465 CALIFORNIA STREET, SUITE 810
SAN FRANCISCO, CA 94104
CALIFORNIA SPEEDING AND AGGRESSIVE DRIVING STUDY 2019
DATA ANALYSIS AND
COMPARISON WITH 2015 SURVEY DATA RESULTS
Conducted on Behalf of
The California Highway Patrol (CHP) and Safe Transportation
Research and Education Center - University of California,
Berkeley (SafeTREC)
AUGUST 2019
D R A F T SPEEDING AND AGGRESSIVE DRIVING SURVEY 2019 DATA ANALYSIS 2
TABLE OF CONTENTS
SUMMARY OF FINDINGS ............................................................................................................................... 3
I. INTRODUCTION .......................................................................................................................................... 4
II. METHODS .................................................................................................................................................. 4
SAMPLE FRAME ............................................................................................................................................. 4
DIVISION VARIABLE ....................................................................................................................................... 4
III. RESULTS .................................................................................................................................................... 6
SURVEY COMPLETES BY DIVISION AND COUNTY .......................................................................................... 6
RESPONDENT DEMOGRAPHICS .................................................................................................................... 7
DRIVING FREQUENCY BY DIVISION (Q1) ....................................................................................................... 8
SPEED DIFFERENTIAL ON FREEWAYS (Q2, Q3) ............................................................................................. 8
DEFINITION AND PERCEPTION OF “SPEEDING” ON FREEWAYS (Q4, Q5) ..................................................... 9
NEGATIVE CONSEQUENCES OF “SPEEDING” ON FREEWAYS (Q6, Q7, Q8) ................................................. 10
SPEED DIFFERENTIAL ON RESIDENTIAL ROADS (Q9) .................................................................................. 11
NEGATIVE CONSEQUENCES OF “SPEEDING” ON RESIDENTIAL ROADS (Q10) ............................................ 11
PERCEPTION OF “SPEEDING” ON RESIDENTIAL ROADS (Q11) .................................................................... 13
DEFINITION AND PERCEPTION OF “AGGRESSIVE DRIVING” (Q12, Q13, Q14) ............................................ 13
NEGATIVE CONSEQUENCES OF “AGGRESSIVE DRIVING” (Q15) ................................................................. 16
SPEEDING AND AGGRESSIVE DRIVING (Q16) .............................................................................................. 16
D R A F T SPEEDING AND AGGRESSIVE DRIVING SURVEY 2019 DATA ANALYSIS 3
SUMMARY OF FINDINGS
Driving frequency
In 2019, majority of drivers surveyed, 58.1%, said that they drive on a freeway “6-7 days a week” a
significant 7.8% increase since 2015 (Table Q1_1).
Speed differential on freeways
Over two-thirds of drivers, 68.4%, have driven 10 miles per hour over the speed limit on freeways,
a decrease of 4.2% from 2015 (Table Q2_1).
19.5% of drivers have driven 20 miles per hour over the speed limit on freeways, compared to
22.7% in 2015. (Table Q3_1).
Definition and perception of speeding on freeways
Similar to 2015, 46.0% of drivers define speeding as “Going faster than speed limit” (Table Q4_2).
22.3% of Northern and Golden Gate region drivers state speeding to be “Not a problem at all”,
which was significantly higher than the perception in the other three regions, which ranged from
4.2% to 13.0% (Table Q5_1).
Negative consequences of speeding on freeways
32.1% of all respondents have seen a crash caused by speeding drivers in the past 12 months on
California freeways, compared to 25.2% in 2015, a significant increase of 6.9% since 2015 (Table
Q6_1).
30.8% of all drivers surveyed have received a speeding ticket on a California freeway (Table Q6_1).
Drivers in the Inland and Border region and the Northern and Golden Gate region reported
significantly higher instances of being ticketed than the Coastal and Southern region (Table Q7_1).
Speeding differential on residential roads
23.6% of drivers have driven 10 miles per hour over the speed limit on residential roads, a
significant 6.4% decrease from 2015 (Table Q9_1).
87.5% of drivers in the Inland and Border regions have not observed a crash by a speeding driver
on a residential street, which is significantly less often than the other regions (Table Q10_1).
In 2019, 76.4% of all drivers believe that speeding on residential roads is a “Very big problem” or
“Somewhat of a problem”, compared to 81.0% of all drivers in 2015, a significant 4.6% decrease
(Table Q11_1).
Perception of “aggressive driving”
All drivers interpret “aggressive driving” as “Failing to yield the right of way”, except drivers in the
Northern and Golden Gate region, who stated “Making frequent lane changes” as indicative of
aggressive driving (Table Q12_3).
Negative consequences of aggressive driving
33.2% confirmed that they have witnessed a crash involving aggressive driving behavior,
compared to 27.3% of drivers in 2015, a significant increase of 5.9% (Table Q15_1).
D R A F T SPEEDING AND AGGRESSIVE DRIVING SURVEY 2019 DATA ANALYSIS 4
I. INTRODUCTION
The Speeding and Aggressive Driving Study 2019 report describes the analysis results of second wave of a
statewide California Public Opinion Survey on driver perceptions on speeding and aggressive driving on
California roadways. The first wave of the Speeding and Aggressive Driving Study was implemented in
2015 and repeated with an updated sample frame for the 2019 wave. The study was conducted by Ewald
& Wasserman Research Consultants (E&W) for the California Highway Patrol (CHP) and the Safe
Transportation Research and Education Center (SafeTREC) at the University of California, Berkeley.
Objective was the surveying of a cross-sectional representative sample of California drivers and their
perceptions and behaviors related to speeding and aggressive driving. Using in-person surveys at selected
gas stations with an electronic data collection tool resulted in 1,526 completed intercept surveys in 21
selected counties and 67 site locations throughout the State of California. Survey data was collected from
randomly selected California adult drivers in English or Spanish during the months of July and August,
2019.
II. METHODS
SAMPLE FRAME
The sample frame for the Speeding and Aggressive Driving Study 2019 was created in a multi-stage
proportional random site selection based on the Daily Vehicle Miles Traveled (DVMT) on California
roadways, using DVMT by county as the primary sampling units. The DVMT information was derived from
the California Department of Transportation’s Highway Performance Monitoring System (HPMS) 2017
California Public Road Data. The maintained daily vehicle miles traveled by jurisdictions and by county
were summarized to create the overall main sample frame for the site selection.
Next, all counties in the State of California accounting for less than 2.0% each of the total DVMT in the
State were excluded. In this process, 37 of California’s 58 counties were removed, leaving the sample
frame with 21 counties and jurisdictions.
DIVISION VARIABLE
The geographic segmentation of the State of California for this data collection included four divisions,
based on the CHP geographical organization of California counties and included “Northern and Golden
Gate”, “Valley and Central”, “Coastal and Southern”, and the “Inland and Border” divisions including the
counties as listed in Table D1.
Table D1. Four geographic divisions and respective counties
Northern and Golden
Gate
Valley and Central Coastal and Southern Inland and Border
Alameda
Stanislaus
Monterey
Orange
San Francisco
Fresno
Ventura
Riverside
Santa Clara
Tulare
Los Angeles
San Diego
San Mateo
Kern
--
San Bernardino
Solano
Sacramento
--
--
Sonoma
San Joaquin
--
--
D R A F T SPEEDING AND AGGRESSIVE DRIVING SURVEY 2019 DATA ANALYSIS 5
Contra Costa
Placer
--
--
The included counties accounted for 87.3% of the total California DVMT. The percentage of DVMT each
county within a division contributed to that division, as well as the percentage of county-DVMT of the
total statewide DVMT of included counties is shown in Table D2.
Also shown are the number of targeted intercepts by county, which were calculated proportionally as the
percentage of DMVT that county contributed to the statewide total of DVMT of all counties included.
Table D2 also includes the number of actual completes per county and division.
Table D2. Four geographic divisions and DMVT of included counties
% OF TOTAL
% OF DVMT
ACTUAL
Inland and Border Division
DIVISION
OF STATE
COMPLETES
Orange
27.7%
9.2%
140
Riverside
20.8%
6.9%
111
San Diego
29.8%
9.9%
144
San Bernardino
21.7%
7.2%
113
COMBINED DIVISION TOTAL
100.0%
33.1%
497
508
% OF TOTAL
% OF DVMT
ACTUAL
Valley and Central Division
DIVISION
OF STATE
COMPLETES
Stanislaus
8.7%
1.5%
22
Fresno
17.8%
3.0%
46
Tulare
7.9%
1.3%
19
Kern
18.4%
3.1%
48
Sacramento
26.1%
4.4%
69
San Joaquin
13.5%
2.3%
35
Placer
7.5%
1.3%
19
COMBINED DIVISION TOTAL
100.0%
16.7%
250
258
% OF TOTAL
% OF DVMT
ACTUAL
Coastal and Southern Division
DIVISION
OF STATE
COMPLETES
Monterey
4.2%
1.3%
19
Ventura
7.4%
2.3%
35
Los Angeles
88.4%
27.0%
405
COMBINED DIVISION TOTAL
100.0%
30.6%
458
459
% OF TOTAL
% OF DVMT
ACTUAL
Northern and Golden Gate
Division
DIVISION OF STATE COMPLETES
COMPLETES
Alameda
25.9%
5.1%
77
San Francisco
6.0%
1.2%
26
Santa Clara
25.7%
5.0%
76
San Mateo
11.6%
2.3%
35
Solano
8.4%
1.7%
29
Sonoma
7.5%
1.5%
22
Contra Costa
14.9%
2.9%
36
D R A F T SPEEDING AND AGGRESSIVE DRIVING SURVEY 2019 DATA ANALYSIS 6
COMBINED DIVISION TOTAL
100.0%
19.6%
294
301
STATEWIDE
--
100.0%-
1,500
1,526
III. RESULTS
The results in this report are based on a total of 1,526 completed intercept surveys with adult drivers,
distributed among the four defined division within the state of California. All data presented includes only
valid answers and excludes “Skipped” answers, which are the result of respondents wishing to skip a
question or respondents not knowing an answer. The valid percentage of responses therefore differs for
each question due to the number of valid answers given to a particular question and is reflected in the
total number of completes listed in each table. Due to rounding to one decimal point, some percentages
presented do not always add up to the exact value of 100.0%.
Overall, 1,526 vehicle drivers were intercepted for the study, resulting in an overall confidence interval
of +/- 2.51, at a confidence level of 95%.
Analysis note: All significances mentioned refer to a two-tailed probability with the resulting value of “z”
and a p value indicating the difference between the listed (and assumed independent) proportion of
drivers interviewed in 2015 and 2019. Where applicable, calculations were adjusted for pairwise
comparisons using the Bonferroni correction. Significant findings are highlighted in the tables and
described in the text.
Analysis note: For multiple choice questions, a respondent may give more than one answer. The results
shown, unless indicated otherwise, are calculated with the total number of answers given by all
respondents as the denominator, for a column adding up to 100.0% and excluding responses of “Skip”.
SURVEY COMPLETES BY DIVISION AND COUNTY
The completed intercepts by geographic division shows 301 completes in the “Northern and Golden Gate”
Division, 258 in “Valley and Central”, 459 in “Coastal and Southern”, and the 508 in the “Inland and
Border” division.
Table D3. Completed intercepts by division
Division # completes
%
completes
Northern and Golden Gate
301
19.7%
Valley and Central
258
16.9%
Coastal and Southern
459
30.1%
Inland and Border
508
33.3%
Total
1,526
100.0%
Table D4 shows the number of completed intercept surveys by county and division.
D R A F T SPEEDING AND AGGRESSIVE DRIVING SURVEY 2019 DATA ANALYSIS 7
Table D4. Completed intercepts by division and county
County
Northern and
Golden Gate
Valley and
Central
Coastal and
Southern
Inland and
Border
Stanislaus
--
22
--
--
Fresno
--
46
--
--
Tulare
--
19
--
--
Kern
--
48
--
--
Sacramento
--
69
--
--
San Joaquin
--
35
--
--
Placer
--
19
--
--
Monterey
--
--
19
--
Ventura
--
--
35
--
Los Angeles
--
--
405
--
Alameda
77
--
--
--
San Francisco
26
--
--
--
Santa Clara
76
--
--
--
San Mateo
35
--
--
--
Solano
29
--
--
--
Sonoma
22
--
--
--
Contra Costa
36
--
--
--
Orange
--
--
--
140
Riverside
--
--
--
111
San Diego
--
--
--
144
San Bernardino
--
--
--
113
Total
301
258
459
508
RESPONDENT DEMOGRAPHICS
The age and gender distribution of intercept respondents is shown in Table R1. The age variable was
provided by the respondent; gender was coded by the field staff. Overall, the distribution of age and
gender is comparable among the California regions.
Table R1. Age and gender distribution by geographic regions
Gender Age Group
Northern and
Golden Gate
Valley and
Central
Coastal and
Southern
Inland and
Border
Total
Male
18-24
12.4%
15.2%
15.1%
9.4%
12.7%
25-34
33.2%
21.3%
25.1%
28.1%
27.2%
35-44
21.8%
15.9%
18.3%
25.9%
21.0%
45-54
16.3%
22.6%
24.3%
21.6%
21.3%
55-69
12.9%
19.5%
13.5%
12.6%
14.2%
70 or older
3.5%
5.5%
3.6%
2.5%
3.6%
Total
100.0%
100.0%
100.0%
100.0%
100.0%
Female
18-24
11.1%
19.8%
19.4%
9.3%
14.4%
25-34
32.2%
15.4%
24.0%
27.0%
25.0%
35-44
18.9%
20.9%
17.9%
24.8%
21.1%
45-54
22.2%
25.3%
15.3%
20.4%
19.7%
55-69
7.8%
9.9%
18.9%
15.5%
14.6%
70 or older
7.8%
8.8%
4.6%
3.1%
5.1%
Total
100.0%
100.0%
100.0%
100.0%
100.0%
D R A F T SPEEDING AND AGGRESSIVE DRIVING SURVEY 2019 DATA ANALYSIS 8
DRIVING FREQUENCY BY DIVISION (Q1)
The driving frequency question asked drivers how often they drove on a freeway in California with the
answering options provided as outlined in Table Q1_1. The majority of answers stated “6-7 days a week”,
which was given by 58.1% of respondents. In comparison to 2015, the increase of 7.8% of driving “6-7
days a week” is significant (p<0.00).
Table Q1_1. “About how often do you drive on a freeway in California?” by division
Q1
Northern and
Golden Gate
Valley and
Central
Coastal and
Southern
Inland and
Border
Total
2019
Total
2015
6-7 days a week
58.8%
48.8%
52.0%
67.8%
58.1%
50.3%
3-5 days a week 19.3% 22.9% 28.0% 21.9%
23.4%
28.9%
1-2 times a week
14.0%
22.9%
11.9%
7.3%
12.6%
13.7%
Less than once a
week
8.0% 5.4% 8.1% 3.0% 5.9% 7.1%
Total 100.0% 100.0% 100.0% 100.0% 100% 100.0%
SPEED DIFFERENTIAL ON FREEWAYS (Q2, Q3)
Overall, 68.4% of all drivers stated to drive 10 or more miles over the speed limit while driving on a
freeway, about 4.2% fewer drivers compared to 2015 (p=0.01, Table Q2_1). The differences between
California regions in driving 10 miles over the speed limit in freeways range from 72.5% in the Northern
and Golden Gate region to 65.4% in the Coastal and Southern region, but the difference is not significant.
Table Q2_1. “Thinking about driving on a freeway, do you ever drive 10 miles over the speed limit?” by
division
Q2
Northern and
Golden Gate
Valley and
Central
Coastal and
Southern
Inland and
Border
Total
2019
Total
2015
Yes
72.5%
67.8%
65.4%
69.0%
68.4%
72.6%
No
27.5%
32.2%
34.6%
31.0%
31.6%
27.4%
Total
100.0%
100.0%
100.0%
100.0%
100%
100.0%
In response to the question if drivers ever drove 20 miles per hour over the speed limit on freeways,
19.5% stated that they did, ranging from 14.7% of drivers in the Inland and Border area to 23.5% of
Northern and Golden Gate region drivers. Inland and Border region drivers drive significantly less often 20
miles over the speed limit on freeways compared to drivers in the Northern and Golden Gate and the
Coastal and Southern region (p<0.05).
In comparison to 2015, overall significantly fewer drivers (19.5% in 2015 compared to 22.7% in 2015, a
3.2% reduction, p<0.05) drive 20 miles over the speed limit on freeways (Table Q3_1).
Table Q3_1. “Still thinking about driving on a freeway, do you ever drive 20 miles over the speed limit?”
by division
Q3
Northern and
Golden Gate
Valley and
Central
Coastal and
Southern
Inland and
Border
Total
2019
Total
2015
Yes
23.5%
19.0%
22.5%
14.7%
19.5%
22.7%
No
76.5%
81.0%
77.5%
85.3%
80.5%
77.3%
Total 100.0% 100.0% 100.0% 100.0% 100% 100.0%
D R A F T SPEEDING AND AGGRESSIVE DRIVING SURVEY 2019 DATA ANALYSIS 9
DEFINITION AND PERCEPTION OF “SPEEDING” ON FREEWAYS (Q4, Q5)
All drivers were asked to state their perception and the meaning of the term “speeding” in a multiple-
choice question. The answers, including open-ended comments are shown in Table Q4_1. All provided
open-ended answers were coded into additional categories and are highlighted in the table below.
The answering option “Going so fast that it is unsafe” was amended to “Going so fast that it is
unsafe/recklessness” to include open-ended comments stating reckless and dangerous driving.
Table Q4_1. “In your opinion, what does “speeding” mean? “answering options
Going faster than speed limit
Going faster than the rest of the traffic
Going so fast that it is unsafe
Other
Breaking traffic laws
More than 5mph over speed limit
More than 10mph over speed limit
More than 15mph over the speed limit
More than 20mph over the speed limit
Driving at any speed over 60mph
The combined responses by region and the comparison to the 2015 data are shown in Table Q4_2.
Similarly to the 2015 findings, the most prevalent opinion on the meaning of the term “speeding” given
was “Going faster than speed limit”, with 46.0% of all answers, ranging from 43.1% in “Northern and
Golden Gate” to 56.4% in the “Coastal and Southern” division.
Table Q4_2. “In your opinion, what does “speeding” mean?“ by division
Q4
Northern and
Golden Gate
Valley and
Central
Coastal and
Southern
Inland and
Border
Total
2019
Total
2015
Going faster than
speed limit
43.1% 45.2% 56.4% 40.5% 46.0% 47.4%
Going faster than
the rest of the traffic
19.4% 23.7% 15.0% 27.8% 22.3% 16.9%
Going so fast that it
is unsafe/
recklessness
19.4% 23.1% 17.1% 29.4% 23.5% 22.9%
Other
5.2%
1.2%
4.2%
0.8%
2.5%
1.8%
Breaking traffic laws
0.0%
0.0%
0.2%
0.4%
0.2%
1.0%
More than 5mph
over speed limit
1.5% 1.6% 0.9% 0.0% 0.7% 1.7%
More than 10mph
over speed limit
7.4% 2.8% 1.8% 0.4% 2.2% 3.6%
More than 15mph
over the speed limit
0.9% 1.6% 0.4% 0.0% 0.5% 0.8%
More than 20mph
over the speed limit
0.6% 0.9% 0.9% 0.1% 0.5% 1.9%
Driving at any speed
over 60mph
2.5% 0.0% 3.2% 0.7% 1.5% 2.1%
Total
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
D R A F T SPEEDING AND AGGRESSIVE DRIVING SURVEY 2019 DATA ANALYSIS 10
The subsequent question asked drivers about their perception of speeding causing problems on California
freeways, with the results by division shown in Table Q5_1. Overall, 73.3% of respondents stated that
speeding is a “Very big problem”, or “Somewhat of a problem”, similarly to the 72.0% of drivers in 2015.
There are some differences in the distribution of answers between the regions. A total of 22.3% of
Northern and Golden Gate region drivers state speeding to be “Not a problem at all”, which was
significantly higher than the perception in the other three regions (ranging from 4.2% to 13.0%, p=0.00).
Table Q5_1. “On California freeways do you think speeding is a…” by division
Q5
Northern and
Golden Gate
Valley and
Central
Coastal and
Southern
Inland and
Border
Total
2019
Total
2015
Very big problem
25.3%
26.4%
33.6%
24.5%
27.7%
37.0%
Somewhat of a
problem
34.9% 43.3% 40.8% 57.1% 45.6% 35.0%
A small problem
17.5%
17.3%
17.1%
14.2%
16.3%
15.6%
Not a problem at all
22.3%
13.0%
8.5%
4.2%
10.5%
12.4%
Total 100.0% 100.0% 100.0% 100.0% 100% 100.0%
NEGATIVE CONSEQUENCES OF “SPEEDING” ON FREEWAYS (Q6, Q7, Q8)
A total of 32.1% of all drivers stated that they have seen a crash caused by speeding drivers in the past 12
months on California freeways, compared to 25.2% of drivers asked in 2015 (Table Q6_1). The increase of
6.9% since 2015 of drivers having witnessed a crash caused by speeding is significant (p=0.00).
There are no significant differences between regions on that observation.
Table Q6_1. “In the past 12 months, have you witnessed a crash that involved a vehicle driver who you
think was speeding on a freeway?” by division
Q6
Northern and
Golden Gate
Valley and
Central
Coastal and
Southern
Inland and
Border
Total
2019
Total
2015
Yes
32.7%
28.9%
36.0%
30.1%
32.1%
25.2%
No
67.3%
71.1%
64.0%
69.9%
67.9%
74.8%
Total
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
Combined, 30.8% of drivers surveyed stated to have received a speeding ticket on a California freeway,
ranging from 22.7% in the Coastal and Southern region compared to 37.4% in the Inland and Border
region and 32.0% in the Northern and Golden Gate region – a significant difference between the
geographic areas (p=0.00, Table Q7_1). In contrast, there has not been a significant change in the amount
of tickets received since 2015.
Table Q7_1. “Have you ever received a speeding ticket on a California freeway?” by division
Q7
Northern and
Golden Gate
Valley and
Central
Coastal and
Southern
Inland and
Border
Total
2019
Total
2015
Yes
32.0%
30.7%
22.7%
37.4%
30.8%
32.8%
No
68.0%
69.3%
77.3%
62.6%
69.2%
67.2%
Total 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%
Respondents who have received a speeding ticket on a California freeway were asked how much over the
speeding limit the officer told them they were driving. The responses were converted into actual mileage,
D R A F T SPEEDING AND AGGRESSIVE DRIVING SURVEY 2019 DATA ANALYSIS 11
with ranges provided coded as the mid-point of the provided range, and “Don’t know” answers were
excluded from analysis (Table Q8_1).
Table Q8_1. “How much over the speed limit did the officer say you were traveling?” by division
Q8
Northern and
Golden Gate
Valley and
Central
Coastal and
Southern
Inland and
Border
Total
2019
Total
2015
Number of cases
88
73
72
136
369
495
Mean 15.4 16.1 12.5 14.6 14.7 15.2
Median
13.0
15.0
10.0
15.0
15.0
15.0
Minimum
5
6
5.
10
5
2
Maximum
55
60
30
30
60
45
SPEED DIFFERENTIAL ON RESIDENTIAL ROADS (Q9)
Drivers were asked if they ever drive 10 miles over the speed limit on residential roads, and 23.6% of all
respondents stated that they have, ranging from 20.5% in the Northern and Golden Gate regions to 27.9%
in the Valley and Central region, but without significant differences between the geographic areas.
The comparison between 2019 and 2015 results however show a 6.4% decrease in the frequency of
driving 10 miles over the speed limit on residential roads (significant at p=0.00, Table Q9_1).
Table Q9_1. “Thinking about these residential roads, do you ever drive 10 miles over the speed limit?”
by division
Q9
Northern and
Golden Gate
Valley and
Central
Coastal and
Southern
Inland and
Border
Total
2019
Total
2015
Yes
20.5%
27.9%
25.8%
21.1%
23.6%
30.0%
No
79.5%
72.1%
74.2%
78.9%
76.4%
70.0%
Total 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%
NEGATIVE CONSEQUENCES OF “SPEEDING” ON RESIDENTIAL ROADS (Q10)
All intercepted drivers were also asked if they ever witnessed a crash involving a speeding driver on a
residential road, and 20.4% of drivers confirmed this, a comparable finding to the 2015 survey results.
A comparison of the four geographic regions shows that 87.5% of drivers in the Inland and Border region
have not observed a crash by a speeding driver on a residential street, which is significantly less often
compared to all other regions (p=0.00, Table Q10_1).
Table Q10_1. “In the past 12 months, have you witnessed a crash that involved a vehicle driver who was
speeding on a residential road?” by division
Q10
Northern and
Golden Gate
Valley and
Central
Coastal and
Southern
Inland and
Border
Total
2019
Total
2015
Yes
29.6%
20.7%
23.2%
12.5%
20.4%
19.9%
No
70.4%
79.3%
76.8%
87.5%
79.6%
80.1%
Total 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%
D R A F T SPEEDING AND AGGRESSIVE DRIVING SURVEY 2019 DATA ANALYSIS 12
D R A F T SPEEDING AND AGGRESSIVE DRIVING SURVEY 2019 DATA ANALYSIS 13
PERCEPTION OF “SPEEDING” ON RESIDENTIAL ROADS (Q11)
A total of 76.4% of all drivers believe that speeding on residential roads is a “Very big problem” or
“Somewhat of a problem”, compared to 81.0% of all drivers in 2015. This 4.6% decrease in the perception
of speeding on residential roads as a problem is significant at p=0.00.
The comparison between regions shows no differences in the perception of drivers for the combined
responses of “Very big problem” or “Somewhat of a problem”. However, individually looking at the “Very
big problem” responses and the “Somewhat of a problem” response does show some significant
differences between the four geographic areas, with the Inland and Border region drivers less frequently
stating that speeding on residential roads is a “Very big problem” compared to the other regions (p=0.00).
Table Q11_1. “On residential roads in California do you think speeding is a…” by division
Q11
Northern and
Golden Gate
Valley and
Central
Coastal and
Southern
Inland and
Border
Total
2019
Total
2015
Very big problem
47.4%
40.2%
37.3%
22.8%
34.9%
47.0%
Somewhat of a
problem
28.7% 35.2% 40.7% 52.9% 41.5% 34.0%
A small problem
16.0%
16.0%
18.9%
22.6%
19.1%
13.4%
Not a problem at all
7.8%
8.6%
3.1%
1.8%
4.5%
5.6%
Total 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%
DEFINITION AND PERCEPTION OF “AGGRESSIVE DRIVING” (Q12, Q13, Q14)
The question on the perceived definition of the term aggressive driving was asked in multiple choice
format with an added open-ended comment. The additionally coded open-ended comments are
highlighted in Table Q12_1.
Table Q12_1. “In your opinion, what does the term “aggressive driving” mean?” answering categories
Speeding
Tailgating
Making frequent lane changes
Failing to yield the right of way
Express frustration/Aggression/Impatience (incl. gestures)
Doing other things while driving (read, eat, talk/text on phone)
Other
Failing to signal lane change
Unsafe passing
(swerving, weaving, passing)
Failure to stop
(red lights, stop signs, etc.)
Reckless driving
Not paying attention
Selfishness/lacking respect for others
Unsafe, dangerous driving, risk taking
Between the 1,526 respondents a total of 3,313 responses were provided for the multiple-choice
question, including all answers that could be coded into the outlined answer categories. The most
frequently mentioned definition of aggressive driving was “Failing to yield the right of way”, which was
given by 679 drivers (46.4% of all drivers). The second most frequent answer was “Making frequent lane
changes”, which was a definition provided by 635 drivers (43.4%). The third most frequently identified
aggressive driving behavior was “Tailgating” with 605 drivers providing this answer (41.3%, Table Q12_2),
D R A F T SPEEDING AND AGGRESSIVE DRIVING SURVEY 2019 DATA ANALYSIS 14
Table Q12_2. “In your opinion, what does the term “aggressive driving” mean?” combined answers
Q12 combined
# of
answers
% of
answers
% of drivers
Failing to yield the right of way
679
20.5%
46.4%
Making frequent lane changes
635
19.2%
43.4%
Tailgating
605
18.3%
41.3%
Speeding
521
15.7%
35.6%
Express frustration/ Aggression/
Impatience
(incl. gestures))
339 10.2% 23.2%
Doing other things while driving
(read,
eat, talk/text on phone)
173 5.2% 11.8%
Other
135
4.1%
9.2%
Selfishness/lacking respect for others
72
2.2%
4.9%
Failing to signal lane change
59
1.8%
4.0%
Unsafe/dangerous driving, risk taking
40
1.2%
2.7%
Reckless driving
22
0.7%
1.5%
Unsafe passing
(swerving, weaving, passing)
15
0.5%
1.0%
Failure to stop (red lights, stop signs, etc.)
14
0.4%
1.0%
Not paying attention
4
0.1%
0.3%
Total
3,313
100.0%
226.3%
The combined answers to Q12 by geographic region are shown in Table Q12_3, with the most frequently
given answer in each division is highlighted. In all regions, except in the Northern and Golden Gate
division, “Failing to yield the right of way” was the most common response, with the highest percentage in
the “Inland and Border” division, accounting for 22.1% of all answers. By contrast, in the Northern and
Golden Gate division, “Failing to yield the right of way” was the second most common response, while
“Making frequent lane changes” was the most common definition of the term aggressive driving.
Table Q12_3. “In your opinion, what does the term “aggressive driving” mean?” by division
Q12
Northern and
Golden Gate
Valley and
Central
Coastal and
Southern
Inland and
Border
Failing to yield the right of way
16.5%
22.2%
19.5%
22.1%
Tailgating
15.2%
16.6%
15.9%
21.9%
Making frequent lane changes
17.5%
19.5%
18.7%
20.0%
Speeding
15.4%
15.5%
15.5%
16.1%
Express frustration/ Aggression/
Impatience (incl. gestures)
11.8% 5.8% 12.3% 10.0%
Doing other things while
driving (read, eat,
talk/text on phone)
2.3% 5.3% 4.7% 6.7%
Other
7.4%
6.4%
4.5%
1.5%
Failing to signal lane change
1.9%
2.6%
2.8%
0.7%
Selfishness/lacking respect for others
4.6%
2.7%
2.9%
0.5%
Unsafe/dangerous driving, risk taking
3.8%
1.5%
1.0%
0.2%
Failure to stop (red lights, stop signs, etc.)
1.3%
0.0%
0.5%
0.2%
Not paying attention
0.0%
0.0%
0.2%
0.2%
Unsafe passing (swerving, weaving, passing)
1.1%
1.3%
0.2%
0.0%
Reckless driving
1.1%
0.7%
1.3%
0.0%
Total 100.0% 100.0% 100.0% 100.0%
D R A F T SPEEDING AND AGGRESSIVE DRIVING SURVEY 2019 DATA ANALYSIS 15
The response to the follow-up question on how many drivers respondents see displaying “aggressive
driving behavior” in an average week, is shown in Table Q13_1. Overall, the mean number of drivers
showing “aggressive driving behavior” was 16.08 in an average week, ranging from 24.05 in the Northern
and Golden Gate region to 9.67 in the Inland and Border region.
Table Q13_1. “How many drivers do you see displaying one or more “aggressive driving behavior” in an
average week?” by division
Q13
Northern and
Golden Gate
Valley and
Central
Coastal and
Southern
Inland and
Border
Total
2019
Total
2015
Number of cases
285
232
193
374
1,084
1,570
Mean
24.1
16.7
15.9
9.7
16.1
15.2
Median
7.0
10.0
7.0
5.0
5.5
5.0
Minimum
0
0
1
0
0
0
Maximum
1,000
100
100
100
1,000
1,000
The type of specific aggressive driving behaviors by geographic region is shown in Table Q14_1 with the
most frequent answer per region highlighted. In the Northern and Golden Gate division, “Making
frequent lane changes” was the most frequently given response as to the specific behavior observed
among the aggressive driving, with 23.1% of all mentions. In all three other divisions, “Failing to yield the
right of way” was the most frequently mentioned aggressive behavior, with 26.8% of all answers by
drivers in the Valley and Central region, 24.5% of answers by Coastal and Southern division drivers and
22.3% of Inland Border drivers.
Table Q14_1. “What type of ‘aggressive driving’ or specific behavior do you typically observe in those
drivers?” by division
Q14
Northern
and Golden
Gate
Valley and
Central
Coastal and
Southern
Inland and
Border
Failing to yield the right of way
(cutting
others off)
19.8% 26.8% 24.5% 22.3%
Making frequent lane changes
23.1%
22.3%
18.8%
22.2%
Tailgating
17.1%
15.9%
14.7%
21.1%
Speeding
14.6%
15.0%
14.9%
16.7%
Express frustration/ Aggression/
Impatience
(incl. gestures)
11.1% 5.3% 11.7% 9.7%
Doing other things while driving
(read,
eat, talk/text on phone)
2.3% 7.1% 5.1% 6.5%
Other
4.9%
2.0%
5.0%
0.6%
Failing to signal lane change
2.5%
2.7%
2.6%
0.6%
Selfishness/lacking respect for others
0.8%
0.9%
0.9%
0.2%
Unsafe passing (swerving, weaving, passing)
1.9%
0.9%
0.5%
0.0%
Failure to stop (red lights, stop signs, etc.)
1.4%
0.4%
0.8%
0.0%
Reckless driving
0.0%
0.7%
0.5%
0.0%
Unsafe/dangerous driving, risk taking
0.4%
0.0%
0.0%
0.0%
Total
100.00%
100.00%
100.00%
100.00%
The observed aggressive driving behavior comparison between 2015 and 2019 is shown in Table Q14_2.
Overall, the distribution of answers is very comparable.
D R A F T SPEEDING AND AGGRESSIVE DRIVING SURVEY 2019 DATA ANALYSIS 16
Table Q14_2. “What type of ‘aggressive driving’ or specific behavior do you typically observe in those
drivers?” by division
Q14
Total
2019
Total
2015
Failing to yield the right of way
(cutting
others off)
23.2% 22.6%
Making frequent lane changes
21.4%
20.1%
Tailgating
17.7%
14.4%
Speeding
15.6%
16.3%
Express frustration/ Aggression/
Impatience (incl. gestures)
9.8% 12.9%
Doing other things while driving
(read,
eat, talk/text on phone)
5.5% 3.8%
Other
2.9%
3.6%
Failing to signal lane change
1.8%
2.3%
Selfishness/lacking respect for others
0.6%
1.6%
Unsafe passing (swerving, weaving, passing)
0.6%
1.2%
Failure to stop
(red lights, stop signs, etc.)
0.6%
1.1%
Reckless driving
0.2%
--
Unsafe/dangerous driving, risk taking
0.1%
--
Total
100.0%
100.0%
NEGATIVE CONSEQUENCES OF “AGGRESSIVE DRIVING” (Q15)
The response to the questions if respondents had witnessed a crash involving a driver displaying
aggressive behavior is shown in Table Q15_1. A total of 33.2% confirmed that they have witnessed a crash
involving aggressive driving behavior, compared to 27.3% of drivers in 2015, a significant increase of
observed crashes of 5.9% (p=0.00).
A comparison between regions reveals a difference in the frequency of having observed a crash due to an
aggressive driver reveals that Inland and Border drivers less frequently observed crashes compared to all
other regions. At the same time, Coastal and Southern drivers observe crashes more frequently than
drivers in all other regions (p=0.00).
Table Q15_1. “In the past 12 months, have you witnessed a crash that involved a vehicle driver who was
doing any of these behaviors?” by division
Q15
Northern and
Golden Gate
Valley and
Central
Coastal and
Southern
Inland and
Border
Total
2019
Total
2015
Yes
33.5%
34.4%
45.3%
21.8%
33.2%
27.3%
No
66.5%
65.6%
54.7%
78.2%
66.8%
72.7%
Total
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
SPEEDING AND AGGRESSIVE DRIVING (Q16)
The questions if speeding is a type of “aggressive driving” was confirmed by 73.5% of all drivers. Drivers in
the Coastal and Southern region however significantly more often consider speeding a type of aggressive
driving, with 84.1% of drivers compared to all other regions (p=0.00, Table Q16_1). The comparison to the
2015 findings are comparable.
D R A F T SPEEDING AND AGGRESSIVE DRIVING SURVEY 2019 DATA ANALYSIS 17
Table Q16_1. “Would you say that speeding is a type of “aggressive driving?” by division
Q16
Northern and
Golden Gate
Valley and
Central
Coastal and
Southern
Inland and
Border
Total
2019
Total
2015
Yes
70.1%
73.4%
84.1%
66.3%
73.5%
71.5%
No
29.9%
26.6%
15.9%
33.7%
26.5%
28.5%
Total
100.0%
100.0%
100.0%
100.0%
100%
100.0%