Number 368 March 2009

Traffic Safety Facts

Traffic Tech – Technology Transfer Series

U.S. Department of Transportation 1200 New Jersey Avenue SE., Washington, DC 20590

National Highway Traffic Safety Administration

The main goal of Safe Routes to School (SRTS) programs is to

increase children’s walking and biking to school. As the SRTS

program grew, there arose concern that a possible increase in

pedestrian and bicycle exposure from these programs could

result in an increase in child pedestrian and bicycle-related

crashes. Therefore, the goal of this study was to evaluate the

safety impact of SRTS programs in the United States. The

programs evaluated in this study were established prior

to the passage of the Safe, Accountable, Flexible, Efficient

Transportation Equity Act: A Legacy for Users (SAFETEALU), which sets guidelines for the establishment of SRTS

programs. As such, the programs studied are referred to as

“legacy SRTS” programs.

This study was conducted in two phases. Phase I examined

the feasibility of conducting the study by using secondary

source data and determining possible methods to conduct

a crash-based study. It was concluded from Phase I that a

definitive crash-based assessment of legacy SRTS program

effects was not possible. However, it was possible to conduct a preliminary crash analysis to indicate whether a more

detailed longitudinal study of the post-SAFETEA-LU SRTS

programs is needed. 

Both qualitative and quantitative data were collected in

Phase II. Researchers collected in-depth information on each

program included in the study. This information included

school calendars and bell times. A taxonomy was created

from this qualitative information and was used to structure

the crash data analysis. Crash data from NCSA’s State Data

System (SDS) was used for the analysis.

Overall, 130 legacy SRTS programs provided sufficiently

detailed data to be included in the study. Asubset of the program information was used together with SDS data to prepare case studies of the three States with the largest numbers

of programs in the study sample. Additional States could

not be used because they contained too few programs to support a stable analysis.

Evaluation of the Safety Benefits of Legacy 

Safe Routes to School Programs

Results

Some typical characteristics of these SRTS programs included

the following:

Elementary school programs predominated.

Programs had typically been in operation for five years

or less.

About half of the studied programs had been completed

while the other half were still ongoing.

Most programs were in urban and suburban locations.

Most of the programs used multiple E’s (engineering,

enforcement, education, encouragement, or evaluation),

but many of the high dollar value programs consisted

only of engineering interventions.

Highway safety considerations motivated the start of the

largest number of programs (the overall percentage motivated primarily by traffic safety concerns was 27.7%).

Crash data was analyzed using crash-involved pedestrians

and bicyclists as the primary unit of analysis. Crash-involved

pedestrians and bicyclists were examined as a function of

the age of the person involved and the location of the crash.

Location was divided into statewide and SRTS focus city/

county components. Victim age was divided into elementary school children (4 to 12 years old) and all other ages (0 to

3 years old and 13+ years old).

The data was standardized to simplify comparisons of a

series of greatly differing sizes and to maintain the anonymity of the States (a requirement when using SDS data). The

raw numbers of crashes for each year in each series were

divided by the raw number of crashes that occurred to the

same population subgroup in 1996, thus providing a standardized value for crashes each year in relationship to the

crashes that occurred in 1996. Crashes in 1996 were assigned

a value of 1.0. 

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TRAFFIC TECH is a publication to disseminate information about

traffic safety programs, including evaluations, innovative programs, and new publications. Feel free to copy it as you wish. If

you would like to receive a copy, contact Dr. Angela Eichelberger,

1200 New Jersey Avenue SE., NTI-130 Editor, fax 202-366-7394, e-mail: traffic.tech@dot.gov. Washington, DC 20590

To accomplish a statistical comparison among the various

series, linear regression equations were calculated for each

data series. These regressions first indicated if there was a

significant upward or downward trend in the various series.

The parameters of the regressions were also used to test

whether any significant trends were differential among the

series.

Because all three States showed similar patterns, charts from

State 1 will be used to illustrate the findings. Figure 1 shows

three series of pedestrian and bike crashes for children age 4

to 12 from 1996 to 2004. One series consists of crashes that

occurred in cities or counties with SRTS programs during

windows around school bell times when schools were in

session. Another series consists of all pedestrian and bike

crashes in State 1. The third series consists of pedestrian and

bicycle crashes that occurred within the State during school

travel times. The data show that pedestrian and bicycle

crashes involving elementary school children decreased

from 1996 to 2004.

Figure 1: State 1 crash-involved 4- to 12-year-old 

pedestrians and bicyclists

The results showed that crash-involved elementary school

children on the schooltrip wentdown significantly in allthree

States, both statewide and at the SRTS focus sites. Although

the State and SRTS focus site decreases were not significantly

different, the focus sites did show greater reductions than

the States as a whole. Over the same period, pedestrian and

bicyclist crash involvement of other ages and the involvement of 4- to 12-year-olds as passengers during the school

trip showed no consistent patterns.

Two series were created to examine crash-involved passengers 4 to 12 years old in order to serve as a potential measure

of mode shift. One series consists of crashes that occurred

in cities or counties with SRTS programs during windows

around school bell times when schools were in session. The

other series consists of crashes that occurred within the State

during school travel times. An increase in crash-involved

passengers in this age group could be indicative of more children riding in automobiles to school. The statewide series in

Figure 2 for crash-involved passengers 4 to 12 shows a trend

of increasing crash-involved passengers that peaks in 2001

and then starts a slight decline over the next few years. The

series for crash-involved passengers at the SRTS focus sites is

inconsistent with some years showing an increase in crashes

and others a decrease.

Figure 2: State 1 crash-involved 4- to 12-year-old 

passengers

Discussion

The results from this study reveal a consistent pattern of

declining pedestrian and bicycle crash involvements of

elementary school children over the years during which

legacy SRTS programs were implemented. This provides

strong support for a conclusion that legacy SRTS programs

were at least benign with respect to crashes. However, the

data reported from this study are not sufficient to determine

if SRTS programs can be credited with decreasing crash

involvements.

How to Order

For a copy of Evaluation of the Safety Benefits of Safe Routes 

to School Programs, write to the Office of Behavioral Safety

Research, NHTSA, NTI-130, 1200 New Jersey Avenue SE.,

Washington DC 20590, send a fax to 202-366-7096, or download from http://www.nhtsa.dot.gov. Marvin Levy, Ph.D.,

and Jenny Percer, Ph.D., were the project officers.

0.75

0.50

0.25

0.00

Ped/Bike Ages 4-12 for SRTS Sites, School Calendar Dates, 

Days & Times

199619971998199920002001200220032004

1.00

1.25

1.50

Standardized Values

(19996 Base)

Ped/Bike Ages 4-12 Statewide All Dates and Times

Ped/Bike Ages 4-12 Statewide, 6:45a.m.-9:15a.m. and

1:30p.m.-4:30p.m. Mon.-Fri.

0.75

0.50

0.25

0.00

Passengers Ages 4-12 for SRTS Sites, School Calendar

Dates, Days & Times

199619971998199920002001200220032004

1.00

1.25

1.50

Standardized Values

(19996 Base)

Passengers Ages 4-12 Statewide, 6:45a.m.-9:15a.m. and 

1:30p.m.- 4:30p.m. Mon.-Fri.