Table 3 Descriptive statistics of the key selected variables.

From: Assessing motorcyclist injury severity on curved road segments with temporal dynamics and unobserved heterogeneity

Variable	2017		2018		2019		2020		2021		2022		Total
Variable	Mean	SD	Mean	SD	Mean	SD	Mean	SD	Mean	SD	Mean	SD	Mean	SD
Weather condition
Clear weather (1 if crash happened weather was clear, 0 if no)	0.818	0.386	0.815	0.389	0.820	0.384	0.853	0.355	0.818	0.386	0.841	0.366	0.827	0.378
Cloudy weather (1 if crash happened when weather was cloudy, 0 if no)	0.152	0.359	0.147	0.354	0.144	0.351	0.126	0.332	0.146	0.353	0.135	0.341	0.142	0.349
Lighting condition
Darkness (1 if crash happened in dark, 0 if no)	0.186	0.389	0.164	0.370	0.170	0.376	0.147	0.354	0.168	0.374	0.182	0.386	0.170	0.375
Daylight (1 if crash happened in daylight, 0 if no)	0.640	0.480	0.651	0.477	0.648	0.478	0.684	0.465	0.644	0.479	0.639	0.480	0.651	0.477
Roadway characteristics
Two-lane, two-way road (1 if yes, 0 if no)	0.300	0.458	0.289	0.453	0.300	0.458	0.332	0.471	0.320	0.467	0.297	0.457	0.307	0.461
Crash characteristics
Traffic control (1 if crash happened in a marked lane with traffic control, 0 if no)	0.377	0.485	0.391	0.488	0.392	0.488	0.382	0.486	0.403	0.491	0.430	0.495	0.396	0.489
Collision with fixed object (1 if yes, 0 if no)	0.311	0.463	0.303	0.459	0.317	0.465	0.308	0.462	0.337	0.473	0.334	0.472	0.318	0.466
Overturn (1 if yes, 0 if no)	0.449	0.497	0.467	0.499	0.431	0.495	0.454	0.498	0.416	0.493	0.410	0.492	0.438	0.496
Intersection (1 if crash happened at intersection, 0 if no)	0.086	0.280	0.069	0.254	0.073	0.261	0.069	0.254	0.103	0.304	0.080	0.272	0.080	0.272
First harmful event (1 when one motor vehicle is going straight, 0 if no)	0.772	0.420	0.793	0.405	0.770	0.421	0.788	0.409	0.760	0.427	0.753	0.431	0.772	0.419
Attention diverted from driving (1 if yes, 0 if no)	0.086	0.281	0.088	0.284	0.086	0.281	0.086	0.281	0.075	0.263	0.080	0.271	0.084	0.277
Road Class
City Street (1 if crash happened in city streets, 0 if no)	0.234	0.423	0.251	0.434	0.269	0.444	0.258	0.437	0.279	0.449	0.265	0.442	0.259	0.438
Farm to market road (1 if crash happened in farm to market road, 0 if no)	0.287	0.452	0.279	0.448	0.261	0.439	0.296	0.457	0.289	0.453	0.273	0.446	0.281	0.449
Traffic characteristics
Annual average daily traffic between 401 and 4000 VPD* (1 if yes, 0 if no)	0.193	0.395	0.175	0.380	0.170	0.376	0.217	0.412	0.200	0.400	0.188	0.391	0.191	0.393
No median (1 if yes, 0 if no)	0.344	0.475	0.331	0.471	0.344	0.475	0.376	0.485	0.359	0.480	0.346	0.476	0.350	0.477
Right shoulder width of 5 to 20 ft (1 if yes, 0 if no)	0.266	0.442	0.249	0.432	0.259	0.438	0.258	0.437	0.276	0.447	0.280	0.449	0.265	0.441
Left shoulder width of 5 to 20 ft (1 if yes, 0 if no)	0.247	0.431	0.230	0.421	0.244	0.429	0.241	0.428	0.253	0.435	0.261	0.439	0.246	0.431
Two lanes (1 if yes, 0 if no)	0.294	0.456	0.283	0.451	0.295	0.456	0.330	0.470	0.318	0.466	0.298	0.457	0.303	0.460
Posted speed limit
PSL [30 to 40 mph] (1 if speed was between 30 and 40 mph, 0 if no)	0.331	0.471	0.319	0.466	0.316	0.465	0.314	0.464	0.324	0.468	0.310	0.463	0.319	0.466
PSL [40 to 60 mph] (1 if speed was between 40 and 60 mph, 0 if no)	0.465	0.499	0.472	0.499	0.478	0.500	0.485	0.500	0.488	0.500	0.481	0.500	0.478	0.500
Contributing factor
Motorcyclist failed to control speed (1 if yes, 0 if no)	0.156	0.363	0.149	0.356	0.167	0.373	0.162	0.368	0.171	0.377	0.165	0.371	0.162	0.368
Motorcyclist riding at an unsafe speed (1 if yes, 0 if no)	0.266	0.442	0.246	0.431	0.240	0.427	0.275	0.446	0.245	0.430	0.243	0.429	0.253	0.435
Motorcyclist’s characteristics
Hispanic (1 if yes, 0 if no)	0.154	0.361	0.142	0.350	0.141	0.348	0.178	0.382	0.166	0.372	0.193	0.394	0.162	0.369
White (1 if yes, 0 otherwise)	0.704	0.457	0.688	0.463	0.719	0.450	0.670	0.470	0.690	0.463	0.693	0.462	0.694	0.461
Motorcyclist aged 15 to 24 years old (1 if yes, 0 if no)	0.205	0.404	0.192	0.394	0.190	0.392	0.183	0.387	0.184	0.388	0.196	0.397	0.192	0.394
Motorcyclist aged 25 to 54 years old (1 if yes, 0 if no)	0.589	0.492	0.605	0.489	0.601	0.490	0.609	0.488	0.612	0.487	0.598	0.490	0.602	0.489

VPD vehicle per day.

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Table 3 Descriptive statistics of the key selected variables.

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