Research Article
Investigating the Affecting Factors of Speed Dispersion for Suburban Arterial Highways in Nanjing, China
Table 3
Description of the candidate variables considered in this study.
| | Category | Variables | | | | Max | Min | Mean | Max | Min | Mean |
| | Road condition | Median (0 = if there is a median; 1 = otherwise) | 1 | 0 | 0.4 | 1 | 0 | 0.5 | | Roadside environment (1 = agriculture; 2 = industrial, residential, office; 3 = commercial) | Percentage | 1 | 0.2 | Percentage | 1 | 0.2 | | 2 | 0.5 | 2 | 0.5 | | 3 | 0.3 | 3 | 0.3 | | Traffic condition | Heavy vehicle mix rate (%) | 0.2 | 0.1 | 0.1 | 0.2 | 0.1 | 0.1 | | Traffic volume (veh/h) | 1336 | 432 | 614.9 | 1033 | 146 | 510 | | Average speed (km/h) | 58.3 | 33.4 | 46.2 | 63.6 | 21.9 | 47.3 | | Headway (s) | 30.1 | 4.1 | 10.2 | 35.3 | 3.5 | 9.6 | | Average lane changing rate (/veh) | 1.4 | 0.2 | 0.7 | 0.4 | 0.0 | 0.1 | | Driving interference | Right turn rate at access (/h) | 982 | 0 | 166 | 530 | 0 | 16 | | Left turn rate at access (/h) | 582 | 0 | 222 | 442 | 0 | 21 | | Cross and turn around rate (/h) | 848 | 0 | 262 | 536 | 0 | 25 | | Reverse driving (driving in the wrong direction) rate (/h) | 230 | 0 | 49 | 176 | 0 | 16 | | Illegal parking (parking on the road or road side illegally) rate (/h) | 835 | 0 | 260 | 151 | 0 | 24 | | Nonmotor vehicle volume driving on the motor road (veh/h) | 1272 | 44 | 530 | 1272 | 0 | 462 |
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