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MEMORANDUM

SUBJECT: Identification of Schools within 200 meters of U.S. Primary and Secondary Roads

FROM: Meredith Pedde, Office of Transportation and Air Quality/Assessment and Standards 

Division

Chad Bailey, Office of Transportation and Air Quality/Assessment and Standards Division

TO: Docket EPA-HQ-OAR-2011-0135

Introduction

The purpose of this memo is to describe the approach used in EPA’s analysis of students and 

schools in close proximity to primary and secondary roads in the United States, which is presented in 

section II.B.7 of the preamble to the Notice of Proposed Rulemaking (NPRM). The data used to create 

Tables 1-4 in this memo are provided as an attachment to this memo.

Methodology

EPA obtained public school data from the U.S. Department of Education’s Institute of Education 

Sciences National Center for Education Statistics (NCES).

1

 At the time this analysis was done, the most 

recent public school data available was for the 2009 – 2010 school year. These are the data used in our 

analysis. For each U.S. school (K-12), the data include the latitude and longitude, a unique NCES 

assigned ID, total number of students, number of students by race, and the number of students eligible 

for the free and reduced school lunch programs.

EPA obtained and used the U.S. Census Bureau’s 2010 TIGER/Line® Shapefiles for primary and 

secondary roads. According to the technical documentation for the 2010 Census TIGER/Line® 

Shapefiles, “Primary roads are generally divided, limited-access highways within the Federal interstate 

highway system or under state management. These highways are distinguished by the presence of 

interchanges and are accessible by ramps, and may include some toll highways.” 2 The technical 

documentation defines secondary roads as “main arteries, usually in the U.S. Highway, State Highway, 

or County Highway system. These roads have one or more lanes of traffic in each direction, may or may 

not be divided, and usually have at-grade intersections with many other roads and driveways. They 

often have both a local name and a route number.”3

EPA imported the school data into ArcMap 10.0 as a set of geocoded points using the latitude 

and longitude provided in the schools dataset. EPA also imported the primary and secondary road 

 

1

http://nces.ed.gov/ccd/bat/

2

http://www.census.gov/geo/www/tiger/tgrshp2010/TGRSHP10SF1.pdf

3

http://www.census.gov/geo/www/tiger/tgrshp2010/TGRSHP10SF1.pdf
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shapefiles into ArcMap 10.0 and then created 200 meter buffers around those roads. The school point 

data were intersected with the 200 meter road buffers to determine which schools are within 200 

meters of U.S. primary and secondary roads.

4

 Of the 99,804 U.S. schools in the dataset, 23,978 (24%) 

were identified to be located within the 200 meter buffers of U.S. primary and secondary roads.5 Of the 

23,978 schools within 200 meters of a primary or secondary road, 1,649 are near primary roads and 

22,329 are near secondary roads, representing 1.7% and 22.4% of total schools, respectively.

This method of determining which schools are within 200 meters of primary or secondary roads

underestimates the total number of schools from the edges of roads since the road shapefiles are line 

data – not polygon data. The line data represents the center line of a road (i.e., the center line between 

both directions of traffic), whereas polygon data would represent the area the roads encompass (i.e., 

the edges of a road). In situations where there are six lanes of traffic in each direction, for example, 

approximately 40 meters of the 200 meter buffers could be the road itself, resulting in the intersection 

analysis only identifying schools that are within approximately 160 meters of the edge of the road. 

Analysis of Racial Demographics

Using SAS 9.1, EPA evaluated the racial composition and Hispanic status of the 49,136,240 

students at the 99,804 U.S. schools, by number and percent of total students. This data is presented in 

Table 1.

Table 1: Number and Percent of Students by Race and Hispanic Status at all U.S. Schools6

American 

Indian/Alaskan 

Native

Asian/Pacific 

Islander Black Hispanic White 

Two or 

More 

Races

No Race 

Reported Total

Number 

of 

Students

584,756 2,461,820 8,166,410 10,775,975 26,311,473 334,459 501,347 49,136,240

 

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This approach does not consider the physical footprints of the schools, but represents each school as a discrete 

point in space. As such, the intersection of school points with roadway buffers represents an indicator of proximity 

to roadways with a degree of measurement error. Two primary sources of measurement error can be present. 

First, it is unknown where on school property each latitude/longitude coordinate represents (e.g., front office, 

school center). Second, schools have area in space not represented by a point, which may lead to some 

underestimation of the number of schools near major roads (i.e., where one wing of a school is nearby, but the 

coordinates are not).”

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182 of these 23,978 schools were identified as ‘temporarily closed’ and 97 were identified ‘to be operational 

within two years.’ Neither of these types of schools had any student enrollment information (i.e., these 279 

schools had total students of 0), so there are no students from these types of schools included in the student racial 

or SES analysis. 

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In the dataset used here, race designations refer to non-Hispanic students. Hispanics are enumerated separately. 
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Percent 

of Total 1.19% 5.01% 16.62% 21.93% 53.55% 0.68% 1.02% 100.00%

EPA also evaluated the racial composition and Hispanic status of students at only the 23,978 

schools within the 200 meter buffers of U.S. primary and secondary roads. Table 2 shows the number of 

students, by race, at these schools, as well as the percent of students by race.

Table 2: Number and Percent of Students by Race and Hispanic Status at U.S. Schools within 200 meters 

of Primary and Secondary Roads, by Road Type

American 

Indian/Alaskan 

Native

Asian/Pacific 

Islander Black Hispanic White 

Two or 

More 

Races

No Race 

Reported Total

Primary 

Road

Number 

of 

Students

6,242 56,105 175,128 244,618 313,169 9,216 7,409 811,887

Percent 

of Total 0.77% 6.91% 21.57% 30.13% 38.57% 1.14% 0.91% 100.00%

Secondary 

Road

Number 

of 

Students

121,373 278,209 1,535,625 1,213,743 5,943,786 33,899 92,338 9,218,973

Percent 

of Total 1.32% 3.02% 16.66% 13.17% 64.47% 0.37% 1.00% 100.00%

Primary 

and 

Secondary 

Roads

Number 

of 

Students

127,615 334,314 1,710,753 1,458,361 6,256,955 43,115 99,747 10,030,860

Percent 

of Total 1.27% 3.33% 17.05% 14.54% 62.38% 0.43% 0.99% 100.00%

The data in Tables 1 and 2 shows that minorities are overrepresented at schools located within 

200 meters of primary and secondary roads, with the overrepresentation being largest among students 

at schools located within 200 meters of primary roads. The highlighted cells in Table 2 indicate that a 

race is overrepresented in the student population for either the set of schools within the 200 meter 

buffers of primary roads, secondary roads, or primary and secondary roads combined, as compared to 
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the racial distribution of students attending all of the 99,804 schools in the U.S.7For example, Black 

students represent 21.57% of students at schools located within 200 meters of a primary road, whereas 

Black students represent 16.62% of students in all U.S. schools. Hispanic students represent 30.13% of 

students at schools located within 200 meters of a primary road, whereas Hispanic students represent 

21.93% of students in all U.S. schools.

Figures 1-3 presents cumulative distributions of the demographic compositions of student 

bodies schools near primary and secondary roads compared with all U.S. schools. Figure 1 depicts the 

cumulative (percentile) distributions of the percentage of nonwhite and Hispanic students for schools 

near primary roads, secondary roads, and all schools. Consistent with the tabular data presented in 

Tables 1 and 2, across the entire distribution of schools, those near primary roads have higher nonwhite 

student fractions than other schools. 

Figure 1 – Cumulative Distribution of Student Nonwhite Percentages for Schools Near and Far from 

Major Roads

 

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The highlighted race proportions in Table 2 were tested against the corresponding race’s proportion in Table 1 to 

determine if the difference in the race’s proportion in the observed populations (i.e., the race distributions for the 

schools within 200 meters of primary, secondary, and primary and secondary roads combined) and the whole U.S. 

population of schools is statistically significant. Using a chi-square goodness of fit test, the differences in the 

highlighted percentages in Table 2 and the corresponding percentages in Table 1 were all statistically significant (p 

< 0.0001).
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Figure 2 depicts the cumulative (percentile) distributions of the percentage of Hispanic students for 

schools near primary and secondary roads, and for all schools. Consistent with the tabular data 

presented in Tables 1 and 2, across the entire distribution of schools, those near primary roads have 

higher Hispanic student fractions than other schools.

Figure 2 – Cumulative Distribution of Student Hispanic Percentages for Schools Near and Far from Major 

Roads

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0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

%Nonwhite or Hispanic Students

Percentile of Schools

Near Primary Roads

Near Secondary Roads

All Schools
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Analysis of Free and Reduced-Price Lunch Eligibility

To evaluate the socioeconomic status of students who attend schools within 200 meters of 

primary and secondary roads, EPA used SAS 9.1 to evaluate the number of students who are eligible for 

the U.S. Department of Agriculture’s free or reduced-price school lunch program. Children from families 

with incomes at or below 130 percent of the poverty level are eligible for free meals. Those with 

incomes between 130 percent and 185 percent of the poverty level are eligible for reduced-price

meals.8

 

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United States Department of Agriculture: Food and Nutrition Service, National School Lunch Program Fact Sheet. 

Obtained from: http://www.fns.usda.gov/cnd/Lunch/AboutLunch/NSLPFactSheet.pdf, September, 2010. For the 

period July 1, 2010, through June 30, 2011, 130 percent of the poverty level is $28,665 for a family of four; 185 

percent is $40,793.

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0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

%Hispanic students

Percentile of Schools

Near Primary Roads

Near Secondary Roads

All Schools
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Table 3 shows the number and percent of students that are eligible for free or reduced-price

school lunches out of the 49,136,240 students at all 99,804 U.S. schools, by number and percent of total 

students. 

Table 3: Number and Percent of Students Eligible for Free or Reduced-Price Lunch at all U.S. Schools

Free Lunch 

Eligible

ReducedPrice Lunch 

Eligible

Total Free or 

ReducedPrice Lunch 

Eligible

Number 

of 

Students

18,684,568 3,738,839 22,423,407

Percent 

of Total 38.03% 7.61% 45.64%

EPA also evaluated the number of students eligible for free or reduced-price school lunches at 

only the 23,978 schools within the 200 meter buffers of U.S. primary and secondary roads. Table 4 

shows the number and percent of students, by lunch program eligibility, at these schools, by road type.

Table 4: Number and Percent of Students Eligible for Free or Reduced-Price Lunch at U.S. Schools within 

200 meters of Primary and Secondary Roads, by Road Type

Free Lunch 

Eligible

ReducedPrice 

Lunch 

Eligible

Total Free 

or 

ReducedPrice 

Lunch 

Eligible

Primary 

Road

Number of 

Students 323,223 55,792 379,015

Percent of 

Total 39.81% 6.87% 46.68%

Secondary 

Road

Number of 

Students 3,587,928 732,779 4,320,707

Percent of 

Total 38.92% 7.95% 46.87%
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Primary 

and 

Secondary 

Roads

Number of 

Students 3,911,151 788,571 4,699,722

Percent of 

Total 38.99% 7.86% 46.85%

The data in Tables 3 and 4 shows that students eligible for the free and reduced-price lunch 

program are overrepresented at schools located within 200 meters of primary and secondary roads. 

The highlighted cells in Table 4 indicate that free and/or reduced-price lunch eligibility is 

overrepresented in the student population for the sets of schools within the 200 meter buffers of 

primary roads, secondary roads, and primary and secondary roads combined, as compared to the free 

and/or reduced-price lunch eligibility distribution of students attending all of the 99,804 schools in the 

U.S.9 For example, at schools located within 200 meters of a primary road or secondary road, 46.85% of 

students are eligible for either free or reduced-price lunches, whereas nationally, 45.64% of students are 

eligible for either free or reduced-price lunches. 

Figure 3 depicts the cumulative (percentile) distributions of the percentage of students eligible for 

free/reduced-price lunches for schools near primary and secondary roads, and for all schools. 

Consistent with the tabular data presented in Tables 1 and 2, schools near primary roads tend to have 

higher fractions of eligible students, though the association is inconsistent across the distribution. 

Notably, the majority of schools located near primary roads have student populations of which >50% are 

eligible for free or reduced price lunch.

Figure 3 – Cumulative Distribution of Percentage of Student Eligible for Free or Reduced-Price Lunches 

for Schools Near and Far from Major Roads

 

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The highlighted free and/or reduced-price lunch eligibility proportions in Table 4 were tested against the 

corresponding free and/or reduced-price lunch eligibility’s proportion in Table 3 to determine if the difference in 

the eligibility’s proportion in the observed populations (i.e., the free and/or reduced-price lunch eligibility

distributions for the schools within 200 meters of primary, secondary, and primary and secondary roads combined) 

and the whole U.S. population of schools is statistically significant. Using a chi-square goodness of fit test, the 

differences in the highlighted percentages in Table 4 and the corresponding percentages in Table 3 were all 

statistically significant (p < 0.0001).
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The data and results are presented in the attached Microsoft Excel workbook, “Schools Near 

Roads Analysis for the Tier 3 NPRM docket.” The first worksheet, ‘All U.S. Schools,’ lists each of the 

99,804 U.S. schools and its associated location and site information (school name, address, county, 

state, latitude, longitude, NCES assigned School ID) demographic data (the number of students who 

identify as American Indian/Alaskan Native; Asian/Pacific Islander; Black; Hispanic; White, non-Hispanic; 

Two or more Races), school lunch program eligibility data, and total enrollment data. The second 

worksheet, ‘Schools in 200m Buffers,’ lists each of the 23,978 schools within 200 meters of a primary or 

secondary road (1,649 are near primary roads and 22,329 are near secondary roads). The data identifies 

each school’s site information (school name, address, county, state, latitude, longitude, NCES assigned 

School ID) demographic data (the number of students who identify as American Indian/Alaskan Native; 

Asian/Pacific Islander; Black; Hispanic; White, non-Hispanic; Two or more Races), school lunch program 

eligibility data, and total enrollment data. The data also identifies the name of the road the school is 

within 200 meters of, whether that road is identified as a primary or secondary road, and the U.S. 

Census Bureau’s ID for the road segment. 

Summary

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%Students Eligible for Free/Reduced Price Lunch

Percentile of Schools

Near Primary Roads

Near Secondary Roads

All Schools
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On a population-wide basis, there are millions of students attending classes in locations likely to 

have poor air quality resulting from the emissions of vehicles on the nearby roads.

The analyses described above provide evidence that schools near major roads include student 

populations which have higher percentages of nonwhite racial minorities and of recipients of free or 

reduced-price lunches. These analyses suggest that children in these demographic groups experience 

worse air quality, and as such, have potential for elevated risks of adverse health outcomes.

Overall, this analysis indicates that nonwhite and low SES students are likely to experience 

significant benefit as a result of the proposed standards.