A Clustering Approach to Identify High-Risk Taxi Drivers Based on Self-Reported Driving Behavior

Table 2

Items used to measure driving behavior.

Constructs	Items	Questions	Mean	SD
Ordinary violations	OV1	(1) Drive so close to the car in front that it would be difficult to stop in an emergency	2.50	1.03
	OV2	(2) Enter an intersection knowing that the traffic lights have already changed against you	2.55	0.73
	OV3	(3) Disregard the speed limit on a freeway or rural highway	2.23	0.89
	OV4	(4) Disregard the speed limit on a residential road	2.29	0.85
	OV5	(5) Overtake a slow driver on the inside	2.52	0.69
Aggressive violations	AV1	(1) Sound your horn to indicate your annoyance at another road user	2.41	0.73
	AV2	(2) Stay in a lane about to close until the last minute, then dive in	2.34	0.58
	AV3	(3) Pull out of an intersection so far you force your way into the traffic	2.54	0.64
	AV4	(4) Get angry at a certain type of driver and express your anger any way you can	2.47	0.69
	AV5	(5) Become angry at another driver and chase them with the intention of showing them how angry you are	2.04	0.50
	AV6	(6) Race away from the traffic lights to beat another driver	1.75	0.70
Errors	ERR1	(1) Fail to notice that pedestrians are crossing when turning into a side street from a main road	2.42	0.63
	ERR2	(2) Attempt to overtake someone that you had not noticed was signaling a right turn	1.94	0.66
	ERR3	(3) Queuing to turn left onto a main road, you pay such close attention to the traffic on the main road that you almost hit the car in front	2.20	0.74
	ERR4	(4) Miss seeing a ’’give way” sign and just avoid colliding with traffic having the right of way	2.03	0.56
	ERR5	(5) Fail to check your rear-view mirror before pulling out, changing lanes, etc.	1.65	0.65
	ERR6	(6) When turning left, nearly hit a bicycle rider who has come up on your left	2.25	0.62
	ERR7	(7) Brake too quickly on a slippery road	1.86	0.71
	ERR8	(8) Underestimate the speed of an oncoming vehicle when overtaking	1.99	0.66
Lapses	LAP1	(1) Attempt to drive away from the traffic lights in third gear	1.77	0.77
	LAP2	(2) Get into wrong lane approaching a roundabout or junction	1.96	0.82
	LAP3	(3) Forget when you left your car in the car park	1.71	0.69
	LAP4	(4) Wake up to find yourself on a wrong but more familiar destination	1.90	0.80
	LAP5	(5) Switch on one thing when you meant to switch on something else	2.14	0.92
	LAP6	(6) Misread the signs and exit from a roundabout on the wrong road	1.80	1.06
	LAP7	(7) No clear recollection of the road along which you have just raveled	1.80	0.91
	LAP8	(8) Hit something when reversing that you have not previously seen	1.94	0.45