Investigation into Interactions between Accident Consequences and Traffic Signs: A Bayesian Bivariate Tobit Quantile Regression Approach

Table 1

Summary of the parameters.

Factor	Attribute	Count (proportion)
State roads	2012	131(19.7%)
	2013	131(19.7%)
	2014	131(19.7%)
	2015	131(19.7%)
	2016	141(21.2%)
Accident consequence	Death or injured	8613(40.7%)
	Material damage	12562(59.3%)
Traffic signs	Class I	381540(65.3%)
	Class II	161079(27.5%)
	Class III	41664(7.2%)
Environmental factors		Accidents (proportion)
Visibility	Day	13513(67.5%)
	Low visibility for MD	4063(20.3%)
	Low visibility for DI	2439(12.2%)
Weather	Clear sky	12902(64.5%)
	Cloudy	4043(20.2%)
	Bad weather (rain/fog/snow/other)	3039(15.3%)
	Range	Mean	S.D.
Accident rate
Material damage (MD)	Min: 0.022; Max: 19.56	0.78	1.22
Death or injured (DI)	Min: 0.017; Max: 7.95	0.56	0.80
Traffic Signs
Number of warning signs	Min: 6; Max: 2342	262.47	32.86
Number of mandatory signs	Min: 10; Max: 4457	367.39	57.06
Number of information signs	Min: 4; Max: 4224	40.66	56.50
Number of directional signs	Min: 2; Max: 973	73.12	11.63
Number of additional panels	Min: 0; Max: 942	87.73	13.18
Amount of traffic equipment	Min: 0; Max: 2339	230.83	30.57
Number of traffic signs in Class I	Min: 27; Max: 10436	932.86	133.95
Number of traffic signs in Class II	Min: 3; Max: 4030	393.84	55.93
Number of traffic signs in Class III	Min: 0; Max: 890	101.87	12.73
Number of valid traffic signs per km	Min: 5.39; Max: 72.23	18.32	8.02
Number of invalid traffic signs per km	Min: 0.28; Max: 15.97	4.31	2.26
Traffic characteristics
Speed limit, km/hr	Min: 28; Max: 98	62.54	10.38
Road length, km	Min: 1.5; Max: 644.6	66.73	8.92
AADT	Min: 229; Max: 14637	3546.61	227.99
Driver’s characteristics
Average age for MD	Min: 20; Max: 68	42.3	6.12
Average age for DI	Min: 19; Max: 65	40.7	6.69