Characterizing driver speeding behavior when using partial-automation in real-world driving

Figures & data

Figure 1. DTW speeding-exceedance profile medoids.

Table 1. Distribution of speeding parameters by speed-exceedance profile and for the overall data.

Variable	Speed-exceedance profile				All epochs
	1	2	3	4
Number of epochs	644 (19%)	611 (18%)	1,022 (30%)	1,136 (33%)	3,413
Mean speed magnitude (mph)	11.4 (+36%)	10.9 (+30%)	7.8 (–7%)	5.9 (–30%)	8.4
Max speed magnitude (mph)	16.6 (+50%)	16.0 (+44%)	9.8 (–12%)	6.6 (–41%)	11.1
Speed Std. deviation (mph)	2.5 (+67%)	2.9 (+93%)	1.3 (–13%)	0.4 (–73%)	1.5
Duration (s)	265.0 (+240%)	60.8 (–22%)	42.2 (–46%)	13.3 (–83%)	77.9

In parenthesis are the percentage increase (+) or decrease (–) relative to the overall data (all epochs).

Table 2. Multivariable model estimates for dependent variables: duration, mean speeding magnitude, max speeding magnitude, and standard deviation of speeding.

		Models
		log(Duration)	Speed magnitude		Std. deviation of speed
Predictors			Mean	Max
Intercept		3.08	4.39	2.22	–0.89
Speed-exceedance profile	2	–1.04	–0.08a	–0.75	0.36
	3	–1.39	–0.59	–0.99	0.18
	4	–2.43	–1.16	–0.56	–0.05a
Speed limit	55-60	0.28	–0.33	–0.14a	0.09
	65-70	0.49	–0.41	–0.37	0.13
Proportion ACC use		0.38	n.s.	–0.18	n.s.
Proportion PA use		0.46	n.s.	–0.39	0.05
log(Duration)		–	n.s.	0.52	–0.15
Mean magnitude		n.s.	–	0.55	–0.03
Max magnitude		0.16	0.47	–	0.26
Standard deviation		–0.42	–0.22	2.36	–

The reference model was manual driving, speed-exceedance profile 1, and speed limit 45–50. All p-values were <0.05 unless denoted with an “_a” indicating insignificant p-value. n.s. indicates that the variable was not significant.

Figure 2. Distribution of clusters across primary driving state (Manual, PA, ACC), duration, and mean speed magnitude.

Table 3. Distribution of speeding parameters, speed limit, and automation use by cluster.

		Classification
Features:		Incidental		Moderate		Elevated		Extended
		Partially-automated	Manual	Partially-automated	Manual	Partially-automated	Manual	Partially-automated	Manual
Counts		637	499	626	396	288	323	495	149
Proportion (%)		31	37	31	29	14	24	24	11
Mean of Epochs	Magnitude - mean (mph)	5.8	6.0	7.7	7.8	10.6	11.2	11.0	12.6
	Magnitude - max (mph)	6.4	6.8	9.6	10.0	15.5	16.5	15.7	19.7
	Std. deviation of speed (mph)	0.4	0.5	1.2	1.4	2.8	3.0	2.2	3.2
	Duration (s)	16.9	8.6	51.6	27.3	66.9	55.4	274.7	232.6
Speed-exceedance profile		4	4	3	3	2	2	1	1
Primary speed limit (mph)		65 (62)	65 (60)	65 (57)	65 (62)	65 (66)	65 (54)	65 (63)	65 (56)
Manual (%)		1	99	2	96	6	98	5	91
ACC (%)		12	0	17	1	18	1	26	3
PA (%)		86	1	80	2	74	1	68	6

In parenthesis is the percentage of the cluster that had the primary speed limit value.

Data availability statement

Data are AVT proprietary and at this time of writing is not publicly available.