Summary of Traffic Stops Statistics
Huntersville 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 | HPD |
|---|---|---|
| Stops | 24,980,776 | 118,037 |
| Traffic Safety Stops | 13,365,910 | 64,441 |
| Searches | 763,343 | 4,034 |
| Hits | 280,152 | 2,109 |
| Arrests | 500,040 | 41,932 |
| Arrest From Hit From Search | 105,784 | 527 |
| Consent Searches | 346,475 | 1,558 |
| Arrest From Hit From Consent Search | 20,759 | 83 |
| Probable Cause Searches | 264,963 | 2,332 |
| Arrest From Hit From Probable Cause Search | 54,326 | 381 |
| Percent Traffic Safety Stops | 53.50% | 54.59% |
| Search Rate Per Stop | 3.06% | 3.42% |
| Hit Rate Per Search | 33.48% | 43.13% |
| Arrest Rate Per Hit | 38.85% | 26.55% |
| Hit-and-Arrest Rate Per Search | 13.86% | 13.06% |
| Hit-and-Arrest Rate Per Probable Cause Search | 20.50% | 16.34% |
| Hit-and-Arrest Rate Per Consent Search | 5.99% | 5.33% |
| Arrest Rate Per Stop | 2.00% | 1.64% |
| Hit-and-Arrest Rate Per Stop | 0.42% | 0.45% |
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 just below 2,000 (in 2006) to almost 10,000 (in 2009).
Figure 2 shows the total number of traffic stops by race and gender from 2002-2020. For example, in 2002, roughly 49% of total traffic stops were of white males, roughly 10% of stops were of black males, roughly 5% were of black females, and roughly 27% were of white females. White males’ share of stops decreased by almost 20% over the time period. Black males and black females both significantly 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 negative trends across the time period. Unlike other comparable departments, however, the year-to-year change was significantly different for the different categories. For example, from 2005 to 2006, black males saw a roughly 10% increase in their percent of safety related stops, while all other groups saw a decrease. 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, with only few exceptions. White 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 6% rate across the time period. Black males were typically searched at higher rates, ranging from 3 to just above 12% across the time period. In most years, their search rate fell between 5 and 10%. This is significantly more often as the second most searched group, white males, who were searched in 2 to 6% of stops. Black males were searched at the highest rate in all but one year, 2004, when white males were searched at a marginally higher rate. White and black female drivers experienced similar levels of search rates over the first half of the time period, with both groups being searched at a lower rate than white and black males.
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 under 8% for all categories across the time period. Black males are arrested at the highest rate in every year except 2009 and 2015, and their arrest rate ranges from 1 to just below 8%, although the rate was often between 2 to 4%. Arrest rates for the other race and gender categories range from 0 to 4%. For female drivers specifically, arrest rates are at or below 2% across the entire time period. From 2004 to 2006, arrest data is missing and therefore is not displayed in the Figure.
Figure 6. Percent of stops resulting in contraband and arrest, by race-gender category
Figure 6 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 1% across the time period. The rates for black males have greater variation, and range from 0.1% of stops in 2014 to above 3% of stops in 2020 resulting in contraband and arrest. 2016 and 2020 are the only instances where the rate of contraband and arrest surpassed 2% for black males, however. Overall, for all race and gender categories, traffic stops are overwhelmingly unlikely to result in contraband and arrest. For 2002 and 2004-2006, contraband and arrest data is missing and therefore is not displayed in the Figure.
Figure 7. Black-White Ratio of search rates and arrest rates, for males
Figure 7 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, with the only exception being in 2004. This means that black males are searched much more frequently than white males across the time period. The search rate ratio peaked at above 4 in 2019, and typically ranged from 1 to 3. The arrest rate ratio also is consistently above 1, with exceptions in 2009 and 2015. The arrest rate ratio is relatively similar to the search rate ratio from 2002 to 2014 (with the exception of 2004-2006, when data was missing, and 2009, when the arrest rate ratio was significantly lower). Post 2014, the search rate ratio was typically higher than the arrest rate ratio, with the exception of 2020. From 2004 to 2006, arrest data is missing and therefore there is no arrest rate ratio for these years.
Figure 8. Black-White Ratio of search rates and arrest rates, for females
Figure 8 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 about 0 to just above 2. The arrest rate ratio ranges from 0.3 to just below 2. Both ratios fluctuate greatly on a yearly basis, with no clear pattern emerging. From 2014 to 2018, the search rate ratio was significantly higher than the arrest rate ratio. However, in 2019 and 2020, the ratios were almost identical.
Figure 9. Summary of stops by hour over the week: Stops, percent safety-related, percent ending in citation, search, and arrest
Figure 9 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 at the lowest rate on Saturday and Sunday during the daytime hours. Search rates are lowest on early Tuesday and Saturday morning as compared to the rest of the week at the same time. Arrest rates are higher in the very early morning on Wednesday, Friday, and Sunday, as compared to the same time on other days.
Figure 10. Summary of stops by hour over the day: Stops, percent safety-related, percent ending in citation, search, and arrest
Figure 10 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 3AM to 6AM. The number of traffic stops increases dramatically until 8AM, at which the frequency is similar until around 10PM, with a few minor changes throughout the daytime. The frequency of stops then begins to drop again until the low point in the early morning.
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 from 4AM to 6AM. After 6AM, the rate of both search and arrest is at extremely low percentages, and these rates then slowly increase for the remainder of the day.
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 5AM. The rate then sharply increases from 5AM to 7AM, and remains high for the remainder of the day, slowly decreasing until nighttime. 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 at 7AM, and then decreasing until 11AM. After 11AM, the rate of safety-related stops increase slightly, staying at a marginally elevated level until 5PM. Safety-related stops then decrease and are maintained at very low rates until they begin to increase at 4AM.
Figure 11. Hourly breakdown of percent of stops by race-gender category
Figure 11 displays the share of overall stops represented by the respective race and gender categories by hour of day. The Figure indicates that white males make up the highest percentage of stops across the day, at roughly 40% throughout the day. The Figure also 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 23% of those that are pulled over, and by 7AM their share of stops decreases to 10%, and stays at a lower proportion of stops throughout the daytime hours. Black females make up a relatively consistent share of traffic stops throughout the day, at around 10%. White females see a significant uptick in their proportion of stops during the daytime hours, going from at or below 20% during the nighttime hours to about 30% during the daytime.
Figure 12. Hourly breakdown of percent of stops related to traffic safety, by race-gender category
Figure 12 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 males are much less likely to be stopped for safety-related purposes than other drivers throughout the course of the day. However, during nighttime hours, specifically those directly before and after midnight, black females are also less likely to be stopped for safety-related purposes than other drivers. In turn, this means that black drivers are more likely to be subjected to investigative stops that are not for moving violations. The rate of safety-related stops is higher for all drivers during the daytime hours, during which the disparity between black males and other drivers is greatest. For much of the daytime, white females have the highest rate of safety-stops, while black females and white males have a similar percentage of stops classified as such. From 5AM to 6AM, black females have insufficient data and therefore are not displayed.
Figure 13. Hourly breakdown of percent of stops resulting in search, by race-gender category
Figure 13 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 across almost the entire day, but the time of day does significantly influence the rate at which they are searched. Search rates of black males are relatively lower for much of the daytime, and are significantly higher during the nighttime hours directly after midnight. All groups see increased search rates during these hours. However, white males only see slightly higher search rates than female drivers during this portion of the day, while black males are searched at a substantially higher rate. During the daytime hours, the search rate for white males is also quite comparable to female drivers. White and black females are searched at similar levels throughout the entire day, with the exception of 4AM. 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 14. Hourly breakdown of percent of stops resulting in arrest, by race-gender category
Figure 14 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. From midnight to 3AM, male drivers as well as white females are arrested at similar rates, while black females are arrested at a lower rate. The arrest rate for black males sharply increases to about 15% at 5AM, but is below 10% for all other hours of the day. During daytime hours, black males are the most likely to be arrested, but the arrest rate does not typically surpass 5%. For the daytime hours, white males and all females have comparable arrest rates. 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 15. Number of stops by officer
Figure 15 displays the distribution of number of stops by officer across the 2002-2020 time period. All officers displayed have over 100 traffic stops. 147 of 178 officers included in the data have less than 1000 traffic stops.
Figure 16. Percent black of drivers pulled over by officer
Figure 16 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, 20.7% of stops are of black drivers, while black people only make up 12.4% 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 30% of stops for a significant portion of officers. At the far right, the Figure shows that there are 33 officers whose mix of drivers stopped is more than 30% black.
Figure 17. Officer search rates by race
Figure 17 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, the median officer has a search rate of 6.45%, meaning that black male drivers are searched in 6.45% of traffic stops. A significant portion of officers have search rates that are much higher than this median value, meaning that searches occur more often for certain officers in traffic stops involving black males. For white male drivers, the median officer has a search rate of 1.84%. This indicates that the median officer in Huntersville is searching black males at a higher rate than they are searching white males.
Figure 18. Black-White Ratio of search rates by officer, for males
Figure 18 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 2.05, 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 some searching black male drivers at 3 or more times the rate of white male drivers, and a seven different officers searching black males are more than 10 times the rate.
Figure 19. Search rate versus hit rate by officer
Figure 19 presents the hit rates and search rates of individual officers who meet the criteria. As the Figure shows, 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 significant correlation between the two (but few officers in the analysis). In contrast to other cities, which show very low correlations between hit rates and search rates, officers in the Huntersville PD show a high correlation. Certain officers search drivers at extremely high rates and have high hit rates, whereas others search at a much lower rate and have low hit rates. 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. It is unclear why the Huntersville PD diverges from state-wide trends, though the fact that only 16 officers are included in the analysis should be kept in mind.