Summary of Traffic Stops Statistics
Burlington Police Department
The following report compiles and presents statistical summaries of traffic stops statistics drawn from the NC State Bureau of Investigation database to which each police agency reports their statistics each month. Data in this report cover the period of 2002 through 2020. The data exclude checkpoint stops because such stops are not recorded systematically. The data also include only the driver of the vehicle, excluding any passengers. Passenger information is generally recorded only in the event of an adverse outcome (e.g., search, arrest).
This report provides the following summary statistics:
First is a table providing summary statistics on numbers of stops, searches, contraband hits, and arrests, as well as relevant rates of these outcomes. This is followed by a series of graphics displaying department and officer level data.
| Summary of outcomes | State-wide | BPD |
|---|---|---|
| Stops | 24,980,776 | 136,568 |
| Traffic Safety Stops | 13,365,910 | 63,457 |
| Searches | 763,343 | 7,951 |
| Hits | 280,152 | 2,850 |
| Arrests | 500,040 | 5,823 |
| Arrest From Hit From Search | 105,784 | 1,351 |
| Consent Searches | 346,475 | 2,558 |
| Arrest From Hit From Consent Search | 20,759 | 137 |
| Probable Cause Searches | 264,963 | 2,899 |
| Arrest From Hit From Probable Cause Search | 54,326 | 690 |
| Percent Traffic Safety Stops | 53.50% | 46.47% |
| Search Rate Per Stop | 3.06% | 5.82% |
| Hit Rate Per Search | 33.48% | 32.00% |
| Arrest Rate Per Hit | 38.85% | 48.77% |
| Hit-and-Arrest Rate Per Search | 13.86% | 17.00% |
| Hit-and-Arrest Rate Per Probable Cause Search | 20.50% | 23.81% |
| Hit-and-Arrest Rate Per Consent Search | 5.99% | 5.36% |
| Arrest Rate Per Stop | 2.00% | 4.26% |
| Hit-and-Arrest Rate Per Stop | 0.42% | 0.99% |
Numbers at top of the table show raw values; numbers below are the percentages based on the numbers above.
Figure 1 shows the total number of stops per year from 2002-2020. Numbers range from approximately 4,000 (in 2020) to almost 12,000 (in 2014). There is a drop associated with the global pandemic in 2020.
Figure 2 shows the total number of traffic stops by race and gender from 2002-2020. For example, in 2002, roughly 33% of total traffic stops were of white males, roughly 18% of stops were of black males, roughly 10% were of black females, and roughly 20% were of white females. White drivers’ share of those stopped decreased over the timeframe, while both black males and females slightly increased as a proportion of total stops.
Figure 3. Percent of stops for “safety” purposes (speeding, stop sign, DUI, unsafe movement)
Figure 3 shows the percentage of traffic stops that are considered safety-related for each respective race and gender grouping, from 2002-2020. Safety-related spots are composed of stops due to speeding, stop sign violations, DWI, and unsafe movement. Stops for violations other than this are classified as non-safety related. These are composed of non-moving violations such as equipment violations and expired tags. For this reason, non-safety-related stops can be considered to be used as informal criminal investigations. Each race and gender group followed relatively similar trends across the time period. The disparity between categories is far greater in the first half of the time period. During the years 2002 to 2012, safety-related stops consistently make up 40% or less of black male drivers’ total stops, while the other race and gender categories typically have far greater percentages of safety related stops. In the years post 2012, the disparity between the categories lessens. Stops of black males are still the least frequently classified as safety-related, but the difference between these drivers and all other drivers is not as significant.Overall, black male consistently had the lowest percentage of their stops classified as safety-related. Black females typically had the second lowest percentage of safety related stops. White female drivers typically had the highest percentage of safety related stops.
Figure 4. Percent of stops resulting in a search, by race-gender category
Figure 4 shows the percent of traffic stops that result in a search for each respective race and gender grouping, from 2002-2020. The Figure indicates that most traffic stops do not result in a search. For all categories except black males, drivers were searched at less than a 10% rate across the time period. Black males were typically searched at the highest rate, typically at around 10% for a majority of the time frame. Search rates for white males ranged from 4 to 9% but consistently were around 5%. Female drivers had the lowest search rates, which were typically under 5%.
Figure 5. Percent of stops resulting in arrest, by race-gender category
Figure 5 shows the percent of traffic stops that result in an arrest for each respective race and gender grouping, from 2002-2020. Across the board, arrest rates are consistently very low, at below 10% for all categories across the time period. Black males are arrested at the highest rate in every year except 2006, and their arrest rate ranges from about 3 to 9%. Arrest rates for the other race and gender categories do not surpass 6%. White males were generally the second most arrested group, typically hovering around 4% with some variation in each direction. Female drivers were typically arrested at the lowest rates, and both black and white females have comparable rates across the time period.
Figure 6. Percent of searches resulting in contraband, by race-gender category
Figure 6 shows the percent of searches that result in the finding of contraband for each respective race and gender grouping, from 2002-2020. Note that there is no available data for white and black females, and the data for male drivers is also incomplete. Across the time period, there is a clear upward trend in contraband hits per search for both black and white males. In 2002, the rate of contraband discovery was at 20% and 28% for black and white males, respectively. In 2016, the last year with data available for both categories, those percentages increased to roughly 47% and 46%. Contraband hits in searches of black males also continued to increase for the remainder of the time period. The rate of contraband hit increased at a similar level across the time period for both categories, but there was significant variation from year to year.
Figure 7. Percent of searches resulting in contraband and arrest, by race-gender category
Figure 7 shows the percent of searches that resulted in the discovery of contraband and an arrest for each respective race and gender grouping, from 2002-2020. Note that in many instances, contraband hits do not lead to arrest due to it being found in small amounts. Also note that there is no available data for white and black females, and the data for male drivers is also incomplete. As seen in the Figure, the rate of contraband hit and arrest per search has steadily increased across the time period for all categories. In 2002, the rate of contraband discovery was at 10% and 12% for black and white males, respectively. In 2016, the last year with data available for both categories, those percentages increased to 27% for both categories . Contraband hits in searches of black males also continued to increase for the remainder of the time period. The rate of contraband hit increased at a similar level across the time period for both categories.
Figure 8. Percent of stops resulting in contraband and arrest, by race-gender category
Figure 8 shows the percent of stops that resulted in the discovery of contraband and an arrest for each respective race and gender grouping, from 2002-2020. The rates are very low for each category. White males, white females, and black females all have rates of less than 2% across the time period (with the exception of white males in 2020). The rates for black males are slightly higher but do not surpass 4%. Both black and white males also show an increase in contraband and arrest frequency across the time period. Stops of female drivers rarely lead to contraband and arrest. Typically, both categories have less than a 1% hit and arrest rate, with the sole exception of white females in 2016. Overall, for all race and gender categories, traffic stops are overwhelmingly unlikely to result in contraband and arrest
Figure 9. Black-White Ratio of search rates and arrest rates, for males
Figure 9 compares the search rate and arrest rate of black males and white males from 2002-2020. The search rate ratio is the search rate of black males divided by the search rate of white males, while the arrest rate ratio is the arrest rate of black males divided by the arrest rate of white males. A search rate ratio of 1.0 would indicate that black and white males are both searched in an equal percentage of their respective traffic stops. This similarly applies for the arrest rate ratios. Across the time period, the search rate ratio is consistently above 1, and is often much greater. This means that black males are searched much more frequently than white males across the time period. The search rate ratio peaked at about 2.7 in 2017, and typically ranged from 1.5 to 2.5. The arrest rate ratio also is consistently above 1, with the sole exception being in 2007. The arrest rate ratio does surpass the search rate ratio in certain instances (2005 and 2008) but typically is lower than the search rate ratio across the period. This means that in most years recorded, black males are arrested at a greater rate than white males, but not to the degree that they are disproportionately searched. The disparity between the two ratios is not as significant as in other comparable departments, however. In many instances, the ratios are quite close.
Figure 10. Black-White Ratio of search rates and arrest rates, for females
Figure 10 compares the search rate and arrest rate of black females and white females from 2002-2020. The search rate ratio is the search rate of black females divided by the search rate of white females, while the arrest rate ratio is the arrest rate of black females divided by the arrest rate of white females. A search rate ratio of 1.0 would indicate that black and white females are both searched in an equal percentage of their respective traffic stops. Across the time period, the search rate ratio ranges from 0.5 to 2.0. The arrest rate ratio also ranges from 0.5 to 2.0. The arrest rate ratio is typically similar to the search rate ratio for each given year, specifically in the latter half of the time period.
Figure 11. Summary of stops by hour over the week: Stops, percent safety-related, percent ending in citation, search, and arrest
Figure 11 displays the number of traffic stops, the percent of safety related stops, the percentage of drivers receiving a citation, the percentage of drivers searched, and the percentage of drivers arrested across the hours of the week. The Figure indicates that there is not much variation between the days of the week in regard to these measures, and instead shows that the variation is seen within the hours of the day. There are a few noticeable trends throughout the week, however. Stops occur most frequently on Friday and Saturday nights relative to other days at the same time. Both search and arrest rates are highest in the hours immediately following midnight on Wednesday and Saturday mornings.
Figure 12. Summary of stops by hour over the day: Stops, percent safety-related, percent ending in citation, search, and arrest
Figure 12 displays the number of traffic stops, the percent of safety related stops, and the percent of drivers searched, given a citation, and arrested by hour of day. There are a number of clear trends indicated in the Figure. The frequency of a traffic stop is lowest in the early hours of the morning, from around 4AM to 6AM. The number of traffic stops increases until 8AM, at which the frequency is similar until around 6PM. Traffic stops then increase until 9PM, at which point they begin to decrease until the early morning low.
The percentages of drivers searched and arrested both have a similar trend across the time of day. Drivers are both searched and arrested at the highest rate in the few hours after midnight, and then these rates of search and arrest decrease dramatically until 7AM. After 6AM, both rates are at extremely low percentages, and they slowly increase throughout the daytime and into the late night time hours.
The percentage of drivers receiving a citation follows an opposite trend of search and arrest rates. The rate of citations given is at its lowest from 9PM to 4AM, and then in the following hours steadily increases. The rate is significantly higher during daytime hours as compared to nighttime hours.
The percent of safety-related stops varies throughout the day, reaching its highest point from 5AM to 7AM and then steadily decreasing for the rest of the day. The rate is at its lowest from 7PM to midnight, at which point it begins to increase again.
Figure 13. Hourly breakdown of percent of stops by race-gender category
Figure 13 displays the share of overall stops represented by the respective race and gender categories by hour of day. The Figure indicates that black males are more likely to be stopped during the nighttime hours directly before and after midnight than they are to be stopped during the daytime. At 3AM, black males reach a high of 33% of those that are pulled over, and by 7AM their share of stops decreases to less than 15%, and stays at a lower proportion of stops throughout the daytime hours. White males, in contrast, make up a relatively consistent share of the overall traffic stops throughout the day, at around 25 to 30%, with the exception of 2AM to 3AM, when their share falls. Black females make up a relatively consistent share of traffic stops throughout the day, at roughly 15 to 20%. White females see a major uptick in their proportion of stops during the daytime hours, surpassing both black males and females.
Figure 14. Hourly breakdown of percent of stops related to traffic safety, by race-gender category
Figure 14 displays the percentage of stops that are for safety-related purposes for each race and gender category, by hour of the day. Safety-related purposes refer to traffic stops that are meant to prevent moving violations, and effectively keep the road safe. Stops that are not safety-related are often used for investigatory purposes, in which case the officer is generally seeking to conduct an informal criminal investigation of the driver. As evidenced in the Figure, black drivers are less likely to be stopped for safety-related purposes than white drivers throughout the course of the day. Black males in specific are susceptible to this, as for a majority of the daytime hours, black females have a percentage of safety-related stops comparable to white drivers. In turn, this means that black male drivers are more likely to be subjected to investigative stops that are not for moving violations. These stops are most common during the nighttime hours, when the percentage of safety-related stops is lowest for all categories. During this period of the day, black females rates of safety-related stops fall and grow comparable to black males. At almost any given hour of the day, black male drivers are more likely to be stopped for a non safety-related purpose than other drivers.
Figure 15. Hourly breakdown of percent of stops resulting in search, by race-gender category
Figure 15 displays the percentage of traffic stops which result in a search for each race and gender category, by hour of the day. Black males are searched at the highest rate regardless of time of day, but the time of day does significantly influence the rate at which they are searched. The rate of search during daytime hours is lower than nighttime hours. From 2AM to 7AM, search rates of black males drop from about 18% to about 4%, and it then steadily increases throughout the day. This pattern applies for all of the gender and race categories. During daytime hours, however, black males are still significantly more likely to be searched than other race and gender categories. Throughout the entire day, white males are searched at a lower rate than black males, and females, regardless of race, are typically searched at a lower rate than males (although during daytime hours, the rates for white males are comparable to female drivers and in a few instances lower). The Figure also indicates that a majority of stops do not result in a search regardless of race and gender category or time of day.
Figure 16. Hourly breakdown of percent of stops resulting in arrest, by race-gender category
Figure 16 displays the percentage of traffic stops which result in an arrest for each race and gender category, by hour of the day. For all categories, drivers are more likely to be arrested during nighttime hours, specifically the hours directly after midnight. Stops are most likely to result in an arrest at 2AM. All race and gender categories see an increase in rates of arrest in these early morning hours. At 2AM, all categories except black females are arrested at a similar rate of just below 15%. Throughout the remainder of the day, black males are more likely to be arrested than all other drivers. For the majority of the day, black males are arrested at about a 5% rate, while other categories are arrested in about 1 to 3% of stops. The Figure also indicates that a large majority of stops do not result in an arrest regardless of race and gender category or time of day.
Figure 17. Number of stops by officer
Figure 17 displays the distribution of number of stops by officer across the 2002-2020 time period. All officers displayed have over 100 traffic stops. 260 of the 315 officers included in the data have less than 500 traffic stops.
Figure 18. Percent black of drivers pulled over by officer
Figure 18 displays the percentage of stopped drivers that are black for individual officers, from 2002-2020. The distribution includes officers with greater than 100 traffic stops. For the median officer, 39.2% of stops are of black drivers, while black people only make up 27.7% of the population in the city. This means that a majority of officers are stopping black drivers at a rate disproportionate to their share of the population. This disparity between stop behavior and population data is often greater, with black drivers composing more than 50% of stops for a significant portion of officers. At the far right, the Figure shows that there are 38 officers whose mix of drivers stopped is more than 50% black.
Figure 19. Officer search rates by race
Figure 19 displays the search rates of individual officers for the given race and gender category. The criteria for an officer’s inclusion is 100 or more traffic stops, as well as at least 50 stops of the specified race and gender category, from 2002-2020. In the first graph, which displays search rates for black males, the median officer has a search rate of 9.8%. For white male drivers, the median officer has a search rate of 3.85%. This indicates that the median officer in Burlington is searching black males at a higher rate than they are searching white males.
Figure 20. Black-White Ratio of search rates by officer, for males
Figure 20 displays the distribution of black-white male search rate ratios across the officers which meet the criteria. The criteria for an officer’s inclusion is 50 traffic stops of both white males and black males, from 2002-2020. The “Black-white male search rate ratio” can be interpreted as an officer’s search rate of black male drivers divided by their search rate of white male drivers. An racially equitable outcome would therefore be 1, meaning that black and white male drivers are searched in an equal percentage of traffic stops. The median officer instead has a search rate ratio of 1.72, meaning that the median officer searches black male drivers at a higher rate than white male drivers. A significant number of officers have search-rate ratios that are much higher than the median, with a large portion searching black male drivers at 3 or more times the rate of white male drivers.
Figure 21. Search rate versus hit rate by officer
Figure 21 presents the hit rates and search rates of individual officers who meet the criteria. As evidenced by the low correlation, there is great variability in both the propensity of individual officers to search drivers and their success in finding contraband. One might expect that when officers have a high search rate but a low hit rate, that their supervisors would advise them to adjust their search rate in order to avoid so many fruitless searches. Similarly, for officers with low search rates but high hit rates, one might expect supervisors to instruct them to conduct more searches because they are being too cautious. Such a learning process would generate relative consistent hit rates; where officers are too high, they would be advised to do more searches, and where too low, to conduct fewer. The Figure shows clearly that this is not happening. Search and hit rates range from low to high, with a very low correlation between the two. Certain officers search drivers at extremely high rates but have very low hit rates, meaning that their threshold of suspicion is likely too low. Other officers search at a much lower rate and have very high hit rates, showing that their threshold of suspicion may be too high. Overall, the Figure shows that officers are not gravitating towards a single common range of hit rates. This suggests that the department does not seem to hold its officers to a common standard of search rate success. Rather, each officer decides for him or herself how aggressive to be in searching, with virtually no guarantee that more searches will lead to lower hit rates, or that fewer searches will be targeted on those most likely to have contraband.