?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.title=Exploring+crash-risk+factors+using+Bayes%E2%80%99+theorem+and+an+optimization+routine&rft.creator=Maher%2C+MJ&rft.creator=Imprialou%2C+M-I&rft.creator=Quddus%2C+M&rft.description=Regression+models+used+to+analyse+crash+counts+are+associated+with+some+kinds+of+data+aggregation+(either+spatial%2C+or+temporal+or+both)+that+may+result+in+inconsistent+or+incorrect+outcomes.+This+paper+introduces+a+new+non-regression+approach+for+analysing+risk+factors+affecting+crash+counts+without+aggregating+crashes.+The+method+is+an+application+of+the+Bayes%E2%80%99+Theorem+that+enables+to+compare+the+distribution+of+the+prevailing+traffic+conditions+on+a+road+network+(i.e.+a+priori)+with+the+distribution+of+traffic+conditions+just+before+crashes+(i.e.+a+posteriori).+By+making+use+of+Bayes%E2%80%99+Theorem%2C+the+probability+densities+of+continuous+explanatory+variables+are+estimated+using+kernel+density+estimation+and+a+posterior+log+likelihood+is+maximised+by+an+optimisation+routine+(Maximum+Likelihood+Estimation).+The+method+then+estimates+the+parameters+that+define+the+crash+risk+that+is+associated+with+each+of+the+examined+crash+contributory+factors.+Both+simulated+and+real-world+data+were+employed+to+demonstrate+and+validate+the+developed+theory+in+which%2C+for+example%2C+two+explanatory+traffic+variables+speed+and+volume+were+employed.+Posterior+kernel+densities+of+speed+and+volume+at+the+location+and+time+of+crashes+have+found+to+be+different+that+prior+kernel+densities+of+the+same+variables.+The+findings+are+logical+as+higher+traffic+volumes+increase+the+risk+of+all+crashes+independently+of+collision+type%2C+severity+and+time+of+occurrence.+Higher+speeds+were+found+to+decrease+the+risk+of+multiple-vehicle+crashes+at+peak-times+and+not+to+affect+significantly+multiple-vehicle+crash+occurrences+during+off-peak+times.+However%2C+the+risk+of+single+vehicle+crashes+always+increases+while+speed+increases.&rft.subject=Bayes'+theorem%3B+Crash+characteristics%3B+Crash+risk+forecasting%3B+Crash+severity%3B+Mathematical+models%3B+Risk+assessment%3B+Speed%3B+Traffic+volume&rft.publisher=Transportation+Research+Board&rft.date=2016-01&rft.type=Proceedings+paper&rft.publisher=95th+Annual+Meeting+of+the+Transportation+Research+Board&rft.language=eng&rft.source=+++++In%3A+++(Proceedings)+95th+Annual+Meeting+of+the+Transportation+Research+Board.+++Transportation+Research+Board%3A+Washington+DC%2C+USA.+(2016)+++++&rft.format=text&rft.identifier=https%3A%2F%2Fdiscovery.ucl.ac.uk%2Fid%2Feprint%2F1474935%2F3%2FTRB%25202016%2520Imprialou%2520Maher%2520Quddus%2520v8.pdf&rft.identifier=https%3A%2F%2Fdiscovery.ucl.ac.uk%2Fid%2Feprint%2F1474935%2F&rft.rights=open