an# at this time of year! f any of these factors ere change#, the resu/ts cou/# e affecte#! ;or e'am(/e, a stu#y #one in the mi##/e of the night, hen there are many feer cars on the roa#, might fin# that cars tra.e/ much faster than measure# here! 6r, a stu#y #one at mi##ay on an autumn Satur#ay in Co/umus cou/# fin# that cars mo.e e// e/o the s(ee# /imit #ue to the sheer numer of cars on the roa#! %eanhi/e, there ere se.era/ sources of error inherent in our e'(erimenta/ #esign! ;or instance, the use of the ;/aggerto"imer han# signa/s cause# a #e/ay in timing #ue to res(onse time that systematica//y /oere# a// .a/ues for time, increasing a// .a/ues for s(ee#! A/so, #ue to the c/ose (ro'imity of the cars an# an inai/ity to time more than one car at a timeB it as im(ossi/e to recor# the s(ee# of e.ery sing/e car! "his create# ran#om .ariance in our #ata, (otentia//y skeing it in one #irection or another, or changing the #is(ersion, as some of the cars that ent (ast ithout eing measure# ere tra.e//ing at any of the .arious s(ee#s re(resente#!
). Summary and *onclu$ion$ "he e'(eriment aime# to measure the fo//o of traffic on a (articu/ar section of 6/entangy Ri.er Roa#, then recommen# hether or not the area nee#e# more safety (recautions! t foun# that #ri.ers on 6/entangy Ri.er Roa# aroun# 8$+0 A% on a sunny an# #ry eek#ay ten# to #ri.e from &2
aout +-!- m(h to --!- m(h here the s(ee# /imit is +5 m(h! %ore #ri.ers tra.e//e# at +) m(h than any other s(ee#, though the a.erage s(ee# of a// of the cars as -0!-- m(h! ;urthermore, rough/y ha/f of the measure# #ri.ers in these con#itions #ri.e significant/y faster than the (oste# s(ee# /imit! n fin#ing these resu/ts, the e'(eriment succee#e# in measuring the s(ee# of traffic f/o in this area! Fi.en the #ata, the com(/aints from (e#estrians seem Kustifie#Imany #ri.ers are, in fact, #ri.ing e// ao.e the s(ee# /imit! f the e'(eriment ere re(eate#, it cou/# e im(ro.e# in se.era/ ays to increase the o.era// accuracy of the #ata! n or#er to outeigh the effects of reaction time on the "imerDs actions, the /ength of the s(ee# tra( shou/# e increase#! 4sing a /arger #istance ou/# create /arger .a/ues for time, hich ou/# then e /ess susce(ti/e to error #ue to reaction time, ut #oing so increases the chance that cars might change s(ee# ithin this range! n or#er to measure more of the cars going (ast, the e'(eriment cou/# e #one ith to ;/agger"imer (airs, (erha(s measuring the s(ee# of cars in #ifferent /anes, or sim(/y measuring the first an# secon# cars ithin e.ery c/uster of cars going (ast, rather than Kust the first! &oing so ou/# increase the accuracy of the resu/ts y e'c/u#ing feer #ata (oints! A/so, hi/e it is im(ossi/e to remo.e human error from this e'(eriment, if the e'(eriment ere (erforme# for a /onger (erio# of time e!g! if cars ere measure# for =0 minutes or more rather than Kust +0 minutesB an# therefore if a /arger numer of #ata (oints as otaine#, the ran#om errors ou/# ecome /ess significant, increasing the e'(erimentDs accuracy! f the uni.ersity (ro.i#e# L+00 in fun#ing, it is recommen#e# that that money e s(ent on ra#ar guns an in#i.i#ua/ ra#ar gun suita/e for this e'(eriment can cost aroun# L)5, therefore + ra#ar guns cou/# e (urchase#B =! "hese ra#ar guns cou/# entire/y e/iminate the nee# for a se(arate ;/agger an# "imer, therey re#ucing the (ossii/ity for human error significant/y! "hey ou/# a/so increase the (ossii/ity of measuring more of the cars ithin a gi.en time frame as e ou/# no /onger e restricte# to measuring on/y the first car ithin a grou( of cars! %o.ing forar#, it is recommen#e# that a stu#y &2
e #one to #etermine hat safety (recautions ou/# e most effecti.e an# costefficient at (rotecting (e#estrians in this area!
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%e'erence$ 1
S(ot S(ee# Stu#y > ;ie/# Sheet! 2015, Se(temer 8! !carmen!osu!e#u!
2
S(ot S(ee# Stu#y 3rite4(! 2015, Se(temer 8! !carmen!osu!e#u!
+
&ictionary!com! 2015, Se(temer 8! !#ictionary!reference!com!
-
&igest of 6hio$ %otor Gehic/e @as! 2015, Se(temer 8! htt($**(u/icsafety!ohio!go.*/inks*hsy7=07!(#f!
5
ationa/ Sur.ey of S(ee#ing Attitu#es an# eha.ior! 2015, Se(temer 8! htt($**!nhtsa!go.*AoutMH"SA*?ressMRe/eases*H"SAM;in#sMear/yMHa/fMofMA//M& ri.ersMe/ie.eMS(ee#ingMisMaM?ro/emMonM4!S!MRoa#s!
=
Ra#arFuns!com! 2015, Se(temer 8! htt($**!ra#arguns!com*ushne//.e/ocitys(ee#s(orts ra#argun!htm/!
+##E&I- +
S(ot S(ee# Stu#y > ;ie/# Sheet &2
Figure +1: ;ie/# Sheet for the S(ot S(ee# Stu#y #ocuments the fre:uency of .ehic/es mo.ing at (articu/ar s(ee#s as e// as con#itions of the roa# eing sam(/e# 1!
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+##E&I-
S(ot S(ee# Stu#y ;re:uency &istriution Cur.es
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Figure 2: ?ercent ;re:uency an# Cumu/ati.e ?ercent ;re:uency gra(hs for the S(ot S(ee# Stu#y sho the re/ati.e fre:uency of .ehic/es mo.ing at (articu/ar s(ee#s!
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+##E&I- *
Sam(/e Ca/cu/ations
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Sample calculation 'or Equation 1:
Σ ( n∗ s ) ( 3∗35 )+ (2∗40 )+( 1∗45 ) 230 x = = = =38.33 c 3 +2 +1 6 Sample calculation 'or Equation 2:
P85− P 15 45 mph−37 mph 8 mph S est = = = = 4 mph 2
2
2
Sample calculation 'or Equation ": 20−19
¿ ¿ 20−19 ¿ ¿ 19−19 ¿ ¿ 17−19 ¿ ¿ 16−19 ¿ ¿ ¿2 ¿ ¿ S=
¿
√
√
(
Σ x i − x ´ c −1
)
2
=√ ¿
1 + 1 +0 + 4 + 9 4
=
√
15 4
= 1.94
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+##E&I- &
Symo/s
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'
n
;re:uency of a (articu/ar s(ee# range
s
%e#an s(ee# of a (articu/ar s(ee# range m(hB
c
"ota/ numer of cars measure#
P x
Nth ?ercenti/e m(hB
S
Stan#ar# &e.iation m(hB
S est
Estimate# Stan#ar# &e.iation m(hB
x i
%easure# #ata (oint m(hB %ean s(ee# .a/ue m(hB
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