Proximity of California public schools to busy roads - Children's Health

Environmental Health Perspectives, Jan, 2004 by Rochelle S. Green, Svetlana Smorodinsky, Janice J. Kim, Robert McLaughlin, Bart Ostro

Table 1. Maximum AADT within 150 m of California public schools (K-12)
in 2000 by enrollment, school type, degree of urbanization, and
population density.

                          No attributable
                          traffic within       < 25,000
                              150 m            vehicles
                              n (%)             n (%)

Total enrollment         1,518,205 (26.1)   3,582,263 (61.5)
Total schools                2,267 (30.4)       4,484 (60.1)
School type
  Elementary                 1,781 (33.5)       3,090 (58.1)
  Middle school                309 (26.4)         740 (63.2)
  High school                  161 (17.5)         631 (68.5)
  K-12                          16 (32.7)          23 (46.9)
Degree of urbanization
  Rural (< 5,000               369 (35.1)         670 (63.8)
    people)
  Small urban (5,000-          182 (25.6)         524 (73.7)
    50,000 people)
  Urban (50,000-               164 (26.8)         418 (68.2)
    200,000 people)
  Large urban                1,442 (29.0)       2,872 (57.7)
    (> 200,000 people)
Population density (a)
  Quartile 1 (< 1,211)         711 (38.1)       1,104 (59.2)
  Quartile 2 (1,211-           603 (32.3)       1,133 (60.8)
    4,849)
  Quartile 3 (4.850-           531 (28.5)       1,129 (60.5)
    8,371)
  Quartile 4 (8,372-           421 (22.6)       1,118 (60.0)
    96,271)

                                            [greater than
                         25,000-49,999    or equal to] 50,000
                            vehicles           vehicles
                              n (%)              n (%)

Total enrollment         571,040 (9.8)        150,323 (2.6)
Total schools                536 (7.2)            173 (2.3)
School type
  Elementary                 326 (6.1)            122 (2.3)
  Middle school               91 (7.8)             31 (2.7)
  High school                112 (12.2)            17 (1.9)
  K-12                         7 (14.3)             3 (6.1)
Degree of urbanization
  Rural (< 5,000               8 (0.8)              4 (0.4)
    people)
  Small urban (5,000-          4 (0.6)              1 (0.1)
    50,000 people)
  Urban (50,000-              24 (3.9)              7 (1.1)
    200,000 people)
  Large urban                500 (10.1)           161 (3.2)
    (> 200,000 people)
Population density (a)
  Quartile 1 (< 1,211)        32 (1.7)             18 (1.0)
  Quartile 2 (1,211-          98 (5.3)             31 (1.7)
    4,849)
  Quartile 3 (4.850-         149 (8.0)             56 (3.0)
    8,371)
  Quartile 4 (8,372-         257 (13.8)            68 (3.7)
    96,271)

(a) Population per square mile of land in surrounding census tract
in 2000.

Table 2. Odds of close proximity to high and to medium traffic by
demographic characteristics of California public schools (K-12) and
surrounding census tracts in 2000.
                                                             Standardi-
                                                             zed coeff-
Variables                        Maximum AADT (a)            icient (b)

School-level variables
  Percent nonwhite (d)   [greater than or equal to] 50,000       0.34
                                   25,000-49,999                 0.25
  Percent blacks         [greater than or equal to] 50,000       0.11
                                   25,000-49,999                 0.09
  Percent Hispanic (d)   [greater than or equal to] 50,000       0.24
                                   25,000-49,999                 0.14
  Percent Asian (d)      [greater than or equal to] 50,000      -0.01
                                   25,000-49,999                 0.12
  Percent reduced-       [greater than or equal to] 50,000       0.21
    price or free                  25,000-49,999                 0.10
    meals (d)
  Percent English        [greater than or equal to] 50,000       0.26
    learners (d)                   25,000-49,999                 0.18

Census 2000 tract-
  level variables
  Natural log of         [greater than or equal to] 50,000       0.43
    population                     25,000-49,999                 0.73
    density (e)
  Percent below          [greater than or equal to] 50,000       0.13
    poverty (d)                    25,000-49,999                 0.14
  Percent without high   [greater than or equal to] 50,000       0.13
    school diploma (d)             25,000-49,999                 0.11
  Percent born           [greater than or equal to] 50,000       0.30
    abroad (d)                     25,000-49,999                 0.26

Variables                OR (c) (95% CI)

School-level variables
  Percent nonwhite (d)   1.69 (1.46-1.97)
                         1.48 (1.36-1.61)
  Percent blacks         1.51 (1.21-1.89)
                         1.38 (1.19-1.59)
  Percent Hispanic (d)   1.45 (1.28-1.64)
                         1.25 (1.16-1.35)
  Percent Asian (d)      0.96 (0.68-1.35)
                         1.57 (1.35-1.82)
  Percent reduced-       1.39 (1.21-1.60)
    price or free        1.17 (1.09-1.27)
    meals (d)
  Percent English        1.71 (1.48-1.97)
    learners (d)         1.43 (1.31-1.56)

Census 2000 tract-
  level variables
  Natural log of         1.46 (1.29-1.66)
    population           1.90 (1.72-2.09)
    density (e)
  Percent below          1.73 (1.26-2.38)
    poverty (d)          1.84 (1.52-2.21)
  Percent without high   1.37 (1.13-1.66)
    school diploma (d)   1.32 (1.18-1.48)
  Percent born           2.52 (2.00-3.17)
    abroad (d)           2.23 (1.94-2.56)

(a) AADT is the daily number of vehicles within 150 m of school.
(b) Change in the log-odds of traffic category for a one standard
deviation increase in the independent variable. (c) Odds of location
within 150 m of high traffic (maximum AADT [greater than or equal to]
50,000) versus low or very low traffic (AADT < 25,000) and odds of
location within 150 m of medium traffic (maximum AADT =25,000-49,999)
versus low or very low traffic. (d) ORs and confidence limits for a 25%
change. (e) Population density = population (in thousands) per square
mile of land in 2000. ORs and confidence limits are given for a one
unit change in the natural log of population density.

Figure 3. Percentage of schools and percentage of
total enrollment for California public schools (K-12)
in 2000, by maximum AADT within 150 m of schools

                              Schools   Total enrollment

No attributable traffic        30.39          26.08
  within 150 m
< 25,000 vehicles              60.11          61.53
25,000-49,999 vehicles          7.18           9.81
[greater than or                2.30           2.58
  equal to] 50,000 vehicles

Notes: Table made from bar graph.