Table 1.
Variables used in the analysis of frequency factors of motorcyclists traffic accidents in Tehran, 2011–2016.
| Variable | Mean | SD | Minimum | Maximum | |
|---|---|---|---|---|---|
| Demographics and exposure | |||||
| Population density (n/km2) | 16,649.65 | 8582.95 | 1935.27 | 3,441,99 | |
| Population of illiterate people (n) | 21,139 | 12,737 | 4478 | 58,107 | |
| Illiteracy rate (%) | 0.06 | 0.03 | 0.03 | 0.13 | |
| Population of workforce at work parks (n) | 41,534 | 42,283 | 3981 | 197,495 | |
| Occupation rate at work (%) | 0.15 | 0.20 | 0.03 | 0.90 | |
| Student population at residential place (n) | 16,938 | 12,694 | 4278 | 49,818 | |
| Student population ratio at residential place (%) | 0.04 | 0.01 | 0.02 | 0.09 | |
| Daily travel productiona | 350,511 | 200,440 | 95,863 | 871,280 | |
| Travel production ratio | 15,741 | 7004 | 1561 | 27,621 | |
| Number of parks (n) | 35 | 23 | 6 | 91 | |
| Number of parks in square kilometer（ mean） | 1.58 | 1.03 | 0.10 | 5.07 | |
| Level of development (%) | 60.56 | 15.16 | 0.49 | 100.00 | |
| Distance traveled (m) | 15,736 | 9501 | 2906 | 39,675 | |
| Traffic volume | 57.7 | 11.1 | 43.0 | 80.0 | |
| Roads and passages networks | |||||
| Length of highways (km) | 9.31 | 10.31 | 0 | 44.10 | |
| The ratio of the length of the highways to the total length of the passages (%) | 0.32 | 0.27 | 0 | 1.06 | |
| Arterial streets length (km) | 20.91 | 16.51 | 0 | 66.90 | |
| The ratio of the length of arterial streets to the total length of the passages (%) | 0.81 | 0.66 | 0 | 2.57 | |
| Ramp and loop length (km) | 6.3 | 7.9 | 0 | 34.6 | |
| Ramp and loop ratio to the total length of the passages | 0.20 | 0.21 | 0 | 0.73 | |
| Personal vehicle ownership per capita | 0.35 | 0.12 | 0.22 | 0.68 | |
| Lack of parking (km2) | 14.23 | 606.23 | 17.91 | 2189.31 | |
| Land use | |||||
| Total land use (m2) | 18,110,266 | 10,711,801 | 6,105,032 | 40,071,922 | |
| Land use ration to total area (%) | 0.70 | 0.15 | 0.41 | 1.22 | |
| Residential use (m2) | 8,092,634 | 4,682,181 | 2,064,359 | 20,349,977 | |
| The ratio of residential use to total land use (%) | 0.34 | 0.14 | 0.10 | 0.59 | |
| Commercial use (m2) | 521,975.8 | 495,398.1 | 139,707.5 | 2,290,825.6 | |
| Commercial use ratio to total land use (%) | 0.02 | 0.01 | 0.02 | 0.05 | |
| Educational use (m2) | 314,472.9 | 157,872.3 | 61,060.8 | 591,062.9 | |
| Educational use ratio to total land use (%) | 0.02 | 0.01 | 0.01 | 0.04 | |
| Administrative use (m2) | 506,979.4 | 503,573.5 | 47,527.5 | 1,902,773.9 | |
| Administrative use ratio to total land use (%) | 0.02 | 0.02 | 0.01 | 0.08 | |
| Industrial use (m2) | 702,163.8 | 1,489,559.4 | 31,036.4 | 6,940,509.1 | |
| Industrial use ratio to total land use (%) | 0.02 | 0.03 | 0.01 | 0.13 | |
| Transportation and warehouse use (m2) | 497,527.3 | 827,650.5 | 41,485.6 | 3,243,042.4 | |
| The ratio of transportation and warehouse use to total land use (%) | 0.08 | 0.01 | 0.03 | 0.02 | |
a
Estimation is based on mathematical modeling with socio-economic variables. Number of travel attraction in each geographical unit, for instance, is calculated using:TAi = 1.620EMPEi+2.420SHOPi+62694DBi