Table 3.
Individual and environmental predictors of transport CO2 emissions for different journey purposes, car CO2 shared between drivers and passengers (N = 3474).
| Variable | Level | Regression coefficients (βs) and 95% CI for standardised log-transformed carbon |
|||
|---|---|---|---|---|---|
| Commuting |
Business |
Shopping/personal |
Social/leisure |
||
| R2 = 0.54 | R2 = 0.14 | R2 = 0.18 | R2 = 0.12 | ||
| Sex | Female | 0 | 0⁎⁎⁎ | 0 | 0 |
| Male | 0.02 (−0.04, 0.08) | 0.18 (0.10, 0.26) | −0.04 (−0.12, 0.04) | −0.03 (−0.11, 0.04) | |
| Age | 18–34 years | 0⁎ | 0⁎ | 0⁎ | 0 |
| 35–49 years | 0.04 (−0.04, 0.13) | 0.08 (−0.05, 0.22) | 0.11 (−0.01, 0.23) | −0.04 (−0.16, 0.08) | |
| 50–64 years | 0.02 (−0.06, 0.11) | 0.20 (0.06, 0.34) | 0.19 (0.06, 0.32) | −0.03 (−0.16, 0.09) | |
| >65 years | −0.10 (−0.23, 0.02) | 0.24 (0.07, 0.40) | 0.20 (0.03, 0.38) | −0.04 (−0.20, 0.13) | |
| Ethnicity | White | 0⁎ | 0 | 0 | 0⁎⁎⁎ |
| Non-white | 0.21 (0.05, 0.38) | 0.06 (−0.11, 0.22) | 0.01 (−0.18, 0.19) | −0.28 (−0.44, −0.12) | |
| Any child under 16 | No | 0 | 0 | 0 | 0 |
| Yes | 0.05 (−0.04, 0.13) | 0.06 (−0.07, 0.18) | 0.08 (−0.04, 0.20) | −0.02 (−0.13, 0.09) | |
| Education | Degree | 0 | 0 | 0 | 0⁎⁎⁎ |
| A-level | 0.01 (−0.08, 0.11) | −0.05 (−0.16, 0.07) | 0.00 (−0.12, 0.11) | 0.06 (−0.05, 0.18) | |
| GCSE | 0.02 (−0.06, 0.10) | 0.01 (−0.11, 0.13) | −0.04 (−0.14, 0.06) | −0.15 (−0.26, −0.04) | |
| No formal | 0.05 (−0.03, 0.13) | −0.10 (−0.20, 0.01) | −0.14 (−0.25, −0.03) | −0.17 (−0.28, −0.06) | |
| Annual household income | >£40,000 | 0 | 0⁎⁎ | 0 | 0 |
| £20–40,000 | −0.02 (−0.11, 0.06) | −0.14 (−0.24, −0.04) | 0.10 (0.00, 0.20) | 0.02 (−0.08, 0.13) | |
| <£20,000 | −0.07 (−0.16, 0.03) | −0.17 (−0.26, −0.07) | 0.03 (−0.09, 0.14) | −0.06 (−0.17, 0.05) | |
| Housing tenure | Owned | 0 | 0 | 0 | 0 |
| Privately rented | 0.00 (−0.11, 0.11) | −0.04 (−0.17, 0.10) | −0.07 (−0.20, 0.06) | −0.03 (−0.16, 0.10) | |
| Council rented | 0.10 (−0.02, 0.21) | −0.08 (−0.20, 0.04) | −0.03 (−0.18, 0.13) | −0.09 (−0.23, 0.06) | |
| Other | 0.16 (0.03, 0.30) | −0.05 (−0.28, 0.17) | −0.11 (−0.38, 0.16) | 0.19 (−0.06, 0.43) | |
| Employment status | Full-time | 0⁎⁎⁎ | 0⁎⁎⁎ | 0⁎⁎⁎ | 0⁎⁎⁎ |
| Part−time | −0.11 (−0.21, −0.02) | −0.21 (−0.34, −0.09) | 0.04 (−0.07, 0.15) | 0.09 (−0.02, 0.20) | |
| Student | −0.33 (−0.49, −0.17) | −0.47 (−0.61, −0.33) | −0.43 (−0.61, −0.24) | −0.25 (−0.43, −0.07) | |
| Retired | −0.66 (−0.78, −0.54) | −0.73 (−0.85, −0.60) | 0.36 (0.21, 0.50) | 0.29 (0.13, 0.45) | |
| Home duties | −0.51 (−0.70, −0.32) | −0.55 (−0.69, −0.42) | 0.26 (0.07, 0.44) | 0.12 (−0.08, 0.32) | |
| Other | −0.57 (−0.72, −0.41) | −0.39 (−0.56, −0.21) | 0.08 (−0.12, 0.28) | 0.02 (−0.17, 0.22) | |
| Site | Southampton | 0 | 0 | 0 | 0 |
| Cardiff | 0.07 (−0.03, 0.16) | 0.04 (−0.07, 0.14) | 0.04 (−0.08, 0.16) | 0.03 (−0.09, 0.15) | |
| Kenilworth | 0.10 (0.00, 0.20) | 0.08 (−0.05, 0.20) | 0.09 (−0.04, 0.22) | 0.03 (−0.11, 0.17) | |
| Urban/rural status | Urban | 0 | 0 | 0 | 0∗ |
| Rural | 0.03 (−0.15, 0.22) | −0.04 (−0.25, 0.17) | 0.08 (−0.14, 0.30) | 0.22 (0.00, 0.43) | |
| Population density | Change per 10 people per hectare | 0.00 (−0.01, 0.01) | 0.00 (−0.01, 0.02) | −0.01 (−0.02, 0.01) | −0.01 (−0.02, 0.01) |
| Home-work distance | 0–2 km/no commute | −0.34 (−0.45, −0.24) | 0.02 (−0.10, 0.14) | 0.04 (−0.09, 0.17) | 0.02 (−0.10, 0.14) |
| 2–5 km | 0⁎⁎⁎ | 0 | 0 | 0 | |
| 5–10 km | 0.40 (0.29, 0.50) | 0.00 (−0.14, 0.14) | 0.03 (−0.12, 0.18) | −0.04 (−0.17, 0.10) | |
| 10–20 km | 0.67 (0.57, 0.77) | 0.07 (−0.11, 0.25) | 0.02 (−0.15, 0.19) | 0.08 (−0.09, 0.25) | |
| ⩾20 km or variable | 0.81 (0.68, 0.94) | 0.11 (−0.06, 0.27) | 0.10 (−0.05, 0.25) | 0.01 (−0.14, 0.16) | |
| Home-retail distance | Change per kilometers | −0.01 (−0.03, 0.01) | −0.01 (−0.03, 0.02) | 0.02 (−0.01, 0.04) | −0.01 (−0.04, 0.02) |
| Cars per adult in household | No cars | −0.33 (−0.42, −0.24) | 0.00 (−0.10, 0.10) | −0.60 (−0.72, −0.48) | −0.47 (−0.59, −0.36) |
| <1 Car per adult | 0⁎⁎⁎ | 0⁎⁎⁎ | 0⁎⁎⁎ | 0⁎⁎⁎ | |
| ⩾1 Cars per adult | 0.20 (0.14, 0.26) | 0.21 (0.12, 0.30) | 0.11 (0.03, 0.20) | 0.25 (0.17, 0.34) | |
| Any adult bike | No | 0 | 0⁎ | 0⁎⁎ | 0 |
| Yes | −0.03 (−0.10, 0.03) | −0.09 (−0.19, 0.00) | −0.12 (−0.21, −0.03) | −0.02 (−0.10, 0.07) | |
a Multivariable analyses adjust for all variables in column. The dependent variable is kilograms of CO2 per week transformed as log([CO2/mean(CO2)] + 0.01), meaning the unit of analysis is standard deviations of log-transformed CO2 and dimensionless.
⁎
p < 0.05.
⁎⁎
p < 0.01.
⁎⁎⁎
p < 0.001.